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Using the additional parameter pressure (Walker-type multianvil device), the lead(II) oxidotellurate(VI) PbTeO4 was synthesized at conditions of 8 GPa and 750 °C, and for the first time its crystal structure was determined using single-crystal X-ray diffraction data. PbTeO4 crystallizes with four formula units in the monoclinic space group I2/a with unit cell parameters a = 5.4142(4), b = 4.9471(4), c = 12.0437(11) Å, β = 99.603(3)°, and V = 318.07(5) Å3. UV-Vis measurements revealed UV transparency down to 200 nm. From the diffuse reflectance data experimental band gaps (Eg(direct) = 2.9 eV/Eg(indirect) = 2.8 eV) were determined and compared with calculated values. Temperature-dependent X-ray powder diffraction and complementary thermal analysis measurements revealed a stability range of PbTeO4 up to 625 °C. Additionally, theoretical calculations at DFT level of theory were carried out to obtain the electronic band structure, X-ray powder diffraction patterns, IR/Raman vibrational spectra and Mulliken partial charges. The electron localization function (ELF) was visualized to emphasize the presence of the electron lone pair E in the coordination sphere of the PbII atom. [ABSTRACT FROM AUTHOR]

A hitherto unknown modification of I2O5 was obtained from high‐pressure/high‐temperature syntheses in a Walker‐type multianvil device at 8 GPa and 250 °C. HP‐I2O5 crystallizes in the monoclinic crystal system with space group P21/c (no. 14) with the unit cell parameters a=12.0612(3) Å, b=4.8613(2) Å, c=6.9585(2) Å, β=100.10(1)° (at 173 K), and four formula units per cell. The single‐crystal structure data are accompanied by powder X‐ray diffraction data at ambient and elevated temperatures. Furthermore, DFT calculations were carried out to investigate the phase transition between the ambient‐pressure polymorph NP‐I2O5 to the newly synthesized high‐pressure phase. [ABSTRACT FROM AUTHOR]

AlB4O6N, Al0.97Cr0.03B4O6N, and Al0.83Cr0.17B4O6N are the first representatives of the recently established structure‐family of oxonitridoborates containing Al3+. These compounds are isotypic to CrB4O6N and are synthesized in a multi‐anvil press under high‐pressure/high‐temperature conditions of 7.0 GPa/1350 °C. Structural refinement by single‐crystal X‐ray diffraction shows that they crystallize in the space group P63mc (no. 186) with two formula units per cell. Detailed characterization including high‐temperature X‐ray powder diffraction (HT‐XRD), electron probe microanalysis (EPMA), measurements of second harmonic generation (SHG), hardness, photoluminescence properties, vibrational spectroscopy, and band structure calculations reveal intriguing physicochemical properties that strongly resemble the famous material ruby. [ABSTRACT FROM AUTHOR]

We report on the synthesis, structure determination, and characterization of a new series of compounds LnCdB6O10(OH)3 (Ln = Sm–Er). Syntheses were carried out in a Walker-type multianvil device at 7 GPa and 650 °C. Structure determinations revealed the coexistence of an orthorhombic and a monoclinic polymorph, depending on the ionic radius of the lanthanoid cation. The orthorhombic structural variants crystallize non-centrosymmetrically in the space group Pna21 (no. 33), while the monoclinic modifications crystallize in space group P21/c (no. 14). Both modifications display a layered crystal structure built up by a repeating [B6O13]8− building block as their main structural feature. [ABSTRACT FROM AUTHOR]

The orthorhombic phases LaB3.6O7 and PrB3.6O7 were obtained by high‐pressure/high‐temperature syntheses at 11 GPa and temperatures of 1130 °C (LaB3.6O7) as well as 850 °C (PrB3.6O7) using a modified Walker‐type multianvil apparatus. The title compounds crystallize in the space group Pmn21 (no. 31) exhibiting a defective α‐SrB4O7 structure variant with the unit cell parameters a=10.4551(3) Å, b=4.4562(1) Å, c=4.2973(1) Å for LaB3.6O7 and a=10.4305(3) Å, b=4.4257(1) Å, c=4.2815(1) Å for PrB3.6O7. Both compounds were characterized by powder/single‐crystal X‐ray diffraction, vibrational spectroscopy, second harmonic generation, and electron dispersive X‐ray spectroscopy measurements. [ABSTRACT FROM AUTHOR]

