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[Display omitted] • Two new acentric borates, Na 17 B 24 O 42 I 5 and Na 3 B 4 O 7 I, were characterized. • In the presence of NaI, Na 17 B 24 O 42 I 5 transforms into Na 3 B 4 O 7 I. • Their crystal structure is formed by a framework of B 4 O 9 tetraborate groups. Extensive searches for new monovalent metal borates as promising nonlinear optical materials continuously provide new exciting results. Attempts to add the iodine end-member of the acentric Na 3 B 4 O 7 X family resulted in a compound with a complex twofold monoclinic superstructure, Na 17 B 24 O 42 I 5. As for the lighter-halide analogies, its crystal structure is formed by a 12B:∞3[3(4:2Δ + 2T)] framework of B 4 O 9 tetraborate groups, 4B:2Δ2□:<Δ2□>=<Δ2□>, yet the guest metal-halide sublattice is less dense and contains 5 NaI per 6 Na 2 B 4 O 7 formula units, most likely due to the large size of the iodide ion. Upon heating in the presence of excess NaI, Na 17 B 24 O 42 I 5 converts into a simple hexagonal Na 3 B 4 O 7 I structure, completely analogous to Na 3 B 4 O 7 Br, which exists above 444 °C. [ABSTRACT FROM AUTHOR]

• A new hexagonal borate, Ag 12 (B 9 O 18)(NO 3) 3 , was studied. • The Ag 12 (B 9 O 18)(NO 3) 3 borate is the second example of compound with unique [B 9 O 18 ]9– groups. • Silver atoms show strongly anharmonic vibrations. Single crystals of a novel silver borate nitrate, Ag 12 (B 9 O 18)(NO 3) 3 (1), were produced as a byproduct upon preparation of Ag 3 B 6 O 10 (NO 3). 1 is hexagonal, (P 6 3 / m , a = 11.2896(3) Å, c = 11.6693(3) Å); its structure exhibits just a second example of unique [B 9 O 18 ]9– nonaborate anions [9B:6Δ3□:3(<2Δ□>–)<3□>] which can be described as three triborate groups linked in a large cycle. As commonly observed among silver borates, the Ag+ cations exhibit strongly anharmonic vibrations which were described using Gram–Chariler series up to 4th order. 1 is characterized by single-crystal X-ray diffraction, variable-temperature powder X-ray diffraction, IR, Raman, and UV–vis-NIR spectroscopy, complex thermal analysis, and DFT calculations. The thermal expansion of 1 is slightly anisotropic (α a = 15.0, α c = 17.7 × 10−6 °C−1 at 200 °C). Upon heating, the compound decomposes with formation of metallic silver and another borate, AgBO 2 , which could be earlier prepared only at high oxygen pressure. [ABSTRACT FROM AUTHOR]

Single crystals of two new quaternary bismuth oxychlorides, Bi 18 O 22 Cl 8.5 (BO 3) 0.5 (1) and Bi 18 O 22 Cl 8 Se (2) , have been serendipitously produced in syntheses starting from bismuth borate or oxyselenide and oxychloride. The crystal structure of 1 represents a high symmetry analog of the PbBi 17 O 22 Cl 9 type structure, formed by double aliovalent (Pb2+ → Bi3+, 0.5Cl– → 0.5BO 3 3−) substitution at the two respective cationic and anionic sites, while 2 is a full structural analog of PbBi 17 O 22 Cl 9. Overall, their structures can be described as sequences of thick (16 Å) slabs (2D "host" structure) comprised of litharge–like layers and ribbons formed by edge-sharing oxocentered OBi n , polyhedra (n = 4 and 5). The chloride anions fill the 7.6 Å channels with the triangular cross-section inside the slabs as well as the interlayer space wherein they are partially substituted by disordered BO 3 3− groups or Se2− anions. Compound 1 is just the second example of a mixed halide–borate occupancy among bismuth compounds while 2 illustrates much broader perspectives of mixed oxyhalide–oxychalcogenide approach to construction of novel complex bismuth compounds. Both compounds make new contributions to the family of tunnel structures of anion-centered tetrahedra featuring wide trigonal channels filled by halide anions or more complex metal–halide "salt inclusions". Topology of the channels in the tunnel bismuth oxychlorides. [Display omitted] • Single crystals of two new quaternary bismuth oxychlorides, Bi 18 O 22 Cl 8.5 (BO 3) 0.5 and Bi 18 O 22 Cl 8 Se were obtained and studied. • The crystal chemistry of microporous tunnel bismuth oxychlorides is discussed. • "The modularity of the channels and topologies are characterized," [ABSTRACT FROM AUTHOR]

Following the previously reported (enH2)[Co(H2PO3)2Cl2] (enH2 = ethylenediammonium cation), we successfully prepared its analogs with other divalent transition metal cations: Mn2+, Fe2+, Ni2+, and Cd2+. These compounds are isostructural to each other and the archetypic hydroselenites, (enH2)[M(HSeO3)2X2]. Despite evident similarities, some essential differences are observed between hydroselenites and hydrophosphites, both in chemistry and in structural details. Due to smaller size of H2PO3− relative to HSeO3−, only chloride phosphites could be prepared; the reducing capacity of H2PO3− permits preparation of FeII compound but not that of CuII. A single attempt to introduce piperazinediium cation instead of ethylenediammonium results in formation of (pipH2)[Co(H2PO3)2Cl2] with a structure different from (pipH2)[Cd(HSeO3)2Cl2]. Another serendipitous product is the 1-methylpiperazinediium derivative, (mpipH2)2[Co(H2PO3)2I3][H(H2PO3)2], which features a yet unique complex hydrogen-bonded network. [ABSTRACT FROM AUTHOR]

