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Cesium dicyanamide Cs[C2N3] (≡ Cs[N(CN)2] or Cs[dca]) was obtained by a metathesis reaction in form of transparent colorless platelets. The results of single-crystal X-ray structure measurements and refinements (C2/c, Z = 8) with the monoclinic cell parameters a = 932.31(8), b = 1274.67(9), c = 824.94(7) pm, β = 110.803(3)° at −70 °C and a = 939.59(7), b = 1281.58(8), c = 827.57(6) pm, β = 110.610(3)° at 20 °C corroborate earlier results for this compound. The Raman and IR spectra of Cs[C2N3] are presented for the first time and the result compares well with those of NaCs2[C2N3]3. The heat-driven cyclotrimerization process of Cs[C2N3] was studied by thermal analyses (DSC) and temperature-dependent X-ray powder diffraction methods. At 370 °C, its trimerization product Cs3[C6N9] is formed, crystallizing in the orthorhombic space group Pbam with the cell parameters a = 3043.0(3), b = 1052.4(1) and c = 415.21(4) pm for Z = 4. The IR spectrum of this cesium tricyanomelaminate (Cs3[C6N9] or Cs3[TCM]) is presented, but a well-resolved Raman spectrum could not be acquired owing to fluorescence phenomena. An overview about the cyclotrimerization reactions of all pseudo-binary alkali-metal dicyanamides (A[C2N3]) to their corresponding tricyanomelaminates (A3[C6N9]) with A = Li–Cs gives a basis for a discussion of the different thermal and structural characteristics. [ABSTRACT FROM AUTHOR]

The synthesis and structural analysis of three new chloride-containing lithium thiophosphates(V) Li4Ln[PS4]2Cl with trivalent lanthanoids (Ln = Pr, Nd and Sm) are presented and discussed. Single crystals of Li4Sm[PS4]2Cl were obtained and used for crystal structure determination by applying X-ray diffraction. The other compounds were found to crystallize isotypically in the monoclinic space group C2/c. Thus, Li4Sm[PS4]2Cl (a = 2089.31(12) pm, b = 1579.69(9) pm, c = 1309.04(8) pm, β = 109.978(3)°, Z = 12) was used as a representative model to further describe the crystal structure in detail since Li4Pr[PS4]2Cl and Li4Nd[PS4]2Cl were confirmed to be isotypic using powder X-ray diffraction measurements (PXRD). In all cases, a trigonal structure in the space group R 3 ¯ (e.g., a = 1579.67(9) pm, c = 2818.36(16) pm, c/a = 1.784, Z = 18, for Li4Sm[PS4]2Cl) displaying almost identical building units worked initially misleadingly. The structure refinement of Li4Sm[PS4]2Cl revealed bicapped trigonal prisms of sulfur atoms coordinating the two crystallographically distinct (Sm1)3+ and (Sm2)3+ cations, which are further coordinated by four anionic [PS4]3− tetrahedra. The compounds also contain chloride anions residing within channel-like pores made of [PS4]3− units. Eight different sites for Li+ cations were identified with various coordination environments (C.N. = 4–6) with respect to chlorine and sulfur. EDXS measurements supported the stoichiometric formula of Li4Ln[PS4]2Cl, and diffuse reflectance spectroscopy revealed optical band gaps of 2.69 eV, 3.52 eV, and 3.49 eV for Li4Sm[PS4]2Cl, Li4Nd[PS4]2Cl, and Li4Pr[PS4]2Cl, respectively. The activation energy for Li+-cation mobility in Li4Sm[PS4]2Cl was calculated as Ea(Li+) = 0.88 eV using BVEL, which indicates potential as a Li+-cation conductor. [ABSTRACT FROM AUTHOR]

The conversion of La2O3 with HCl, subsequent neutralization and precipitation using (NH4)2CO3 in an industrial process leads to the previously unknown La2(CO3)3 ⋅ 5H2O. The phase was characterized by X‐ray powder diffraction leading to an averaged crystal structure model, thermal analysis, vibrational and optical spectroscopy. La2(CO3)3 ⋅ 5H2O crystallizes in space group Pbca(61) with a=9.0167(4) Å, b=12,842(3) Å, c=9.6331(4) Å and V=1115.4(3) Å3. The structure consists of ∞2LaCO34/4+ ${{}_{{\rm { \infty }}}{}^{{\rm { 2}}}\left\{{\left({\rm { La}}{\left({{\rm { CO}}}_{{\rm { 3}}}\right)}_{{\rm { 4/4}}}\right)}^{{\rm { +}}}\right\}}$ zig zag layers and a highly disordered interlayer space occupied by water molecules and carbonate anions. Partially occupied water‐related oxygen positions theoretically allow for a flexible hydrate water content La2(CO3)3 ⋅ xH2O, with x ranging from 1.5 to 5.0. Although a strong structural relationship between La2(CO3)3 ⋅ 5H2O and La2(CO3)3 ⋅ 8H2O and similar substance properties were found, the title compound cannot be obtained by partial dehydration of the octahydrate. Instead, both lanthanum carbonate hydrates transform into strongly disordered La2(CO3)3 in a one‐step dehydration process. [ABSTRACT FROM AUTHOR]

A new six‐membered cyclic alkanolamine with chemical formula C6H15N3O3 was synthesized by the reaction of glycolaldehyde with gaseous ammonia. The molecular structure, characterized by a hexagonal ring of alternating carbon and nitrogen atoms with three hydroxymethyl groups attached to the carbon atoms, could not be unambiguously determined by elemental analysis and 1H/13C/15N NMR. The molecular structure and conformation were further determined using a combination of vibrational spectroscopy (IR and Raman) and real‐space pair distribution function (PDF) analysis. The crystal structure was determined ab initio from laboratory X‐ray powder diffraction (XRPD) with orthorhombic space group Ama2 (No. 40) and unit‐cell parameters a = 12.1054 (2) Å, b = 13.5537 (2) Å and c = 5.20741 (8) Å. Consistent structure models could be obtained by symmetry‐independent PDF and PDF‐Rietveld co‐refinements. Independent local structure refinements indicate that the most likely deviations from the average structure consist of small tilting and translational distortions of hydrogen‐bonded molecular stacks. Thermal analysis (TG/DTA) and temperature‐dependent XRPD measurements were also performed to determine the thermal behavior. [ABSTRACT FROM AUTHOR]

