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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]

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]

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]

In an article published in Advanced Functional Materials, Markus Suta, Hubert Huppertz, and their colleagues introduce a new oxonitridoborate compound called AlB4O6N:Cr3+. This compound exhibits a highly efficient red line emission and has the potential to serve as an alternative luminescent pressure sensor. The researchers suggest that AlB4O6N:Cr3+ could offer more precise pressure calibration in diamond anvil cells compared to the current standard, ruby. The authors express gratitude to Abraham Siedler and Marie-Theres Wildauer for their contributions to the design of the inside back cover. [Extracted from the article]

At ambient conditions, PdSe2 dichalcogenides crystallize in the layered PdS2-type structure. If pressure is applied, the coordination number of palladium atoms increases and the three-dimensional pyrite-type structure with octahedral (PdSe6)4− coordination geometry is observed. For the first time, single crystals of a pyrite-type PdSe2 modification could be obtained and characterized, which were grown by multianvil high-pressure/high-temperature synthesis at 7.5 GPa and 1023 K. The crystals show the expected pyrite-type space group Pa3̅ (no. 205) and refinement results of a=613.26(3) pm, R1=0.0233, and wR2=0.0247 (all data) were received for HP-Pd0.84(1)Se2. The single-crystal data revealed significant defect formation on the palladium site with 16% vacancies, which is in line with the orthorhombic PdX2-type high-pressure polymorphs HP-Pd0.94(1)S2 and HP-Pd0.88(1)Se2. The tendency of vacancy formation on the palladium site could also be verified by EDX measurements. [ABSTRACT FROM AUTHOR]

The monoclinic lithium platinum selenide Li2Pt3Se4 was obtained via a multianvil high-pressure/high-temperature route at 8 GPa and 1200°C starting from a stoichiometric mixture of lithium nitride, selenium, and platinum. The structure of the ternary alkali metal-transition metal-selenide was refined from single-crystal X-ray diffractometer data: P21/ c (no. 14), a=525.9(2), b=1040.6(2), c=636.5(2) pm, β=111.91(1)°, R1=0.0269, wR2=0.0569 (all data) for Li2Pt3Se4. Furthermore, the isostructural mineral phases jaguéite (Cu2Pd3Se4) and chrisstanleyite (Ag2Pd3Se4) were reinvestigated in their ideal stoichiometric ratio. The syntheses of the mineral phases were also carried out under multianvil conditions. Single-crystal data revealed a hitherto not described structural disorder of the transition metal atoms. [ABSTRACT FROM AUTHOR]

The new lithium transition-metal sulfides Li 2 M 3 S 4 ( M =Pd, Pt) were obtained via multianvil high-pressure/high-temperature syntheses at 8 GPa and 1150 °C starting from a stoichiometric mixture of lithium nitride, sulfur, and palladium or platinum. Single crystal structure analyses indicated the space group P 2 1 / c (no. 14) with the following lattice parameters and refinement results: a =492.9(1), b =1005.9(2), c =614.9(2) pm, β =110.9 (1)°, R 1=0.0165, wR 2=0.0308 (all data) for Li 2 Pd 3 S 4 and a =498.2(1), b =1005.5(2), c =613.0(2) pm, β =110.8(1)°, R 1=0.0215, wR 2=0.0450 (all data) for Li 2 Pt 3 S 4 . The crystal structures are built up from two distinct Pd/Pt sites, one of which is a special position (0,0,0), two sulfur sites, and one lithium site. The atoms Pd2/Pt2 form isolated square planar PdS 4 /PtS 4 units, whereas the Pd1/Pt1 atoms form pairs of square planar PdS 4 /PtS 4 units, which are connected via a common edge. These two structural motives built up a three-dimensional network structure by linking through common corners. The lithium atoms are positioned inside of the so formed channels. Li 2 M 3 S 4 ( M =Pd, Pt) are isostructural to the minerals jaguéite, Cu 2 Pd 3 Se 4 and chrisstanleyite, Ag 2 Pd 3 Se 4 , which are up to now the only representatives of this structure type. Both compounds were studied with respect to their magnetic properties and can be classified as Pauli paramagnetic or diamagnetic. Regarding the possibility of lithium mobility inside the channels, of the structure, solid state 7 Li NMR and high-temperature single crystal investigations revealed localization of the lithium atoms on their crystallographic sites. [ABSTRACT FROM AUTHOR]