The fourth representative of the Pb 2 HgO 2 Cl 2 structure type, a novel oxybromide with the chemical formula Pb 2 CdO 2 Br 2 has been prepared via solid-state route and characterized by powder and single-crystal X-ray diffraction, and Raman and EDX spectroscopy. No analogs with M = Zn or X = I have been observed as yet, though chemical interaction takes place and some new compounds are likely to be produced. The peculiarities of chemical bonding within the Pb 2 M O 2 X 2 family (M = Cd, Hg; X = Cl, Br) are analyzed by DFT calculations. Most likely, the main factor restricting the number of representatives for the Pb 2 HgO 2 Cl 2 structure type is the size ratio of M 2+ and X −. [Display omitted] • A novel oxybromide, Pb 2 CdO 2 Br 2 with the Pb 2 HgO 2 Cl 2 type structure has been synthesized. • The chemical bonds in compounds Pb 2 M O 2 X 2 (M = Cd, Hg; X = Cl, Br) were analyzed by DFT calculations. • The crystal chemical features of compounds are discussed. [ABSTRACT FROM AUTHOR]

Our systematic explorations of the complex rare earth tellurite halide family have added several new [Ln12(TeO3)12][M6X24] (M = Cd, Mn, Co) representatives containing strongly deficient and disordered metal-halide layers based on transition metal cations. The degree of disorder increases sharply with decrease of M2+ radius and the size disagreements between the cationic [Ln12(TeO3)12]+12 and anionic [M6Cl24]−12 layers. From the crystal chemical viewpoint, this indicates that the families of both rare-earth selenites and tellurites can be further extended; one can expect formation of some more complex structure types, particularly among selenites. Analysis of the polytypism of compounds have been performed using the approach of OD ("order–disorder") theory. [ABSTRACT FROM AUTHOR]

Crystals of the rare-earth gallium borates R Ga 3 (BO 3 ) 4 , where R = Nd, Sm–Er, or Y, were grown by the flux method. The crystal structures of R Ga 3 (BO 3 ) 4 ( R = Eu, Ho) were studied on the basis of single-crystal X-ray diffraction measurements. The hexagonal unit-cell parameters are a = 9.4657(1) Å, c = 7.4667(1) Å and a = 9.4394(2) Å, c = 7.4322(1) Å for EuGa 3 (BO 3 ) 4 and HoGa 3 (BO 3 ) 4 , respectively, space group R 32. Structure model was determined by “charge flipping” method and refined to R = 1.93% [EuGa 3 (BO 3 ) 4 ] and R = 1.89% [HoGa 3 (BO 3 ) 4 ] in anisotropic approximation. All grown gallium borates were investigated by infrared (IR) spectroscopy technique in a middle and far IR region. IR spectra of rare-earth gallium borates correspond to a pure rhombohedral ( R 32) polytype structure. Small inclusions of a monoclinic phase were detected only in Eu and Nd compounds. Luminescence of Eu and Ho gallium borates was studied at room temperature. The measured decay times for the most intensive emission lines of EuGa 3 (BO 3 ) 4 (∼614 nm) and HoGa 3 (BO 3 ) 4 (434 nm) are 940 μs and 140 μs, respectively. The scheme of crystal-field energy levels of Eu 3+ in EuGa 3 (BO 3 ) 4 was built on the basis of the temperature-dependent optical transmission measurements combined with the luminescence data. The measured UV absorption edge for R Ga 3 (BO 3 ) 4 is at about 300 nm. [ABSTRACT FROM AUTHOR]

Sulfate anion plays an important role in the development of inorganic phosphors and is considered as the path for for the enhancement of the luminescent properties. The heterovalent [PO 4 ]3– → [SO 4 ]2– anion substitution in the β-Ca 3 (PO 4) 2 -type compounds was realized using the "ellestadite"-type strategy called by the analogy with the apatite-type structures. The novel compounds belonging to the Ca 10.5–0.5 x – y M y (PO 4) 7– x (SO 4) x , M = Ca2+, Mg2+ and Zn2+ series have been synthesized using high-temperature solid state reaction. The used isomorphous scheme was [PO 4 ]3– + ½ Ca2+ = [SO 4 ]2– + ½ □ with the formation of the vacancy for the charge compensation. The successful incorporation of [SO 4 ]2– groups was approved by Fourier-transform infrared spectroscopy, EDX method, and powder X-ray diffraction analysis. It was found that the sulfur atoms predominantly occupied T2 sites in the anionic sublattice according to crystal structure refinement based on the analysis of interatomic distances. The photoluminescent properties were studied for the Eu3+-doped samples and it was shown that Zn2+-containing samples exhibit a 1.5 times higher intensity in comparison with Mg2+-containing substituted phosphates. Thus, a new "ellestadite"-type substitution in β-Ca 3 (PO 4) 2 -type structure significantly expands the crystal chemistry and give more insights into the deeper understanding of the dependence of luminescent properties on the cation distribution. The pathways of the [SO 4 ]2– incorporation into the crystal structures are discussed in details. [ABSTRACT FROM AUTHOR]

Hydronium (oxonium) cation H3O+ plays an important role in mineralogy and mineral structures. However, it is rather difficult to detect it using conventional methods of crystal structure analysis. In particular, hydronium‐bearing eudialyte‐group minerals (EGMs) are well known. In this paper, we provide data on a low‐temperature X‐ray structure analysis and vibrationl spectroscopy study of previously described "potassium‐oxonium eudialyte" from the Khibiny alkaline massif (Kola Peninsula, Russia) as well as new data on vibrational spectra and hydrogen bonding of a series of sodium‐deficient hydrated EGMs including new samples and minerals whose crystal structures were investigated earlier. Based on single‐crystal X‐ray structural analysis and Raman spectroscopy, it is shown that natural sodium‐deficient hydrated zirconosilicates related to eudialyte contain different hydrated proton complexes with extremely strong hydrogen bonds. The data obtained have been compared with recent high‐level quantum electronic and vibrational calculations. Some hydrated proton complexes in hydrated eudialyte‐related minerals have Zundel‐ and Eigen‐type configurations with the O˙˙˙O distances of ~2.40 and ~2.55 Å, respectively. [ABSTRACT FROM AUTHOR]