Li[SCN]·THF and Li[SCN]·2THF can be obtained from solutions of anhydrous Li[SCN] in tetrahydrofuran (C4H8O, THF). Both compounds are very hygroscopic and slowly decompose even at room temperature. At ambient conditions Li[SCN]·THF crystallizes in the monoclinic space group P21/c with the lattice parameters a = 574.41(2), b = 1643.11(6), c = 830.15(3) pm and β = 99.009(1)° for Z = 4 as determined by laboratory X-ray powder diffraction. Its crystal structure contains Li+ cations surrounded by one THF molecule and three thiocyanate anions [SCN]− forming {Li[NCS]2[SCN](OC4H8)}2− tetrahedra, which join together as pairs via shared N⋯N edges. CHNS combustion analysis and vibrational spectroscopy confirmed its composition, whereas differential scanning calorimetry and thermogravimetric analysis coupled with a mass spectrometer were applied to record its thermal behaviour. Li[SCN]·2THF crystallises in a primitive monoclinic lattice as well, but in the space group P21/n with the lattice parameters a = 1132.73(3), b = 1637.98(3), c = 1264.88(2) pm and β = 94.393(2)° for Z = 8 as determined from single-crystal X-ray diffraction data at 100 K. Its structure contains two crystallographically independent Li+-centred tetrahedra {Li[NCS]2(OC4H8)2}−, which form dimers {(C4H8O)2Li[μ2-NCS]2Li(OC4H8)2} via shared N⋯N edges. They are merely stabilised by weak agostic H⋯S interactions between some CH2-groups of the C4H8O molecules and the [NCS]− ligands. [ABSTRACT FROM AUTHOR]

Mg(SCN)2·4H2O can be converted into previously unknown compounds Mg(SCN)2·(4 − x) H2O·xTHF with x = 0, 2 and 4 by multiple recrystallization in tetrahydrofuran (THF). The phases were characterized by infrared spectroscopy (IR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), and their crystal structures were solved from X-ray powder diffraction (XRPD) data. In the crystal structures isolated Mg(NCS)2(H2O)4−x(THF)x units form layered motifs. The thermal behavior of Mg(SCN)2·4H2O and Mg(SCN)2·4THF was investigated by temperature dependent in situ XRPD, where Mg(SCN)2·4THF was found to acquire a room temperature (α-form) and high temperature modification (β-form). The phase transformation is associated with an order–disorder transition of the THF molecules and with a reversion of the stacking order of the layered motifs. Further heating eventually leads to the formation of Mg(SCN)2·2THF. There thiocyanate related sulfur atoms fill the voids in the coordination sphere of magnesium, which leads to the formation of one dimensional electroneutral ∞[Mg(NCS)2/2(SCN)2/2(THF)2] chains. All investigated Mg(SCN)2·(4 − x) H2O·xTHF phases exhibit a remarkable anisotropic thermal expansion, and Mg(SCN)2·4H2O and Mg(SCN)2·2THF were found to show both positive and negative thermal expansion coefficients. [ABSTRACT FROM AUTHOR]

Cyclic peptoids are macrocyclic N‐substituted oligoglycines, with remarkable structural, chemical and physical properties. The gas adsorption properties of a permanently porous hexameric cyclopeptoid decorated with four propargyl and two methoxyethyl side chains were monitored by in situ X‐ray powder diffraction (XRPD). High‐resolution XRPD data together with Rietveld and density functional based tight binding (DFTB) method allowed us to locate propyne guest molecules inside the host channels, even though the powder sample contains more than one phase. We were able to characterize the host‐guest interactions, providing useful information on the host recognition sites and discuss host adaptiveness and host–guest chemical affinity in comparison with analogous compounds. [ABSTRACT FROM AUTHOR]

The solid state assembly of two cyclic hexapeptoids decorated respectively with five and six carbon N-alkyl side chains is analyzed by single crystal X-ray diffraction, intermolecular energies and lattice energy calculations. Thermal analysis and variable temperature X-ray powder diffraction were also carried out to analyze their thermal behaviour. The crystal structures of the two compounds feature architectural similarities, but also small relevant differences due to side chains-to-side chains interactions, which can explain the observed differences in the thermal properties. The compound with N-pentyl side chains exhibits a phase transition upon cooling down from room temperature to 100 K, while that with N-hexyl side chains features no phase transformation on cooling, instead a phase transformation occurs at 335 K upon heating. [ABSTRACT FROM AUTHOR]

Time-resolved mechanochemical cocrystallisation studies have so-far focused solely on neat and liquid-assisted grinding. Here, we report the investigation of polymer-assisted grinding reactions using in situ X-ray powder diffraction, revealing that reaction rate is almost double compared to neat grinding and independent of the molecular weight and amount of the polymer additive used. [ABSTRACT FROM AUTHOR]

Reaction of Mn(NCS)2 with 4‐picoline (4‐methylpyridine) leads to the formation of [Mn(NCS)2(4‐picoline)4]·0.67·4‐picoline·0.33·H2O (1‐Mn) reported in literature, Mn(NCS)2(4‐picoline)2(H2O)2 (2‐Mn/H2O), and of [Mn(NCS)2(4‐picoline)2]n (2‐Mn/I). 1‐Mn and 2‐Mn/H2O consist of discrete complexes, in which the metal cations are octahedrally coordinated, whereas in 2‐Mn/I the metal cations are linked by pairs of μ‐1,3‐bridging thiocyanate anions into corrugated chains. Measurements using thermogravimetry and differential scanning calorimetry as well as temperature dependent X‐ray powder diffraction on 1‐Mn and 2‐Mn/H2O reveal that upon heating both compounds transform into [Mn(NCS)2(4‐picoline)]n (3‐Mn) via 2‐Mn/I as intermediate. 3‐Mn shows a very rare chain topology in which the metal cations are linked by μ‐1,3,3 (N,S,S) coordinating anionic ligands which was never observed before with MnII. From these investigations there is no hint that a further modification of 2‐Mn can be prepared as recently observed for [M(NCS)2(4‐picoline)2]n (M = Fe, Cd) and such a form is also not available if the metastable forms of the FeII or CdII compounds were used as template during thermal decomposition. Magnetic investigations on 2‐Mn/H2O show only paramagnetic behavior, whereas for 2‐Mn/I antiferromagnetic ordering is observed. Finally, the crystal structure of Mn(NCS)2 was determined from XRPD data, which shows that it is strongly related to that of 3‐Mn. [ABSTRACT FROM AUTHOR]