The new cerium polyborate Ce2B8O15 was synthesized under high-pressure/high-temperature conditions of 6 GPa and 1050 ºC in a Walker-type multianvil apparatus. The single-crystal structure determination revealed that the new compound crystallizes in the space group P2/c with the lattice parameters a = 916.6(2), b = 421.0(1), c = 1248.9(3) pm, β = 116.7(1)º, V = 0.4303(2) nm3, R1 = 0.0356, and wR2 = 0.0504. The crystal structure of Ce2B8O15 exhibits a new fundamental building block (FBB) in borate chemistry that consists of four BO4 tetrahedra and can be written as 4□: [Φ] 〈3□〉|□|. These FBB are interconnected via common corners, forming a complex threedimensional network that contains the Ce3+ cations. Ce2B8O15 represents the most boron rich rare-earth borate synthesized under high-pressure/high-temperature conditions so far. We report about the synthetic conditions, structural details, thermal behaviour, and the IR/Raman spectra of Ce2B8O15. [ABSTRACT FROM AUTHOR]

Abstract: High-pressure chemistry led to the synthesis of the rare-earth borate Pr4B10O21 using a Walker-type multianvil apparatus at 3.5GPa and 1050°C. The tetra-praseodymium(III)-decaborate crystallizes monoclinicly with four formula units in the space group P21/n and lattice parameters of a=710.2(2), b=1948.8(4), c=951.6(2)pm, and β=93.27(3)°. The boron–oxygen network consists of [BO4]5− tetrahedra and [BO3]3− groups; however, the [BO4]5− groups represent the major part (80%) due to the high-pressure conditions during the synthesis. The praseodymium ions are coordinated by 10 and 12 oxygen atoms. Along with a detailed description of the crystal structure, temperature programmed X-ray powder diffraction data are shown, demonstrating the metastable character of this compound. [Copyright &y& Elsevier]

Abstract: The hexagonal high-pressure (HP) modification of NdPtSn was prepared under multianvil high-pressure (10.5 GPa) high-temperature (1425 K) conditions from the orthorhombic normal-pressure (NP) modification. NP- and HP-NdPtSn were studied by X-ray powder and single crystal diffraction: TiNiSi type, Pnma, , , , , 441 values, 20 variable parameters for NP-NdPtSn, and ZrNiAl type, , , , , 248 values, 14 variable parameters for HP-NdPtSn. Temperature dependent susceptibility measurements reveal paramagnetism for HP-NdPtSn above 20 K with an experimental magnetic moment of 3.73(2) Nd mol and a paramagnetic Curie temperature of K. The low-temperature data indicate spin glass behavior with a freezing temperature around 4.5 K. The spin glass anomalies are also evident from specific heat measurements. [Copyright &y& Elsevier]

Abstract: The δ modification of lanthanum meta-oxoborate was discovered during our systematic investigations in the field of oxoborates, synthesized under high-pressure conditions. δ-La(BO2)3 (≡δ-LaB3O6) was obtained at high-pressure (5.5 GPa) and high-temperature (1050 °C) in a Walker-type multianvil apparatus. The monoclinic compound crystallizes with four formula units in the space group , exhibiting lattice parameters of , , , and . Due to the synthesis under high-pressure conditions, the structure exhibits [BO4]5− tetrahedra exclusively, which are connected via common corners. Additionally, 1/6 of the oxygen atoms are bridging three boron atoms (O[3]), leading to a network structure with ten-membered rings of [BO4]5− tetrahedra (), in which the La3+ ions are coordinated by twelve oxygen atoms (). After a discussion of the structure, infrared and temperature-dependent X-ray powder diffraction data are presented. [Copyright &y& Elsevier]

Abstract: The new monoclinic cerium borogermanate Ce6(BO4)2Ge9O22 was synthesized under high-pressure and high-temperature conditions in a Walker-type multianvil apparatus at 10.5GPa and 1200°C. Ce6(BO4)2Ge9O22 crystallizes with two formula units in the space group P21/n with lattice parameters , , pm, and . As the parameter pressure favours the formation of compounds with cations possessing high coordination numbers, it was possible to produce simultaneously BO4-tetrahedra and GeO6-octahedra in one and the same borogermanate for the first time. Furthermore, the cerium atoms show high coordination numbers (C.N.: 9 and 11), and one oxygen site bridges one boron and two germanium atoms (O[3]), which is observed here for the first time. Besides a structural discussion, temperature-dependent X-ray powder diffraction data are presented, demonstrating the metastable character of this high-pressure phase. [Copyright &y& Elsevier]