The complexities of chemical composition and crystal structure are fundamental characteristics of minerals that have high relevance to the understanding of their stability, occurrence and evolution. This review summarises recent developments in the field of mineral complexity and outlines possible directions for its future elaboration. The database of structural and chemical complexity parameters of minerals is updated by H-correction of structures with unknown H positions and the inclusion of new data. The revised average complexity values (arithmetic means) for all minerals are 3.54(2) bits/atom and 345(10) bits/cell (based upon 4443 structure reports). The distributions of atomic information amounts, chemIG and strIG, versus the number of mineral species fit the normal modes, whereas the distributions of total complexities, chemIG,total and strIG,total, along with numbers of atoms per formula and per unit cell are log normal. The three most complex mineral species known today are ewingite, morrisonite and ilmajokite, all either discovered or structurally characterised within the last five years. The most important complexity-generating mechanisms in minerals are: (1) the presence of isolated large clusters; (2) the presence of large clusters linked together to form three-dimensional frameworks; (3) formation of complex three-dimensional modular frameworks; (4) formation of complex modular layers; (5) high hydration state in salts with complex heteropolyhedral units; and (6) formation of ordered superstructures of relatively simple structure types. The relations between symmetry and complexity are considered. The analysis of temporal dynamics of mineralogical discoveries since 1875 with the step of 25 years show the increasing chemical and structural complexities of human knowledge of the mineral kingdom in the history of mineralogy. In the Earth's history, both diversity and complexity of minerals experience dramatic increases associated with the formation of Earth's continental crust, initiation of plate tectonics and the Great Oxidation event. [ABSTRACT FROM AUTHOR]

In this work, we present a new borate, Ag 3 B 6 O 10 Br, as well as thermal properties of two recently reported members of M 3 B 6 O 10 X family, Ag 3 B 6 O 10 (NO 3) and Na 3 B 6 O 10 I. The structure of Ag 3 B 6 O 10 Br is non-centrosymmetric, Pnm 2 1 , and exhibits a new version of packing the ionic Ag–Br and covalent B–O frameworks. The non-centrosymmetry is induced by alternation of disordered and ordered borate "layers" normal to a. The Ag–Br sublattice is also strongly disordered and exhibits pronounced ahnarmonicity of thermal vibrations modeled using the Gram – Charlier series. Thermal behavior of Ag 3 B 6 O 10 Br, Ag 3 B 6 O 10 (NO 3) and Na 3 B 6 O 10 I was characterized using variable-temperature powder X-ray diffraction and thermal analysis. The thermal behavior of Ag 3 B 6 O 10 Br (α a = −0.5, α b = −7.4, α c = 41.5 at 200°С), Ag 3 B 6 O 10 (NO 3) (α a = 4.5, α b = 4.8, α c = 31.8 at 200°С), and Na 3 B 6 O 10 I (α a = 9.4, α b = −1.2, α c = 48.3 at 200°С) is strongly anisotropic due to the alignment of the hexaborate B 6 O 13 groups in the structure. [Display omitted] • A new non-centrosymmetric borate, Ag 3 B 6 O 10 Br was prepared. • Cationic [Ag 3 Br]3+sublattice shows strongly anharmonic displacement parameters. • Thermal expansion of Ag 3 B 6 O 10 X, X = Br, NO 3 , and Na 3 B 6 O 10 I is anisotropic. [ABSTRACT FROM AUTHOR]

An interaction of LnOCl and TeO 2 (Ln ​= ​Ce, Nd, Sm) in molten SrCl 2 results in a new family of layered quinary compounds, SrLn 4 (TeO 3) 4 Cl 6. Their monoclinic structures (P 2/ c) correspond to a novel structure type, build up by the alternation of [M 2 Ln 3 (TeO 3) 4 ] layers (M ​= ​Ln 0.5 Sr 0.5) and double halide sheets. New compounds are characterized by the modular type of the structures, while the presence of the twinning indicates the possible stacking disorder and polytypic character. An accurate analysis indicates that crystal structures belong to the OD ("order-disorder") family of category III with one types of nonpolar OD layers and can be described by the same OD family groupoid. Possible maximal degree order polytypes have been predicted and crystal chemical relationships among the oxyhalides of rare earth and lone-pair cations are briefly discussed. New compounds SrLn 4 (TeO 3) 4 Cl 6 (Ln ​= ​Ce, Nd, Sm) are characterized by layered OD ("order-disorder") structures with the corresponding twinning and polytypism. [Display omitted] • Single crystals of SrLn 4 (TeO 3) 4 Cl 6 (Ln ​= ​Ce, Nd, Sm) were synthesized. • The polytypism and OD-structures can be observed for these compounds. • The general features of the crystal chemistry and related tellurites are discussed in detail. [ABSTRACT FROM AUTHOR]