Ferrous glycine sulfate pentahydrate [Fe(glycine)(SO4)·5H2O with glycine = C2H5NO2], contained in the supplement for treating iron deficiency anaemia, commercially known as ferro sanol duodenal®, was characterized by laboratory X‐ray powder diffraction (XRPD), scanning electron microscope (SEM), and infrared spectroscopy (IR). The thermal behavior was investigated by thermal analysis (TGA and DTA) and temperature‐dependent in situ XRPD measurements. Furthermore, the phase transitions to a less hydrated form [Fe(glycine)(SO4)·3H2O] and successively to the anhydrous form were demonstrated to occur in the crystalline solid state. Compared to the crystal structure of the pentahydrate, the trihydrate exhibits a different coordination environment of the iron sites where glycine ligands bridge iron forming a 1D polymeric chain structure. From detailed structural comparison, the mechanism of the phase transitions can be concluded. [ABSTRACT FROM AUTHOR]

During the systematic investigation of the ternary system Ca(CH3COO)2–Ca(HCOO)2–H2O at room temperature, the congruent crystallisation of two solid calcium acetate formates was observed: the hitherto unknown Ca3(CH3COO)4(HCOO)2·4H2O and the poorly characterised Ca(CH3COO)(HCOO)·H2O. The latter is a frequently observed efflorescence phase found on calcareous objects and it could be also identified as a corrosion phase in a natural history collection of birds' eggs. Elemental and thermal analyses were employed to determine the phase compositions and by Raman and IR spectroscopy the presence of acetate and formate anions in both solids was confirmed. Laboratory X-ray powder diffraction data were used to solve the crystal structures. Ca3(CH3COO)4(HCOO)2·4H2O crystallises in a primitive tetragonal unit cell with space group P41212 and lattice parameters of a = 6.8655(1) Å and c = 45.5454(6) Å, while Ca(CH3COO)(HCOO)·H2O crystallises in a primitive monoclinic unit cell with space group P21/c and lattice parameters of a = 9.2729(1) Å, b = 6.8002(1) Å, c = 11.2219(2) Å and β = 121.232(1)°. Calcium carboxylate zig-zag chains [Ca(μ2-RCOO)+]n (R = CH3 or H) are the main motif of both crystal structures. In Ca3(CH3COO)4(HCOO)2·4H2O these chains are exclusively composed of acetate anions, whereas in Ca(CH3COO)(HCOO)·H2O only formate anions are situated in the chains. The remaining places in the 7–8 fold coordination sphere of the calcium cations are filled by water molecules and additional carboxylate anions that interconnect neighbouring chains, which eventually leads to layered motifs in both structures. [ABSTRACT FROM AUTHOR]

Pure anhydrous Cu(CH3COO)2 was obtained both, by thermal dehydration of Cu(CH3COO)2·H2O and by drying a commercially purchased mixture of Cu(CH3COO)2·H2O and Cu(CH3COO)2 in a nitrogen atmosphere using P2O5 as drying agent. The crystal structure was solved ab initio from synchrotron X‐ray powder diffraction (XRPD) data at 150 °C and from laboratory XRPD data at ambient conditions and found to be isotypic to anhydrous chromium(II), molybdenum(II) and rhodium(II) acetate. Cu(CH3COO)2 crystallizes in space group P1 (no. 2) with lattice parameters of a = 5.1486(3) Å, b = 7.5856(6) Å, c = 8.2832(6) Å, α = 77.984(4)°, β = 75.911(8)°, γ = 84.256(6)° at ambient conditions. Cu2(CH3COO)4 paddle wheels with short (2.6 Å) Cu–Cu distances form chains in a direction, which is the main motif in the crystal structure. Due to their identical structural main motif Cu(CH3COO)2·H2O and Cu(CH3COO)2 exhibit a similar bluish‐green color, almost identical UV/Vis spectra and comparable magnetic properties. The temperature dependent magnetic susceptibility also indicates only weak inter‐dimer spin exchange between neighbouring Cu2(CH3COO)4 paddle wheels. [ABSTRACT FROM AUTHOR]

Powder samples of Ag3LiIr2O6 and Ag3LiRu2O6 were synthesized from α-Li2IrO3 and Li2RuO3 respectively by ion exchange in an AgNO3 melt. The crystal structures of the title compounds were solved from high resolution laboratory X-ray powder diffraction (XRPD) patterns and from pair distribution function (PDF) analysis using synchrotron X-ray powder diffraction data. In both crystal structures edge sharing LiO6/3- and (Ir/Ru)O6/3-octahedra form honeycomb like layers that are stacked in a staggered fashion. Silver cations, situated in-between the layers mediate the interlayer interactions by linear O–Ag–O bonds. Anisotropic peak broadening in the XRPD patterns and diffuse scattering occurring as streaks in the precession electron diffraction (PED) patterns indicate the presence of stacking faults, which could be also visualized by high resolution transmission electron microscopy (HRTEM). Possible alternative stacking sequences were derived from the ideal crystal and incorporated into a microstructure model. By applying a supercell approach that randomly generates and averages stacking sequences based on transition probabilities and combining it with a grid search algorithm, the microstructures, i.e. the degrees of faulting in the structures of the title compounds were refined to the measured XRPD data. In result the crystal structures of Ag3LiIr2O6 and Ag3LiRu2O6 were found to be vastly faulted with almost no coherence of the stacked layers. [ABSTRACT FROM AUTHOR]