LixMoS2 is not only a lithium battery material, but is also an important precursor for the synthesis of MoS2 nanomaterials. Current syntheses of MoS2, such as in n‐butyllithium/LiBH4 or electrochemically, are not satisfying in terms of defined stoichiometry and crystallinity, so an accurate experimental crystal structure determination of this important and widely used material has been long awaited. A high‐pressure/high‐temperature synthesis yielded highly crystalline 1T′′‐LixMoS2 (x=1, 1.333). 1T′′‐LiMoS2 crystallizes in the space group P1‾ $\bar 1$ with a=6.2482(3) Å, b=6.6336(3) Å, c=6.7480(3) Å, α=119.321(2)°, β=90.010(2)° and γ=90.077(2)°. The arrangement of Mo atoms within the b‐c‐plane confirmed a predicted Peierls distortion. A similar atom distribution pattern to that of Mo is also observed for the lithium atoms. Calculation of bond valence site energies gave an activation barrier of 1.244 eV for 2D lithium‐ion migration. For x=1.333, a phase‐pure synthesis was achieved. [ABSTRACT FROM AUTHOR]

Tm2CrB3O9 was obtained by high-pressure/high-temperature syntheses at 7.5 GPa and 850 °C. The compound crystallizes homeotypically to walstromite in the triclinic space group P 1 ¯ (no. 2) with the unit cell parameters a = 5.9118(4) Å, b = 5.9148(4) Å, c = 8.3575(6) Å, α = 83.64(1)°, β = 71.19(1)°, and γ = 79.93(1)°, and two formula units per cell. Single-crystal and powder diffraction data are accompanied by an infrared spectroscopic investigation and the structural features of this new compound are discussed in detail. [ABSTRACT FROM AUTHOR]

The compounds Li6MoN4 and Li6WN4 were prepared from the reactants M (M = Mo, W) and Li3N in a radiofrequency furnace at 1000 °C. The lithonitridometallates crystallize in the tetragonal system with the lattice parameters: a = 6.6844(1), c = 4.9294(1) Å for Li6WN4 based on single-crystal X-ray diffraction data and a = 6.6611(3), c = 4.9338(3) Å for Li6MoN4 taken from powder X-ray diffraction data. Colorless to slightly reddish single-crystals of the tungsten compound were isolated and the crystal structure was refined in the space group P42/nmc (no. 137) with Z = 2 and the powder X-ray data of the molybdenum compound were analyzed by a Rietveld refinement. Both structures belong to the Li6[ZnO4] type published by Hoppe et al. in 1987 (Untenecker H., Hoppe R. Z. Anorg. Allg. Chem. 1987, 551, 147–150) and could be doped with Ce3+ for the first time. The investigated compounds show a reddish color impression upon UV to blue irradiation and exhibit a broad emission band with a maximum at λmax = 693 nm (fwhm 97 nm) for Li6MoN4 and at λmax = 653 nm (fwhm 133 nm) for Li6WN4. [ABSTRACT FROM AUTHOR]

Using high-pressure/high-temperature synthesis methods, it was possible to increase the number of known borates with a crystal structure derived from gadolinite. Syntheses of Tb2Co(B2O5)2 (8 GPa, 1000 °C) and Tb2Cu(B2O5)2 (11 GPa, 650 °C) were carried out in a Walker-type multianvil device. The crystal structures were determined by single-crystal X-ray diffraction methods and Rietveld refinements of the powder patterns. The new compounds were further characterized by their infrared spectra. The lanthanoid cobalt and copper borates Tb2Co(B2O5)2 and Tb2Cu(B2O5)2 crystallize in the monoclinic space group P21/c (no. 14) with the unit cell parameters a = 4.5630(1), b = 7.2991(2), c = 9.4161(2) Å, and β = 91.14(1)° for the cobalt and a = 4.5757(1), b = 7.3078(2), c = 9.3771(3) Å, β = 90.73(1)° for the copper compound. [ABSTRACT FROM AUTHOR]