A series of Dy3+-doped MGd 9 (SiO 4) 6 O 2 :Dy3+ (M = Li, Na, K) phosphors that generated white emission were prepared using the high temperature solid-state technique. Simultaneously, the phase composition, crystal structure, electronic structure, as well as the luminescence properties of the as-prepared phosphors were investigated in detail. The structural refinement showed that the MGd 9 (SiO 4) 6 O 2 crystallized with the hexagonal apatite-type structure. The unit cell parameters increased gradually and the main peaks of the samples in XRD patterns shifted towards high angles with the substitution of alkali-metal ions (from Li+ to K+). Under the excitation of 350 nm, the as-obtained MGd 9 (SiO 4) 6 O 2 :Dy3+ phosphors gave bright white emission with the major emission peaks centering at 454, 477 and 573 nm. And the R y/b , CIE chromaticity coordinate and the corrected color temperature (CCT) of the phosphors were adjusted from 0.96, (0.3256, 0.3625) and 4602 K to 1.13, (0.3369, 0.3582) and 4201 K attributing to the substitution in the crystal structure. The thermoluminescence study of MGd 8.90 (SiO 4) 6 O 2 :0.10Dy3+ (M = Li, Na, K) showed good stability and the decay lifetimes of the samples were estimated to be about 470 μs. All the results suggested that the luminescence properties could be modified by the substitution of alkali metal ions, and the MGd 9 (SiO 4) 6 O 2 :Dy3+ (M = Li, Na, K) phosphors have potential application as white emission candidate for w -LEDs. • Novel Dy3+ doped apatite structure phosphors were successfully synthesized. • The symmetrical environment could be modified to a certain extent owing to substitution of alkali metal ions. • The DFT calculation was used to check the electronic structure. [ABSTRACT FROM AUTHOR]

Single crystals of four new potassium rare earth tellurite chlorides, [(Ln,K) 1- x Ln 11 (TeO 3) 12 ]K 6 Cl 16+ y (Ln = Pr, Sm, Gd, and Ho), have been prepared via molten salt synthesis. From the structural viewpoint, they belong to a numerous family of complex rare-earth (and Bi) selenite and tellurite halides featuring complex [(Ln,M) 12- x (ChO 3) 12 ] building blocks interleaving with various halide or metal-halide slabs. Similar to the formally isostructural Rb- and Cs-containing analogs, in the new series of nearly isostructural compounds, the [Ln 12- x (TeO 3) 12 ] slabs alternate with [K 6 Cl 16+ x ] counterparts derived from the CsCl archetype. We discuss the overall trends in the structural chemistry of these layered chalcogenite halides. [Display omitted] • Four new layered potassium rare earth tellurite chlorides have been synthesized. • The crystal structures have been refined. • The overall trends in the structural chemistry of these compounds are discussed. [ABSTRACT FROM AUTHOR]

A new triclinic layered borate, |Ag 4 Br|@[B 7 O 12 ], has been prepared by glass crystallization and slow cooling stoichiometric melts in evacuated silica ampoules. The structure is based upon a layered borate anion 7:∞2 [(4: 2Δ + 2 T) + (3: 2Δ + T)] with an architecture yet not observed among inorganic borates. The layers consist of two parts comprised of tri- and tetraborate groups; it is ∼7 Å thick and oriented parallel to (001). The interlayer space is filled by the cationic [Ag 4 Br]3+sublattice exhibiting disorder and anharmonicity at the silver sites. The new compound was characterized by thermal analysis, high-temperature powder X-ray diffraction, vibrational and UV–Vis–NIR spectroscopy, as well as DFT calculations. For the triclinic unit cell, the eigenvalues of the thermal expansion tensor and the orientation of the thermal expansion tensor relative to the crystallographic axes are determined. The thermal expansion of the new borate bromide is strongly anisotropic, being marginal in the plane of the B–O layers (α 11 = 8.2 (1), α 22 = 4.71 (3) × 10−6 °С−1) while quite large in the normal direction (α 33 = 38.2 (3) × 10−6). [Display omitted] • A new triclinic layered borate,.|Ag 4 Br|@[B 7 O 12 ] was studied • Crystal structure is based upon a new layered borate anion. • Cationic [Ag 4 Br]3+sublattice shows strongly anharmonic vibrations. • Thermal expansion is strongly anisotropic. [ABSTRACT FROM AUTHOR]

Series of Tb3+-doped phosphates Ca 9– x Zn x Tb(PO 4) 7 and Ca 9– x Zn x La 0.99 (PO 4) 7 :0.01 Tb3+ with β-Ca 3 (PO 4) 2 -type structure were synthesized using a standard high temperature route. The luminescence properties of these compounds were determined by the photoluminescence emission (PL), the excitation (PLE) spectra and lifetime measurements. A green-emitting LED device was fabricated using the most effective one. No concentration quenching was detected in the whole region of solid solutions. Upon Ca2+ → Zn2+ substitution the crystal structure transformation from the polar to centrosymmetric. The ways of control the PL spectra and cross-relaxation process were determined. In both solid solutions a "green" magneto-dipole 5D 4 → 7F 5 transition is predominant. The integral intensity increases in 3 times in the most effective Ca 8 ZnTb(PO 4) 7 phosphor. The measured quantum yields (QY) reached 31%. Thus, a target substitution of Ca2+ by Zn2+ is a new path for crystal site engineering and allows to obtain an efficient green luminescence of Tb3+ ions in the β-Ca 3 (PO 4) 2 -type hosts. • The series of phosphates Ca 9– x Zn x Tb(PO 4) 7 and Ca 9– x Zn x La(PO 4) 7 :Tb3+ were synthesized and studied. • The integral intensity increases in 3 times. • The Quantum Yield reached 31% in Ca 8 ZnTb(PO 4) 7. [ABSTRACT FROM AUTHOR]