Reaction of Cd(NCS)2 or Zn(NCS)2 with 3-aminomethylpyridine (3-AMPY) leads to the formation of five compounds with the compositions [Cd(NCS)2(3-AMPy)2·(3-AMPy)]n (1-Cd), [M(NCS)2(3- AMPy)2]n [M = Cd (2-Cd), Zn (2-Zn)] [Cd(NCS)2(3-AMPy)]n (3-Cd), and [Zn(NCS)2(3-AMPy)]2 (3-Zn). In 1-Cd the Cd cations are linked by the 3-AMPy ligands into layers that consist of rings, built up of four Cd cations and four 3-AMPy ligands. These layers are stacked to form channels, in which the 3-AMPy solvate molecules are located. In the isotypic compounds 2-Cd and 2-Zn the metal cations are also linked into layers by the 3-AMPy ligands with an identical layer topology as that in 1-Cd, but a completely different conformation of the 3-AMPy ligand. In the most 3-AMPy deficient compound 3-Cd, the Cd cations are linked by μ- 1,3-bridging thiocyanate anions and 3-AMPy ligands into chains, that are further connected into layers by additional anionic ligands. In 3-Zn two Zn cations are linked by pairs of 3-AMPy ligands into discrete dimers. Thermoanalysis and X-ray powder diffraction (XRPD) investigations show that upon heating 1-Cd transforms into 2-Cd and 2-Zn into 3-Zn. The compounds 2-Cd, 3-Cd, 2-Zn and 3-Zn present ligand-based luminescence in the blue-green spectral range with maxima between 21276 and 21795 cm-1. [ABSTRACT FROM AUTHOR]

Two hitherto hardly characterized glycine zinc sulfates were identified in the product of a batch production process for glycine zinc sulfates of the BASF Company: Gly·ZnSO4·2H2O and β-Gly-ZnSO4. The crystal structures were solved from high resolution synchrotron X-ray powder diffraction data. Gly·ZnSO4·2H2O is the zinc analogue to an isotypic copper compound with space group P21/c (no. 14) and a = 7.8092(1) Å, b = 12.3979(2) Å, c = 8.3732(1) Å, β = 90.673(1) and V = 810.62(2) Å3. The crystal structure of the hitherto unknown β-Gly-ZnSO4 with space group P21/c (no. 14) and a = 9.2577(1) Å, b = 5.1268(1) Å, c = 12.9926(1) Å, β = 90.267(1) and V = 616.65(1) Å3 was solved ab initio. In both crystal structures the zinc cations exhibit exotic, fivefold coordination arrangements: squared ZnO5-pyramids are present in the structure of the dihydrate, whereas the crystal structure of β-Gly-ZnSO4 contains trigonal ZnO5- bipyramids. [ABSTRACT FROM AUTHOR]

The reaction of Ni[CO 3 ] with an aqueous solution of the free acid (H 3 O) 2 [B 12 Cl 12 ] leads to green single crystals with the composition Ni(H 2 O) 6 [B 12 Cl 12 ] · 6 H 2 O. This compound crystallizes in the orthorhombic space group Pnnm with a = 1798.86(9), b = 1312.49(7), c = 1373.63(7) pm for Z = 4. Thermal decomposition studies revealed the possibility for a multi-step dehydration process with the loss of all interstitial and cation-hydrating crystal water molecules. Temperature-dependent X-ray powder diffraction (XRPD) measurements show two characterizable degradation products between 30 and 450 °C. Ni(H 2 O) 6 [B 12 Cl 12 ] was obtained at 30 °C after the loss of all interstitial water molecules as pale green powder with a cubic crystal structure ( a = 1700.02(5) pm, Z = 8) and Fm 3 ¯ c as space group, displaying a CsCl-type arrangement. The six water molecules of hydration, which coordinate each Ni 2+ cation show fourfold disorder. Above 450 °C all remaining water molecules have left the sample and the color shifts to yellow indicating the formation of anhydrous Ni[B 12 Cl 12 ]. This water-free salt crystallizes also in the cubic system ( a = 986.71(9) pm, Z = 2), but with Im 3 ¯ as space group. In the crystal structure the Ni 2+ positions are occupied only by 1 / 4 and each of them is coordinated by two [B 12 Cl 12 ] 2− anions attached via two faces offering six chlorine atoms in an octahedral shape. [ABSTRACT FROM AUTHOR]

The solid/liquid equilibria in the ternary system Ni(OH)2-NiCl2-H2O at temperatures of 25 and 200 °C have been investigated by applying equilibration periods of up to 45 months (3 years and 9 months). The equilibration process was studied by isothermal saturation methods using different solids as starting materials. At 200 °C, Ni2Cl(OH)3 and NiCl(OH) occur as stable phases, whereas a solid solution, NiClx(OH)2-x (ss-type-OH), appears as an intermediate phase. At 25 °C, two nickel(II) chloride hydroxide hydrates, Ni3Cl2+x(OH)4-x·4H2O and Ni3Cl(OH)5·4H2O, are formed. The latter phase was characterized for the first time and a structural model was created from a Rietveld refinement of the powder X-ray diffraction pattern. A systematic investigation of the solubilities at 25 °C revealed that Ni2Cl(OH)3 is the solid phase in both dilute and concentrated NiCl2 solutions at this temperature. In general, all stable and metastable phases in the system Ni(OH)2-NiCl2-H2O exhibit very low solubility, but during the very slow phase transformations high hydroxide supersaturations occur that are persistent for years. [ABSTRACT FROM AUTHOR]

A sample of pure, artificial hellyerite was synthesized in aqueous solution at 0 °C. The recorded X-ray diffraction pattern completely agrees with the reference data given for natural hellyerite. Laboratory high resolution X-ray powder diffraction, applying global optimization methods and Rietveld refinement, was employed to solve the crystal structure. Synthetic hellyerite was determined to crystallize in the primitive monoclinic space group P2/ m (no. 10) with a = 10.769(2) Å, b = 7.295(2) Å, c = 9.343(2) Å, and β = 94.042(2)°. The crystal structure consists of edge-linked, isolated pairs of Ni2(CO3)2(H2O)8 octahedra and non-coordinating water molecules. According to structure solution and thermal analysis the molecular formula of hellyerite was corrected from NiCO3 ·6H2O to NiCO3 ·5.5H2O. The title compound was characterized by scanning electron microscopy, IR-, Raman-, and UV/Vis spectroscopy. [ABSTRACT FROM AUTHOR]