In this work we report about a new oxoborate β-ZnB4O7 synthesized under high-pressure/high-temperature conditions from zinc oxide ZnO and boron oxide B2O3 with a walker-type multianvil apparatus at 10.5 GPa and 1100 °C. Single crystal X-ray structure determination of β-ZnB4O7 revealed: Cmcm, a=1085.0(1) pm, b=648.9(1) pm, c=517.3(1) pm, Z=4, R1=0.0182, wR2=0.0478 (all data). The compound exhibits a new structure type which is built up from linked tetrahedral BO4-groups (□) forming a network. The most prominent feature of the tetrahedral network is that there is an oxygen, which is coordinated to three borons. The network exhibits channels formed from four- and six-membered rings running along [001]. The Zn2+-cations are positioned in the large six-ring channels, whereas the channels built up by four membered rings remain empty. According to the conception of fundamental building blocks β-ZnB4O7 can be classified with the notation 8□:〈3□〉=〈6□〉=〈3□〉. The relation of the crystal structure of the high-pressure phase β-ZnB4O7 to the normal-pressure phase α-ZnB4O7 is discussed. Furthermore we report about temperature-resolved in situ powder diffraction measurements and IR-spectroscopic investigations on β-ZnB4O7. [Copyright &y& Elsevier]

The first high-pressure scandium tellurate HP-Sc2TeO6 was synthesized from an NP-Sc2TeO6 normal-pressure precursor at 12 GPa and 1173 K using a multianvil apparatus (1000 t press, Walker-type module). The compound crystallizes in the monoclinic space group P2/c (no. 13) with a = 729.43(3), b = 512.52(2), c = 1095.02(4) pm and β = 103.88(1)°. The structure was refined from X-ray single-crystal diffractometer data: R1 = 0.0261, wR2 = 0.0344, 568 F2 values and 84 variables. HP-Sc2TeO6 is isostructural to Yb2WO6 and is built up from TeO6 octahedra, typical for tellurate(VI) compounds. During synthesis, a reconstructive transition from P321 (normal-pressure modification) to P2/c (high-pressure modification) takes place and the scandium–oxygen distances as well as the coordination number of scandium increase. However, the coordination sphere around the Te6+ cations gets only slightly distorted. High-temperature powder XRD investigations revealed a back-transformation of HP-Sc2TeO6 to the ambient-pressure modification above 973 K. [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]

Monoclinic Tb 3 B 12 O 19 (OH) 7 was obtained by multianvil high-pressure/high-temperature syntheses at 6 GPa and 650 °C. The crystal structure was investigated by single-crystal X-ray diffraction methods and space group C 2 (no. 5) with the unit cell parameters a = 24.2299(5) Å, b = 4.4667(1) Å, c = 7.0964(2) Å, β = 94.58(1)°, and two formula units per cell were revealed. Powder X-ray diffraction, infrared spectroscopy and the investigation of its second harmonic generation properties support the proposed structural model. The terbium hydroxyborate borate Tb 3 B 12 O 19 (OH) 7 was synthesized under high-pressure conditions in a Walker-type multianvil device at 6 GPa and 650 °C. The new compound was found to crystzallize monoclinically in the space group C 2 (no. 5) with the unit cell parameters a = 24.2299(5) Å, b = 4.4667(1) Å, c = 7.0964(2) Å, β = 94.58(1) °, and two formula units per cell by single-crystal diffraction methods. Tb 3 B 12 O 19 (OH) 7 was further characterized using powder X-ray diffraction, infrared spectroscopy and the investigation of its second harmonic generation properties. [Display omitted] • Tb 3 B 12 O 19 (OH) 7 was synthesized at 6 GPa and 650 °C in a Walker-type multianvil device. • Its crystal structure is built up by a repetitive [B 6 O 13 ]8- building block. • The new compound displays a non-centrosymmetric crystal structure and a strong second harmonic generation effect. [ABSTRACT FROM AUTHOR]

The new mixed valent iron borate Fe8B15O28(OH)8 was synthesized under high-pressure/high-temperature conditions of 12 GPa and 850 °C in a multianvil device (Walker-type module). It crystallizes with four formula units in the tetragonal space group I41/a with the structural parameters a = 1142.3(2) and c = 1537.4(2) pm (V = 2.006(1) nm3, R 1 = 0.0586, wR 2 = 0.0721 (all data)). Fe8B15O28(OH)8 is composed exclusively from corner-sharing BO4 tetrahedra and can be described as two identical interpenetrating three-dimensional networks that are built up from B11O28 building blocks and interconnecting BO2O(OH) units. The FeII and FeIII ions in FeII 5FeIII 3B15O28(OH)8 are located in the interspaces between the two networks. 57Fe Mössbauer, Raman, and infrared spectroscopic data are reported. [ABSTRACT FROM AUTHOR]