A new cubic borate, Yb 3 [BO 3 (OH) 6 ⋅2.1H 2 O was synthesized in a multi-component hydrothermal system Yb 2 (CO 3) 3 : B 2 O 3 : P 2 O 5 = 5 : 2: 1 (T = 280 °C; P = 90–100 atm; pH = 3). The crystal structure was studied using single crystal X-ray analysis. The structure has been refined in the space group I 432, possesses the unit cell parameter a = 12.2808(15) Å. A microporous positively charged framework is formed by predominant Yb cations coordinated by O2−, OH− as a tetragonal antiprism, which are linked together via common edges and vertices. The extra framework BO 3 triangles center narrow channels, directed along 3-fold axis, are perpendicular to them and clamped between large Yb polyhedra. The large cavities with the effective cavity width 7.7 Å are filled by disordered water molecules. The crystal chemical formula could be written as (Z = 8): |(BO 3)(H 2 O) 2.1 |[Yb 3 (OH) 6. A topological analysis was performed using the ToposPro software. The framework is characterized by the following tile sequence: [34 6 [324.46.68; the calculated structural complexity parameters are: v = 48 atoms, I G = 1.500 bits/atom, and I G,total = 72.000 bits/unit cell; the framework density is 12.96 Yb/1000 Å3. The Yb-borate is similar to the tetragonal compounds with the general formula ABa 12 (BO 3) 7 F 4 (A = Li, Na) and Li x Na 1-x Ba 12 (BO 3) 7 F 4 , which are characterized by co-called "anti-zeolite" frameworks, formed by Ba2+ cations. The excess of water in the structure of the new borate compound Yb 3 [BO 3 (OH) 6 ⋅2.1H 2 O is determined by its zeolitic nature and by hydrothermal growth conditions. Image 1 • A new cubic borate Yb 3 [BO 3 (OH) 6 ⋅2.1H 2 O was synthesized hydrothermally. • Anionic part is presented by isolated BO 3 triangles. • Yb atoms form a microporous cationic positively charged "anti-zeolite" framework. • Water molecules fill large cavities of width 7.7 Å connected by channels. [ABSTRACT FROM AUTHOR]

A solid state route was used for the preparation of whitlockite-type solid solutions Ca 9 Y(NbO 4) x (VO 4) 7– x and Ca 9+0.5 x Yb (GeO 4) x (VO 4) 7– х in both powder and ceramic forms. The complex of methods, including synchrotron powder diffraction, were applied for the characterization of the first-time obtained compounds. The limits of the anionic substitution were found up to х = 0.28 (Nb) and 0.35 (Ge). The synthesized solid solutions show ferroelectric properties. The Curie temperatures T c were determined and gradually rise with x. The increase of T c correlates with the enlargement of tetrahedral units upon Nb5+ or Ge4+ substitutions for V5+ cations. The intensity of optical second harmonic generation (SHG) induced by a Nd:YAG laser depends non-monotonically on the grain size in powder Ca 9 Y(NbO 4) x (VO 4) 7– x samples, marking the length of the phase matching l c = 15 μm for x = 0.28 in comparison with l c = 9.14 μm in Ca 9 Y(VO 4) 7. Manifold increase in the SHG intensity in both solid solutions is partly related to the appearance of more polarizable Nb5+ and Ge4+ cations in the E1O 4 tetrahedra on the 3-fold axis, resulting in an enlarged birefringence of the materials. The photoluminescence study of the Ca 9+0.5 x Yb(GeO 4) x (VO 4) 7– х reveals the same environment of the Yb3+ ions all alone the solid solution. The intensity of the luminescence rises with germanium substitution for vanadium about 2 times. Ca 9 Y(NbO 4) x (VO 4) 7– x and Ca 9+0.5 x Yb(VO 4) 7– х (GeO 4) x solid solutions were synthesized for the first time and characterized in detail using different techniques. The crystal structures were solved and refined based on powder synchrotron data, ferroelectric phase transitions were observed, and luminescent properties were measured. The substitution of V4+ in tetrahedra by Ge4+ or Nb5+ cations in the host structure leads to the considerable improvement of the non-linear optical properties. Image 1 • New whitlockite-type solid solutions Ca 9 Y(NbO 4) x (VO 4) 7– x and Ca 9+0.5 x Yb(VO 4) 7– х (GeO 4) x were synthesized. • The crystal structures were refined based on powder synchrotron data, ferroelectric phase transitions and luminescent properties were studied. • The substitution of V4+ by Ge4+ or Nb5+ leads to the considerable improvement of the non-linear optical properties. [ABSTRACT FROM AUTHOR]

The ionic liquid 1-ethyl-3-methylimidazolium diethyl phosphate (EMIM-Et 2 PO 4) was used in the synthesis of four new hybrid organic-inorganic uranyl phosphates. The structure of (UO 2)[PO 2 (OC 2 H 5) 2 ] 2 (1) is triclinic, P -1, a = 5.374(3) Å, b = 7.674(4) Å, c = 11.132(6) Å, α = 105.333(6)°, β = 90.562(6)°, γ = 98.269(6)°, Z = 4. The structure of (C 6 N 2 H 11){(UO 2) 2 (NO 3) 2 [PO 2 (OC 2 H 5) 2 ] 3 } (2) is triclinic, P -1, a = 9.316(3) Å, b = 11.890(4) Å, c = 18.477(7) Å, α = 91.197(4)°, β = 102.993(4)°, γ = 102.625(4)°, Z = 2. The structure of {(UO 2)(H 2 O)[PO 2 (OC 2 H 5) 2 ] 2 } (3) is monoclinic, P 2 1 / c , a = 9.2005(7) Å, b = 10.1531(8) Å, c = 18.5968(14) Å, β = 99.6447(9)°, Z = 4. The structure of (C 6 N 2 H 11){(UO 2) 2 [PO 2 (OC 2 H 5) 2 ] 3 (PO 3 OC 2 H 5)} (4) is monoclinic, C 2/ c , a = 36.048(10) Å, b = 13.553(4) Å, c = 18.583(5) Å, β = 119.454(3)°, Z = 8. The variable reactants, thermal conditions, and crystallization times resulted in diverse topologies unique to uranyl phosphate chain (1 and 2) and sheet (3 and 4) structures. Four new uranyl phosphate compounds were synthesized using the ionic liquid 1-ethyl-3-methylimidazolium diethyl phosphate. The organic ethyl groups of the phosphate stabilized structures unique to uranyl phosphate chemistry, and the imidazolium cations provided charge balance where required. Image 1 [ABSTRACT FROM AUTHOR]

This review contains data on a wide class of microporous materials with frameworks belonging to the sodalite topological type. Various methods for the synthesis of these materials, their structural and crystal chemical features, as well as physical and chemical properties are discussed. Specific properties of sodalite-related materials make it possible to consider they as thermally stable ionic conductors, catalysts and catalyst carriers, sorbents, ion exchangers for water purification, matrices for the immobilization of radionuclides and heavy metals, hydrogen and methane storage, and stabilization of chromophores and phosphors. It has been shown that the diversity of properties of sodalite-type materials is associated with the chemical diversity of their frameworks and extra-framework components, as well as with the high elasticity of the framework., Competing Interests: The authors declare no conflict of interest.