The previously unknown nickel chloride hydroxide phases Ni3Cl2+ x(OH)4- x ·2H2O ( x = 0.26, 0.48, 0.82) have been synthesized in concentrated aqueous NiCl2 solutions and investigated in detail. Crystal structure determination from X-ray powder diffraction data revealed triple chains of distorted, edge-linked NiO6 and NiO3(O/Cl)3 octahedra as the main building blocks. The chains exhibit a layer-like configuration and therefore great structural similarity to nickel-layered hydroxy halides (Cl, Br, I) and β-Ni(OH)2. Increasing chloride content in Ni3Cl2+ x(OH)4- x ·2H2O leads to a reduction of the space group symmetry from C2/ m (12) for x = 0.26 and 0.48 to P $\bar {1}$ (2) for x = 0.82 and to distinct shifts in their thermal, spectral, and magnetic properties. Each solid exhibits a maximum magnetic susceptibility in the range 5.9-9.7 K, which indicates antiferromagnetic ordering. Positive Curie-Weiss temperatures, θ, were found, which points to predominantly ferromagnetic spin-exchange interactions. In addition, broad maxima of the magnetic susceptibility evidence a low-dimensional magnetic character as the most prominent feature of the magnetic properties of the investigated phases. [ABSTRACT FROM AUTHOR]

The crystal structure of ferrous glycine sulfate (a ferroglycine sulfate complex with chemical formula FeSO4(C2H5NO2), a compound extensively used as an iron dietary supplement, was refined from synchrotron X-ray powder diffraction data. The crystal structure of an (so-far unreported) isostructural manganese analogue was also structurally detailed by a Rietveld refinement against the corresponding X-ray powder diffraction pattern. All studied compounds crystallize in the monoclinic P21 space group, building layers of metal cations coordinated by the oxygen atoms of sulfate groups and glycine ligands. Neighboring layers are parallel packed, bonded by hydrogen bonds. The coordination polyhedra around the cations can be regarded as distorted and elongated octahedral, presumably due to severe strains present in the crystal structure of the layers. [ABSTRACT FROM AUTHOR]

A new basic nickel carbonate Ni12(CO3)8(OH)8·(x – 1)H2O or Ni12(CO3)8(OH)6O·xH2O (x = 6–8) was synthesized by two hydrothermal methods. The crystal structure was determined in the cubic space group P43m (215) with a = 8.3814(2) Å by laboratory high-resolution X-ray powder diffraction with the application of global optimization methods and Rietveld refinement. The crystal structure consists of edge-linked [NiO6] octahedra and carbonate units that form cages. The interconnected cages form channels filled with disordered water molecules. This causes a zeolite-like behavior of the water molecules, as shown by thermogravimetric analysis coupled with infrared spectroscopy (TG–IR) and in situ X-ray powder diffraction experiments up to 300 °C. In addition, the title compound was characterized by elemental analysis, scanning electron microscopy, and Raman and UV/Vis spectroscopy. The title compound was proven to be a pure carbonate and not nickel hydrogen carbonate (PDF 15-0782), as was assumed before. [ABSTRACT FROM AUTHOR]

Two samples of pure NiCl(OH) were produced by hydrothermal synthesis and characterized by chemical analysis, IR spectroscopy, high-resolution laboratory X-ray powder diffraction and scanning electron microscopy. Layers composed of edge-sharing distorted NiCl6 x(OH)6−6 x octahedra were identified as the main building blocks of the crystal structure. NiCl(OH) is isostructural to CoOOH and crystallizes in space group R m [ a = 3.2606 (1), c = 17.0062 (9) Å]. Each sample exhibits faults in the stacking pattern of the layers. Crystal intergrowth of ( Aγ B)( Bα C)( Cβ A) and ( Aγ B)( Aγ B) [C6 like, β-Ni(OH)2 related] stacked layers was identified as the main feature of the microstructure of NiCl(OH) by DIFFaX simulations. A recursion routine for creating distinct stacking patterns of rigid-body-like layers in real space with distinct faults (global optimization) and a Rietveld-compatible approach (local optimization) was realized and implemented in a macro for the program TOPAS for the first time. This routine enables a recursive creation of supercells containing ( Aγ B)( Bα C)( Cβ A), ( Aγ B)( Aγ B) and ( Cβ A)( Bα C)( Aγ B) stacking patterns, according to user-defined transition probabilities. Hence it is an enhancement of the few previously published Rietveld-compatible approaches. This routine was applied successfully to create and adapt a detailed microstructure model to the measured data of two stacking-faulted NiCl(OH) samples. The obtained microstructure models were supported by high-resolution scanning electron microscopy images. [ABSTRACT FROM AUTHOR]

A novel approach for the marking of deposited lithium on graphite anodes from large automotive lithium-ion cells (≥6 Ah) is presented. Graphite anode samples were extracted from two different formats (cylindrical and pouch cells) of pristine and differently aged lithium-ion cells. The samples present a variety of anodes with various states of lithium deposition (also known as plating). A chemical modification was performed to metallic lithium deposited on the anode surface due to previous plating with isopropanol (IPA). After this procedure an oxygenated species was detected by scanning electron microscopy (SEM), which later was confirmed as Li2CO3 by Fourier transform infrared spectroscopy (FTIR) and X-ray powder diffraction (XRPD). A valuation of the covered area by Li2CO3 was carried out with an image analysis using energy-dispersive X-ray spectroscopy (EDX) and quantitative Rietveld refinement. [ABSTRACT FROM AUTHOR]

In the course of the investigation of glass-induced metal corrosion processes, a microcrystalline sodium copper formate hydroxide oxide hydrate, Cu4Na4O(HCOO)8(H2O)4(OH)2, was detected on a series of antique works of art, and its crystal structure was determined ab initio from high-resolution laboratory X-ray powder diffraction data using the method of charge flipping, simulated annealing, and difference-Fourier analysis (P42/n, a = 8.425 109(97) Å, c = 17.479 62(29) Å, V = 1240.747(35) ų, Z = 8). In the crystal structure, the metal cations are interconnected in a two-dimensional metal-organic framework via the oxygen atoms of the formate, hydroxide, and oxide anions. Doublets of face-sharing square pyramidal Cu2+ polyhedra are linked via a single, central oxide oxygen atom to give a paddle-wheel arrangement, while the Na+ cations are organized in Na2O11 moieties with highly disordered, edge-sharing octahedral coordination. In addition, hydrogen bonding plays an important role in stabilizing the crystal structure. [ABSTRACT FROM AUTHOR]

Almost a century has passed since the pioneering work of Debye, Scherrer, and Hull and their first powder X-ray diffraction experiments in 1916/17. Although these pioneers and many others discovered most of the fundamental concepts in the field of powder diffraction within the first few years, nobody at that time could foresee the development of the computer and its calculating power in the 21st century. The general availability of computing power changed the field of powder diffraction, as Hugo Rietveld showed with his computer-assisted whole powder pattern fitting concept around fifty years after the first powder diffraction patterns were observed. Nowadays, much more complex algorithms are used to solve and identify crystal structures from powders. The intention of this historical review is to show some of the most important developments from the viewpoint of the authors in the field of powder diffraction in the last century, from the beginnings of the first transmission experiments and the determination of simple cubic crystal structures to the techniques of today allowing for the refinement of thousands of atoms within one unit cell. [ABSTRACT FROM AUTHOR]