Building on studies of monoclinic Li3SiNO2, a polymorph, β-Li3SiNO2, with a previously unknown structure type was synthesized. The β-phase crystallizes in the orthorhombic space group Pbca (no. 61) with lattice parameters of a = 18.736(2), b = 11.1267(5), c = 5.0897(3) Å, and a cell volume of V = 1057.2(1) Å3. Using high-temperature solid-state reactions in sealed tantalum tubes, it was possible to obtain high purity samples (<5 wt% of side phase LiSi2N3 according to Rietveld analysis) containing exclusively one or the other polymorph, depending solely on the cooling rate. In contrast to the monoclinic phase, orthorhombic β-Li3SiNO2 additionally contains a third layer and shows a layer-sequence of the type ABCB. Doped with the activator ion Eu2+, the new polymorph exhibits an intense yellow emission (λmax = 586 nm, fwhm = 89 nm, 0.33 eV, 2650 cm−1) under irradiation with UV to blue light. Hence, the structural difference between the two polymorphs goes along with a significant blue-shift of 16 nm. The results from single-crystal diffraction and single-grain luminescence measurements were confirmed by Rietveld analysis of bulk samples and powder luminescence data. [ABSTRACT FROM AUTHOR]

At multianvil high-pressure/high-temperature conditions of 10 GPa and 1273 K, the first ternary tungsten tellurate WTe2O7 is formed, starting from a stoichiometric mixture of WO3 and TeO2. The compound crystallizes triclinic in a hitherto unknown crystal structure type with the space group P1¯; (no. 2), and was refined from single-crystal X-ray diffractometer data: a = 538.3(1), b = 687.5(1), c = 802.3(1) pm, α = 72.4(1)°, β = 85.7(1)°, γ = 68.1(1)°, wR2 = 0.0323, GooF = 1.048, 3157 F2 values, and 106 variables. The main motifs of the crystal structure are pairs of edge-linked [WO6]6− octahedra and fourfold oxygen-coordinated Te4+ atoms. The oxidation state of W6+ and Te4+ was further verified by measuring the characteristic binding energy values for the W 4f and the Te 3d core levels via X-ray photoelectron spectroscopy (XPS). In addition, DFT calculations of the structure, the associated electron localisation functions (ELF) and vibrational spectra have been carried out. The theoretical data clearly demonstrates the impact of the residual electron density located at the Te4+ ions, which can be directly interpreted as the presence of lone electron pairs within the solid structure. [ABSTRACT FROM AUTHOR]

We report on the synthesis of a new praseodymium molybdenum borate under high‐pressure/high‐temperature conditions. The new compound with the sum formula Pr3Mo4B6O24(OH)3 crystallizes acentrically in the monoclinic space group Cm displaying a new structure type. The structure was solved via single‐crystal structure determination. Additionally, the proposed structural model was confirmed by powder X‐ray diffraction, second harmonic generation measurement, and single‐crystal infrared and Raman spectroscopic investigation. [ABSTRACT FROM AUTHOR]

The compound Li3SiNO2:Eu2+ was synthesized in high temperature solid-state reactions in weld shut tantalum ampules and the crystal structure of Li3SiNO2 has been determined by single-crystal X-ray diffraction. It crystallizes in the monoclinic space group C2/c (no. 15) with the lattice parameters a = 1049.01(3), b = 1103.42(3), c = 511.86(2) pm, β = 116.14(1)°, and a volume of V = 0.53187(2) nm3. This compound is built up from two different layers, which are arranged alternately along the crystallographic a-axis. The results from single-crystal diffraction were confirmed by the Rietveld analysis of bulk samples. Moreover, Li3SiNO2 could be successfully doped with the activator ion Eu2+ and the luminescence spectroscopy of single-crystals revealed broad band emission at λmax = 601 nm (fwhm = 90 nm). [ABSTRACT FROM AUTHOR]

Monoclinic TeB4O8 was obtained in a Walker‐type multianvil apparatus at 10 GPa and 1273 K from TeO2 and B2O3. It crystallizes isotypically to the compounds AnB4O8 (An=Th, U) in the space group C2/c (Z=4) with the lattice parameters a=15.6978(8) Å, b=4.2284(2) Å, c=7.4305(4) Å, β=114.78(1)°, and V=447.80(4) Å3. Further, it has been characterized via X‐ray diffraction experiments and IR spectroscopy. [ABSTRACT FROM AUTHOR]

Monoclinic TeB4O8 was obtained in a Walker‐type multianvil apparatus at 10 GPa and 1273 K from TeO2 and B2O3. It crystallizes isotypically to the compounds AnB4O8 (An=Th, U) in the space group C2/c (Z=4) with the lattice parameters a=15.6978(8) Å, b=4.2284(2) Å, c=7.4305(4) Å, β=114.78(1)°, and V=447.80(4) Å3. Further, it has been characterized via X‐ray diffraction experiments and IR spectroscopy. [ABSTRACT FROM AUTHOR]