Single crystals of two new intermetallic phases Sm 2 Mn 1- x Ga 6- y Ge y ( x = 0.1-0.3, y = 0.6-1.0) and Sm 4 MnGa 12- y Ge y ( y = 3.0-3.5) were grown using a self-flux technique. According to single crystal X-ray diffraction data, Sm 4 MnGa 12- y Ge y is characterised by the Y 4 PdGa 12 structure type ( a ∼ 8.65 Å; Im 3̄ m ), while Sm 2 Mn 1- x Ga 6- y Ge y formally adopts the K 2 PtCl 6 structure type ( a ∼ 8.71 Å; Fm 3̄ m ). The general features of both compounds with rather similar crystal structures are represented by the alternation of empty and Mn-filled p-element octahedra, the order of which is determined by the Mn concentration. The diffraction data for Sm 2 Mn 1- x Ga 6- y Ge y reveal a large concentration of Mn vacancies ( x ∼ 0.3), which affects adjacent Ga/Ge atoms leading to their shift towards the vacancy. Both compounds demonstrate two ferromagnetic-like transitions and the presence of two interacting Mn and Sm magnetic sublattices. The Mn sublattice orders at T C1 of 143 K and 318 K, while the Sm one orders at lower temperatures at T C2 of 50 K and 280 K for Sm 4 MnGa 8.6 Ge 3.4 and Sm 2 Mn 0.74 Ga 5.1 Ge 0.9 , respectively. The increase in Mn content not only increases the ordering temperatures, but also dramatically decreases the coercivity μ 0 H C from 230 mT to just 6.5 mT at 2 K. Despite the presence of two magnetically active sublattices in Sm 2 Mn 0.74 Ga 5.1 Ge 0.9 , the magnetic entropy change is quite low and only reaches 0.3 J kg -1 K -1 at T = 300 K and μ 0 H = 5 T, while the estimated relative cooling power (RCP) is about 36 J kg -1 at 5 T.

β-Tricalcium phosphate (β-TCP) is widely used as bone implant material. It has been observed that doping the β-TCP structure with certain cations can help in combating bacteria and pathogenic microorganisms. Previous literature investigations have focused on tricalcium phosphate structures with silver, copper, zinc, and iron cations. However, there are limited studies available on the biological properties of β-TCP containing nickel and cobalt ions. In this work, Ca 10.5- x Ni x (PO 4 ) 7 and Ca 10.5- x Co x (PO 4 ) 7 solid solutions with the β-Ca 3 (PO 4 ) 2 structure were synthesized by a high-temperature solid-state reaction. Structural studies revealed the β-TCP structure becomes saturated at 9.5 mol/% for Co 2+ or Ni 2+ ions. Beyond this saturation point, Ni 2+ and Co 2+ ions form impurity phases after complete occupying of the octahedral M5 site. The incorporation of these ions into the β-TCP crystal structure delays the phase transition to the α-TCP phase and stabilizes the structure as the temperature increases. Biocompatibility tests conducted on adipose tissue-derived mesenchymal stem cells (aMSC) using the (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) (MTT) assay showed that all prepared samples did not exhibit cytotoxic effects. Furthermore, there was no inhibition of cell differentiation into the osteogenic lineage. Antibacterial properties were studied on the C. albicans fungus and on E. coli , E. faecalis , S. aureus, and P. aeruginosa bacteria strains. The Ni- and Co-doped β-TCP series exhibited varying degrees of bacterial growth inhibition depending on the doping ion concentration and the specific bacteria strain or fungus. The combination of antibacterial activity and cell-friendly properties makes these phosphates promising candidates for anti-infection bone substitute materials.

A new series of Sr-based phosphates, Sr 9- x Mn x Eu(PO 4 ) 7 , were synthesized using the high-temperature solid-state method in air. It was found that these compounds have the same structure as strontiowhitlockite, which is a β-Ca 3 (PO 4 ) 2 (or β-TCP) structure. The concentration of Mn 2+ ions required to form a pure strontiowhitlockite phase was determined. An unusual partial reduction of Eu 3+ to Eu 2+ in air was observed and confirmed by photoluminescence (PL) and electron spin resonance (ESR) spectra measurements. The PL spectra recorded under 370 nm excitation showed transitions of both 4 f 5 d -4 f Eu 2+ and 4 f -4 f Eu 3+ . The total integral intensity of the PL spectra, monitored at 395 nm, decreased with increasing Mn 2+ concentration due to quenching effect of Eu 3+ by the Mn 2+ levels. The temperature dependence of Eu 2+ photoluminescence in a Sr 9- x Mn x Eu(PO 4 ) 7 host was investigated. The conditions for the reduction of Eu 3+ to Eu 2+ in air were discussed.

VO and VO 2 vanadyl groups with short (typically 1.57-1.68 Å), essentially covalent, V-O bonds are common for V 4+ -bearing oxysalts with [5]- and [6]-coordinated vanadium. There is a clear negative correlation between vanadyl bond lengths and wavenumbers of the bands of V-O stretching vibrations in infrared spectra (in the range 1000-880 cm -1 ). Optical, structural and chemical data for vanadyl minerals are used to calculate Gladstone-Dale compatibility coefficients. Gladstone-Dale compatibility indices of minerals containing vanadyl bonds are compared with total electronic polarizabilities of V 4+ . Unlike compounds of [5]-coordinated Ti 4+ , for most minerals with V 4+ =O (vanadyl) bonds there is good agreement between measured refractive indices and those calculated based on the polarizability concept.