The crystal structure of magnesium potassium arsenate hexahydrate, MgKAsO4 ·6H2O, was refined from powder diffraction data. MgKAsO4 ·6H2O crystallizes in the orthorhombic space group Pmn21 with Z = 2, as the biomineral struvite. Complete dehydration of MgKAsO4 ·6H2O proceeds in a single step, with one endothermic peak at 87.9 °C ( Tonset). The infrared and Raman spectra of protiated and deuterated polycrystalline samples were recorded at room temperature and at the boiling temperature of liquid nitrogen (LNT). The assignments of the observed bands are proposed and spectra-structure correlations are made. [ABSTRACT FROM AUTHOR]

Phase-pure ScF[SeO3] and YF[SeO3] were synthesized via solid-state reactions of the corresponding rare-earth metal sesquioxides and trifluorides with selenium dioxide in excess of fluxing cesium bromide at 700 °C for 7 d. To avoid the formation of oxosilicates, these reactions took place in corundum crucibles embedded inside of evacuated fused silica ampoules. Upon cooling down below 13 °C, a pseudo-second-order phase transition ( P21/ m → P $\bar{1}$ or P1) for ScF[SeO3] occurs, which is similar to the high-temperature phase transition of LuF[SeO3]. By heating YF[SeO3] above 319 °C, it undergoes a first-order phase transition ( P21/ c → P21/ m) without passing the intermediate P $\bar{1}$ modification in contrast to LuF[SeO3]. Both the high-temperature phase transition of YF[SeO3] and the low-temperature phase transition of ScF[SeO3] were characterized by in-situ X-ray powder diffraction, X-ray single-crystal diffraction, thermal analysis DSC, and distortion-mode analysis. For both cases the driving forces for the symmetry-breaking phase transitions from the high- to the low-temperature phases are discussed. [ABSTRACT FROM AUTHOR]

Phase transitions recorded using in-situ powder diffraction are typically analysed by Rietveld refinements applying relative atomic coordinates in a least-squares iteration process. Although this choice of relative atomic coordinates gives an intuitive coordinate system, it can be improved by changing to another basis of the atomic configuration space, as the motion of whole atomic groups or polyhedra can be normally described with a smaller set of parameters. Using rotational rigid body symmetry modes as another basis, it is possible to directly describe and refine the rotation of groups of atoms (denoted as constrainable atomic groups). In addition, a reduction of the total number of relevant parameters can occur. In order to explore the capabilities of this new approach, phase transitions in different compounds, namely sodium niobate (NaNbO3), ferrocene (Fe(C5H5)2), and schafarzikite (FeSb2O4) are reinvestigated. [ABSTRACT FROM AUTHOR]

For the first time a basic transition-metal hydrate, Ni3Cl2.1(OH)3.9•4H2O, is found to be isostructural to a main-group metal phase, Mg3Cl2.0(OH)4.0-4H2O. The Ni phase was found as crystalline solid in the course of investigations into the formation of basic nickel(II) chloride phases at 25 and 40 °C in alkaline, concentrated nickel(II) chloride solutions. Ni3Cl2.1(OH)39•4H2O was characterized by thermal analysis, IR spectroscopy, scanning electron microscopy, and X-ray powder diffraction. The crystal structure was determined from high-resolution laboratory X-ray powder diffraction data. Ni3Cl2.1(OH)3.9•4H2O crystallizes in space group C2/m (12) with Z = 1, a = 14.9575(4) Å, b = 3.14131l) Å, c = 10.4818(5) Å,ß = 101.482(1)°, and V = 482.S0(3) ų. The main building unit of the structure is an infinite triple chain of edge-linked distorted NiO6 octahedra. These chains are separated by interstitial one-dimensional zigzag chains of disordered Cl- ions and H2O molecules. The crystal structures of Ni3Cl2.1(OH)3.9-4H2O and the isostructural magnesium salt hydrate Mg3Cl2(OH)4. 4H2O (2--1--4 phase) are compared in detail. [ABSTRACT FROM AUTHOR]

In a systematic approach, the ability of the Maximum Entropy Method (MEM) to reconstruct the most probable electron density of highly disordered crystal structures from X-ray powder diffraction data was evaluated. As a case study, the ambient temperature crystal structures of disordered α-Rb2[C2O4] and α-Rb2[CO3] and ordered δ-K2[C2O4] were investigated in detail with the aim of revealing the `true' nature of the apparent disorder. Different combinations of F (based on phased structure factors) and G constraints (based on structure-factor amplitudes) from different sources were applied in MEM calculations. In particular, a new combination of the MEM with the recently developed charge-flipping algorithm with histogram matching for powder diffraction data (pCF) was successfully introduced to avoid the inevitable bias of the phases of the structure-factor amplitudes by the Rietveld model. Completely ab initio electron-density distributions have been obtained with the MEM applied to a combination of structure-factor amplitudes from Le Bail fits with phases derived from pCF. All features of the crystal structures, in particular the disorder of the oxalate and carbonate anions, and the displacements of the cations, are clearly obtained. This approach bears the potential of a fast method of electron-density determination, even for highly disordered materials. All the MEM maps obtained in this work were compared with the MEM map derived from the best Rietveld refined model. In general, the phased observed structure factors obtained from Rietveld refinement (applying F and G constraints) were found to give the closest description of the experimental data and thus lead to the most accurate image of the actual disorder. [ABSTRACT FROM AUTHOR]