The study of azoproite by Biryukov et al. [Acta Cryst. (2022), B78, 809-816) continues the systematic and complex investigation of the crystal structures, temperature behavior and magnetic properties of natural oxoborates.

Compounds with the general formula Ln 3+ (SeO 3 )(HSeO 3 )·2H 2 O, where Ln = Sm 3+ , Tb 3+ , Nd 3+ and Lu 3+ , are characterized by orthorhombic symmetry with space group P2 1 2 1 2 1 and unit-cell parameters in the ranges a ∼ 6.473-6.999, b ∼ 6.845-7.101, c ∼ 16.242-16.426 Å. Light-purple irregularly shaped crystals of a new monoclinic polytype of neodymium selenite Nd(SeO 3 )(HSeO 3 )·2H 2 O have been obtained during a mild-condition hydrothermal synthesis. The monoclinic unit-cell parameters are: a = 7.0815 (2), b = 6.6996 (2), c = 16.7734 (5) Å, β = 101.256 (1)°, V = 780.48 (6) Å 3 ; space group P2 1 /c. The crystal structures of Nd(SeO 3 )(HSeO 3 )·2H 2 O polymorphs show order-disorder (OD) character and can be described using the same OD groupoid family, more precisely a family of OD structures built up from two kinds of non-polar layers (category IV). The first monoclinic maximum degree order (MDO) structure (MDO1-polytype) with space group P2 1 /c can be obtained when the inversion centre is active in the L 2n -type layers, while the second MDO structure (MDO2-polytype) is orthorhombic with space group P2 1 2 1 2 1 and can be obtained when the [2 1 --] operation is active in the L 2n -type layers. The structural complexity parameters and DFT calculations of both polytypes show that the polytype structures are extremely close energy-wise and almost equally viable from the point of total energy of the structure.

Most known compounds with five-coordinated Ti 4+ are natural and synthetic titanosilicates. The crystal structure of natural fresnoite, Ba 2 TiSi 2 O 8 [tetragonal, space group P4bm, a = 8.510 (1) Å, c = 5.197 (1) Å, V = 376.4 (1) Å 3 , Z = 2], has been refined to R = 0.011 on the basis of 807 unique single-crystal reflections with I > 2σ(I). Titanium has fivefold coordination with one short (`titanyl') bond of 1.692 (5) Å. Bonds in the TiO 5 polyhedron are discussed in comparison to analogous coordination polyhedra in other minerals and compounds. A review of all known compounds with Ti 4+ O 5 polyhedra shows that most of them are titanosilicates in which titanium forms a short Ti-O bond (∼1.61 to ∼1.77 Å). Poor Gladstone-Dale compatibility between chemical composition, optical characteristics and density of these compounds is explained by the anomalous contribution of [5] Ti 4+ to the optical properties as shown by calculations based on the relationship between electronic polarizabilities and refractive indices. An improved Gladstone-Dale coefficient of 0.29 is suggested for TiO 2 with [5] Ti 4+ . A negative correlation between `titanyl' bond lengths and wavenumbers of the bands of Ti-O stretching vibrations (in the range of 890-830 cm -1 ) in infrared and Raman spectra is observed.

The identification of the framework type in multilayer cancrinite- and sodalite-group minerals and synthetic compounds is predominantly based on the unit-cell dimensions determined from powder or single-crystal X-ray diffraction data, by analogy with previously characterized samples with known crystal structures. However, topological type of the framework cannot be reliably determined in this way because of the different possible ABC staking sequences and different sets of cages with the same number of layers in the repeat unit. To solve this problem, additional criteria are required. The use of infrared (IR) spectroscopy makes it possible to distinguish topologically different types with the same unit-cell parameters. The most important diagnostic range in the IR spectrum (the "finger-print region", from 510 to 760 cm -1 ) corresponds to the O-T-O bending vibrations (T = Si, Al). The spectral bands at 705 ± 8, 528 ± 5, 547 ± 4, and 555 ± 3 cm -1 indicate the presence of the sodalite, Losod, liottite, and giuseppettite cages, respectively. The band at 528 ± 5 cm -1 shifts towards ∼518 cm -1 in the case when Losod cage hosts carbonate group. The IR spectrum in the "finger-print region" can be also used to identify a mineral species belonging to two-layer or three-layer minerals with different extra-framework compositions. The wavenumber of the antisymmetric stretching mode of the 12 CO 2 molecule, which is a common admixed extra-framework constituent in minerals belonging to the cancrinite and sodalite groups, depends on the kind of the host cage or channel: 2340-2343 cm -1 for the sodalite cage, 2338 cm -1 for the Losod cage, and 2351-2353 cm -1 for the liottite cage and wide channel in the cancrinite-type framework., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Using glass crystallization and solid-state techniques, we were able to complete the family of salt-inclusion silver halide borates, Ag 4 B 7 O 12 X, by the X = Cl and I members. The new compounds are characterized by differential scanning calorimetry, single-crystal and high-temperature powder X-ray diffraction, optical spectroscopy, and density functional theory calculations. In all structures, the silver atoms exhibit strong anharmonicity of thermal vibrations, which could be modeled using Gram-Charlier expansion, and its asymmetry was characterized by the skewness vector. The topology of the silver halide and borate sublattices has been analyzed separately for the first time. Along the I → Br → Cl series, we observe a decrease of the melting point and configuration entropy and an increase of thermal expansion and its anisotropy and thermal vibration anharmonicity, which indicates decreasing stability.