The compound tetrakis(trimethylsilyl)silane Si[Si(CH 3 ) 3 ] 4 (TSi) has been studied at room temperature for pressures up to 21.5(1) GPa, using X-ray powder diffraction with synchrotron radiation. Three different phases are reported in the investigated pressure range. The c.c.p.-type structure is stable up to a pressure of 0.19(1) GPa ( $ \hbox{Fm}\bar{3}\hbox{m} $ , a = 13.5211(1) Å, V = 2471.95(1) Å 3 , Z = 4 at 0.02(1) GPa). It shows a severe orientational disorder of the molecules. At pressures 0.19(1)-0.71(1) GPa a monoclinic phase (HP1) is found with space group P 2 1 / n and Z = 8 ( a = 17.746(1) Å, b = 16.098(1) Å, c = 16.871(1) Å, γ = 111.437(5) and V = 4486.3(8) Å 3 at 0.24(1) GPa). Another monoclinic phase (HP2) exists at pressures 0.52(1)-8.67(5) GPa. This phase has a smaller unit cell than the HP1 phase with Z = 2 ( a = 8.3778(8) Å, b = 9.1050(7) Å, c = 13.3024(8) Å, γ = 111.63(1) and V = 943.22(6) Å 3 at 1.73(2) GPa). The pressure dependencies of the unit-cell volumes are successfully described by Murnaghan or Vinet-type equations of state. The structures at different pressures and temperatures of TSi and related compounds are described as distorted superstructures of the c.c.p. arrangement. The occurrence of different superstructures is rationalized as the result of an optimized packing of ordered molecules of various shapes. [ABSTRACT FROM AUTHOR]

Reaction of Mn(NCS)2 with 4‐picoline (4‐methylpyridine) leads to the formation of [Mn(NCS)2(4‐picoline)4]·0.67·4‐picoline·0.33·H2O (1‐Mn) reported in literature, Mn(NCS)2(4‐picoline)2(H2O)2 (2‐Mn/H2O), and of [Mn(NCS)2(4‐picoline)2]n (2‐Mn/I). 1‐Mn and 2‐Mn/H2O consist of discrete complexes, in which the metal cations are octahedrally coordinated, whereas in 2‐Mn/I the metal cations are linked by pairs of μ‐1,3‐bridging thiocyanate anions into corrugated chains. Measurements using thermogravimetry and differential scanning calorimetry as well as temperature dependent X‐ray powder diffraction on 1‐Mn and 2‐Mn/H2O reveal that upon heating both compounds transform into [Mn(NCS)2(4‐picoline)]n (3‐Mn) via 2‐Mn/I as intermediate. 3‐Mn shows a very rare chain topology in which the metal cations are linked by μ‐1,3,3 (N,S,S) coordinating anionic ligands which was never observed before with MnII. From these investigations there is no hint that a further modification of 2‐Mn can be prepared as recently observed for [M(NCS)2(4‐picoline)2]n (M = Fe, Cd) and such a form is also not available if the metastable forms of the FeII or CdII compounds were used as template during thermal decomposition. Magnetic investigations on 2‐Mn/H2O show only paramagnetic behavior, whereas for 2‐Mn/I antiferromagnetic ordering is observed. Finally, the crystal structure of Mn(NCS)2 was determined from XRPD data, which shows that it is strongly related to that of 3‐Mn. [ABSTRACT FROM AUTHOR]

The crystal structure of 5[Zn(OH)2]·2[ZnSO4] is determined by powder XRD. [ABSTRACT FROM AUTHOR]

Review: 155 refs. [ABSTRACT FROM AUTHOR]

Powder samples of Ag3LiIr2O6 and Ag3LiRu2O6 were synthesized from α-Li2IrO3 and Li2RuO3 respectively by ion exchange in an AgNO3 melt. The crystal structures of the title compounds were solved from high resolution laboratory X-ray powder diffraction (XRPD) patterns and from pair distribution function (PDF) analysis using synchrotron X-ray powder diffraction data. In both crystal structures edge sharing LiO6/3- and (Ir/Ru)O6/3-octahedra form honeycomb like layers that are stacked in a staggered fashion. Silver cations, situated in-between the layers mediate the interlayer interactions by linear O–Ag–O bonds. Anisotropic peak broadening in the XRPD patterns and diffuse scattering occurring as streaks in the precession electron diffraction (PED) patterns indicate the presence of stacking faults, which could be also visualized by high resolution transmission electron microscopy (HRTEM). Possible alternative stacking sequences were derived from the ideal crystal and incorporated into a microstructure model. By applying a supercell approach that randomly generates and averages stacking sequences based on transition probabilities and combining it with a grid search algorithm, the microstructures, i.e. the degrees of faulting in the structures of the title compounds were refined to the measured XRPD data. In result the crystal structures of Ag3LiIr2O6 and Ag3LiRu2O6 were found to be vastly faulted with almost no coherence of the stacked layers. [ABSTRACT FROM AUTHOR]

White efflorescence crystals grown on the surfaces of a bronze bowl, classical ceramic and ancient wine jugs were investigated. X-ray powder diffraction (XRPD) revealed that in each case an identical, hitherto unknown phase was formed. The crystal structure was solved from high resolution XRPD measurements and revealed a phase composition of Ca 2 (CH 3 COO)(HCOO)(NO 3 ) 2 ·4H 2 O, which is in accordance with the complementary analysis. The overall structural motif of Ca 2 (CH 3 COO)(HCOO)(NO 3 ) 2 ·4H 2 O, one dimensional calcium carboxylate zig zag chains in which acetate and formate ions are arranged in an alternating fashion, is closely related to other naturally occurring or artificial efflorescence salts like thecotrichite or calclacite. [ABSTRACT FROM AUTHOR]

Crystal structures of substituted apatites with general formula Ca 10− x M x (PO 4 ) 6 (OH 1− δ ) 2−x O x , where M=La, Bi, 0≤ x <2, were refined using high-resolution X-ray powder diffraction patterns. Individual positions for Ca 2+ and M 3+ -ions localized near Ca2-site were determined. The M 3+ -ion was found shifted toward the hexagonal channel center with respect to the Ca 2+ -ion, forming very short bond with the intrachannel O 2− , while leaving considerably longer distances to other oxygen atoms, which suggested the existence of a MO + ion. Distinct bands of stretching M–O modes were observed in the Raman and FT-IR spectra of the compounds. The bond lengths for BiO + and LaO + were estimated to be 2.05(1) and 2.09(1) Å correspondingly. The latter was almost 0.3 Å lower than the shortest La–O bond in La 2 O 3 . The realization of such a strong lanthanide–oxygen bond in a crystal lattice could provide a very high axial ligand field and might be implemented to develop high-energy-barrier single-molecule magnets as well as to tune properties of lanthanide-based luminophores. [ABSTRACT FROM AUTHOR]

Two new ferrocene derivatives with amide linkages were synthesized by the condensation of 4-ferrocenylaniline with n-alkyl acid chloride derivatives as pristine orange solids in good yields. FTIR and 1 H/ 13 C NMR studies have confirmed the basic structure of the molecules with the involvement of intermolecular H-bonding, which together with the ferrocene-like packing ensures the stability of the crystal structure. Crystal structures for both compounds were solved by Rietveld refinements of high resolution X-ray powder diffraction data. The XRD results show that both compounds crystallize in the monoclinic space group P 2 1 / c . The primary feature of the crystal structure is a double layer of ferrocenyl groups stretched out in the b - c -plane perpendicular to the a -axis, with packing of the ferrocenyl groups occurring in a manner similar to that of pure ferrocene. Despite the close structural similarity, both compounds differ in the optimized geometry of respective Ferrocene conformers. The Cp rings are eclipsed for one Ferrocene conformer and close to staggered for the other, owing to the low energy barrier for the rotation of a cyclopentadienyl ring relative to the rest of the molecule. [ABSTRACT FROM AUTHOR]

Two merocyanine dyes containing a malononitrile or a ketone functional group as electronacceptors, and a piperidine group as electron-donor were synthetized and crystallized as pigments. The electron-donor and -acceptor moieties are linked via an octahydroanthracene skeleton, forming an electronic push-pull molecular system. The crystal structure of the malononitrile compound was solved ab initio from X-ray powder diffraction data, complementing the reported structure of the ketone pigment. Both compounds show similar molecular conformations in the solid state, yet with completely different crystal packing schemes. The crystal structures were analyzed by inspecting the Hirshfeld surfaces. IR spectroscopy was applied to complement the crystallographic study. The absorption characteristics of both pigments emerge from the push-pull chemical structure, which was visualized by plotting the electrostatic potentials, calculated using molecular geometries as observed in the solid state. The solid-state UV-vis spectra showed peak broadening and bathochromic spectral shift as compared to the spectra recorded in solution, depending on the polarity of the solvent molecules: The largest shifts of the spectra of solid-state pigments were observed with respect to the spectra recorded in toluene solution, whether the smallest to those in ethanol. [ABSTRACT FROM AUTHOR]

Reaction of cobalt thiocyanate with 4-acetylpyridine leads to the formation of [Co(NCS)2(4-acetylpyridine)2]n (3/I). In its crystal structure the Co cations are connected by pairs of μ-1,3-bridging thiocyanato ligands into dimers that are further connected into layers by single anionic ligands. DTA-TG measurements of Co(NCS)2(4-acetyl-pyridine)4 (1) led to the formation of 3/I. In contrast, when the hydrate Co(NCS)2(4-acetyl-pyridine)2(H2O)2 (2) is decomposed, a mixture of 3/I and a thermodynamically metastable form 3/II is obtained. Further investigations reveal that thermal annealing of 2 leads to the formation of 3/II, that contains only traces of the stable form 3/I. DSC and temperature dependent X-ray powder diffraction (XRPD) measurements prove that 3/II transforms into 3/I on heating. The crystal structure of 3/II was determined ab initio from XRPD data. In its crystal structure the Co cations are linked by pairs of bridging thiocyanato anions into a 1D coordination polymer, and thus, 3/II is an isomer of 3/I. Magnetic measurements disclose that the stable form 3/I only shows paramagnetism without any magnetic anomaly down to 2 K. In contrast, the metastable form 3/II shows ferromagnetic behavior. The phase transition into ordered state at Tc = 3.8 K was confirmed by specific heat measurements. Alternating current susceptibility measurements show frequency dependent maxima in χ' and χ", which is indicative for a slow relaxation of the magnetization. [ABSTRACT FROM AUTHOR]

Phase-pure ScF[SeO3] and YF[SeO3] were synthesized via solid-state reactions of the corresponding rare-earth metal sesquioxides and trifluorides with selenium dioxide in excess of fluxing cesium bromide at 700 °C for 7 d. To avoid the formation of oxosilicates, these reactions took place in corundum crucibles embedded inside of evacuated fused silica ampoules. Upon cooling down below 13 °C, a pseudo-second-order phase transition ( P21/ m → P $\bar{1}$ or P1) for ScF[SeO3] occurs, which is similar to the high-temperature phase transition of LuF[SeO3]. By heating YF[SeO3] above 319 °C, it undergoes a first-order phase transition ( P21/ c → P21/ m) without passing the intermediate P $\bar{1}$ modification in contrast to LuF[SeO3]. Both the high-temperature phase transition of YF[SeO3] and the low-temperature phase transition of ScF[SeO3] were characterized by in-situ X-ray powder diffraction, X-ray single-crystal diffraction, thermal analysis DSC, and distortion-mode analysis. For both cases the driving forces for the symmetry-breaking phase transitions from the high- to the low-temperature phases are discussed. [ABSTRACT FROM AUTHOR]

Hydration of anhydrous LiSCN by stoichiometric amounts of water vapor leads to the formation of LiSCN ⋅ 1 H 2 O. At room temperature, LiSCN ⋅ 1 H 2 O crystallizes in the monoclinic space group C 2/ m with a = 15.0271(3) Å, b = 7.5974(1) Å, c = 6.7070(1) Å, β = 96.147(6) ° and V = 761.32(2) ų (α-phase). At 49 °C, the material transforms into a high temperature β-phase with the orthorhombic space group Pnam and a = 13.2258(2) Å, b = 7.0619(9) Å, c = 8.1663(1) Å and V = 762.72(2) ų. Structural and thermodynamic investigations were conducted using infrared (IR) spectroscopy, ex situ and in situ X-ray powder diffraction (XRPD) while varying temperature or water partial pressure p H 2 O , differential scanning calorimetry (DSC) and direct measurements of equilibrium p H 2 O. The results indicate that LiSCN ⋅ 1 H 2 O is a special case when compared to LiSCN ⋅ n H 2 O (n = 0 or 2), both regarding crystal structure and hydration thermodynamics. These results are combined with literature date into an updated phase diagram of the LiSCN – H 2 O system, showing a detailed picture of the phase formation behavior of the LiSCN ⋅ n H 2 O hydrates. • Structure of LiSCN ⋅ 1H 2 O. • Hydration Thermodynamics. • LiSCN – H 2 O Phase Diagram. [ABSTRACT FROM AUTHOR]