The series of β-Ca 3 (PO 4 ) 2 -type phosphors Ca 9.5-1.5 x MgEu x (PO 4 ) 7 were synthesized by a solid-state route. Observation of the proper Eu 3+ ion distribution in the Ca 9.5 Mg(PO 4 ) 7 host matrix was made by a direct method using 151 Eu Mössbauer spectroscopy in combination with X-ray analysis and dielectric and luminescent spectroscopy. The photoluminescence properties were studied in detail. The samples exhibit an exceptionally narrow-band red emission according to the dominant 5 D 0 → 7 F 2 transition and fulfill the industrial requirements for high-energy-efficiency red phosphors. The contribution of Eu 3+ ions in different crystal sites to the luminescent properties is discussed in detail. The difference of the excitation of Eu 3+ in the M1 and M2 sites was revealed by photoluminescence excitation spectra in accordance with structure refinement. The temperature dependence of the luminescence intensity was studied. Different tendencies in the thermal behavior of emission lines allow one to consider the studied compounds as phosphors suitable for luminescence thermometry. The measured quantum yield for Ca 9.5-1.5 x MgEu x (PO 4 ) 7 shows excellent results and reaches 63%.

Two uranium(IV) sulfate framework compounds were crystallized at room temperature from aqueous solutions containing uranyl ions by photochemical reduction in the presence of 2-propanol. U 3 H 2 (SO 4 ) 7 (H 2 O) 5 ·3H 2 O ( 1 ) crystallizes in space group P 6 5 with a = 9.3052(17) Å, c = 53.515(10) Å, V = 4012.9(13) Å 3 , and Z = 6, and U 3 (UO 2 ) 0.2 (SO 4 ) 6 (OH) 0.4 ·2.3H 2 O ( 2 ) is tetragonal, with space group P 4 2 / nmc , a = 25.624(3) Å, c = 8.9435(10) Å, V = 5872.2(11) Å 3 , and Z = 8. The structures of 1 and 2 are the most complex among uranium(IV) sulfates.

Single crystals of Rb 2 CaCu 6 (PO 4 ) 4 O 2 were synthesized by a hydrothermal method in the multicomponent system CuCl 2 -Ca(OH) 2 -RbCl-B 2 O 3 -Rb 3 PO 4 . The synthesis was carried out in the temperature range from 690 to 700 K and at the general pressure of 480-500 atm [1 atm = 101.325 kPa] from the mixture in the molar ratio 2CuO:CaO:Rb 2 O:B 2 O 3 :P 2 O 5 . The crystals studied by single-crystal X-ray analysis were found to be monoclinic, space group C2, a = 16.8913 (4), b = 5.6406 (1), c = 8.3591 (3) Å, β = 93.919 (3)°, V = 794.57 (4) Å 3 . The crystal structure of Rb 2 CaCu 6 (PO 4 ) 4 O 2 is similar to that of shchurovskyite and dmisokolovite and is based upon a heteropolyhedral open framework formed by polar layers of copper polyhedra linked via isolated PO 4 tetrahedra. The presence of well-isolated 2D heteropolyhedral layers in the title compound suggests low-dimensional magnetic behavior which is masked, however, by the fierce competition between multiple ferromagnetic and antiferromagnetic exchange interactions. At T C = 25 K, Rb 2 CaCu 6 (PO 4 ) 4 O 2 reaches a magnetically ordered state with large residual magnetization.

The bismuth(III) oxophosphate Bi 3 (PO 4 )O 3 was obtained by hydrothermal synthesis. The unit cell has a = 5.6840(6) Å, b = 7.0334(7) Å, c = 9.1578(9) Å, α = 78.958(2)°, β = 77.858(2)°, γ = 68.992(2)°, V = 331.41(6) Å 3 , space group P1̅, and Z = 2. The crystal chemical formula that reflects the presence of oxo-centered tetrahedra and triangles is 2D [O III O IV 2 Bi 3 ](PO 4 ). The crystal structure contains [O 3 Bi 3 ] 3+ ∞∞ -heteropolyhedral corrugated layers parallel to (001), which alternate along [001] with isolated (PO 4 ) tetrahedra. The structural complexity parameters are v = 22 atoms, I G = 3.459 bits/atoms, and I G,total = 76.107 bits/unit cell, and thus Bi 3 (PO 4 )O 3 is the simplest pure bismuth(III) oxophosphate.

A hydroxyl-dominant analogue of gadolinite-(Y) (OH-Gad) has been discovered in the Heftetjern granitic pegmatite, southern Norway, in association with late-stage rare-earth-element containing minerals. The empirical formula, based on ten O atoms per formula unit, is (Y 1.285 Ca 0.55 Ce 0.07 La 0.04 Nd 0.01 ) Σ1.955 (Fe 2+ 0.57 □ 0.43 )Be 2.02 Si 1.995 O 8.48 (OH) 1.52 . The mineral is monoclinic, space group P2 1 /c, a = 4.7514 (10), b = 7.5719 (16), c = 9.9414 (2) Å, β = 90.015 (4)°, V = 357.663 (3) Å 3 and Z = 2. The density calculated using the empirical formula is 3.903 g cm -3 . The crystal structure was refined to R = 0.0217 for 776 reflections with I > 2σ(I). OH-Gad is isostructural with gadolinite-(Y) and it is characterized by the predominance of OH - over O 2- at the anionic Ø-site. The refined crystal-chemical formula is: A (Y 1.25 Ca 0.55 Ce 0.2 ) X (Fe 2+ 0.57 □ 0.43 ) Z Be 2 T Si 2 O 8 Ø [(OH) 0.86 O 0.59 (OH)* 0.55 ] (Z = 2). The possible orientation and local environment of the hydroxyl group were suggested based on bond-valence sum calculations and geometrical analysis of the crystal structure. The infrared spectrum confirms disordering of H atoms. OH-Gad seems to be a potentially new mineral, the first simultaneously hydroxyl- and iron-dominant member of the gadolinite subgroup. It is an OH-analogue of gadolinite-(Y) and an Fe 2+ -analogue of hingganite-(Y).