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1. Experimental and computational investigations of TiIrB: a new ternary boride with Ti _1+x Rh _2−x+y Ir _3−y B ₃ -type structure

   https://doi.org/10.1515/znb-2021-0121  

   Scheifers, Jan P.; Gibson, Kate A.; Fokwa, Boniface P. (October 2021, Zeitschrift für Naturforschung B)

   Abstract A new ternary phase, TiIrB, was synthesized by arc-melting of the elements and characterized by powder X-ray diffraction. The compound crystallizes in the orthorhombic Ti 1+ x Rh 2− x + y Ir 3− y B 3 structure type, space group Pbam (no. 55) with the lattice parameters a  = 8.655(2), b  = 15.020(2), and c  = 3.2271(4) Å. Density Functional Theory (DFT) calculations were carried out to understand the electronic structure, including a Bader charge analysis. The charge distribution of TiIrB in the Ti 1+ x Rh 2− x + y Ir 3− y B 3 -type phase has been evaluated for the first time, and the results indicate that more electron density is transferred to the boron atoms in the zigzag B 4 units than to isolated boron atoms. 

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2. Synthesis, chiral crystal structure, and magnetic properties of Ba ₃ Ga ₂ O ₅ Cl ₂

   https://doi.org/10.1107/S2052520622004723  

   Rine, Jeremy; Yang, Yongqi; Shu, Zhixue; Zhao, Jianda; Xie, Weiwei; Kong, Tai (August 2022, Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials)

   A new compound, Ba 3 Ga 2 O 5 Cl 2 , isostructural with Ba 3 Fe 2 O 5 Cl 2 , was synthesized by solid-state reaction in air. Through single-crystal and powder X-ray diffraction analysis, the crystal structure was determined to be cubic with chiral space group I 2 1 3 and unit-cell parameter a  = 9.928 (1) Å. The Ga 3+ ions in Ba 3 Ga 2 O 5 Cl 2 are coordinated by O atoms and form GaO 4 tetrahedra. Ten neighboring GaO 4 tetrahedra are further bridged through corner sharing and rotation along the body diagonal, producing the chiral structure. Magnetization measurements indicate temperature-independent diamagnetic behavior, which is qualitatively consistent with core diamagnetism from all the constituent elements. 

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3. Crystal structure and synchrotron X-ray powder reference pattern for the porous pillared cyanonickelate, Ni(3-amino-4,4′-bipyridine)[Ni(CN) ₄ ]

   https://doi.org/10.1017/S0885715624000058  

   Wong-Ng, W; Culp, J; Kaduk, JA; Chen, YS; Lapidus, S (March 2024, Powder Diffraction)

   The structure of Ni(3-amino-4,4′-bipyridine)[Ni(CN)₄] (or known as Ni-BpyNH₂) in powder form was determined using synchrotron X-ray diffraction and refined using the Rietveld refinement technique (R= 8.8%). The orthorhombic (Cmca) cell parameters were determined to bea= 14.7218(3) Å,b= 22.6615(3) Å,c= 12.3833(3) Å,V= 4131.29(9) ų, andZ= 8. Ni-BpyNH₂forms a 3-D network, with a 2-D Ni(CN)₄net connecting to each other via the BpyNH₂ligands. There are two independent Ni sites on the net. The 2-D nets are connected to each other via the bonding of the pyridine “N” atom to Ni2. The Ni2 site is of six-fold coordination to N with relatively long Ni2–N distances (average of 2.118 Å) as compared to the four-fold coordinated Ni1–C distances (average of 1.850 Å). The Ni(CN)₄net is arranged in a wave-like fashion. The functional group, –NH₂, is disordered and was found to be in them-position relative to the N atom of the pyridine ring. Instead of having a unique position, N has ¼ site occupancy in each of the fourm-positions. The powder reference diffraction pattern for Ni-BpyNH₂was prepared and submitted to the Powder Diffraction File (PDF) at the International Centre of Diffraction Data (ICDD). 

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4. Spin Transitions and Compressibility of ε‐Fe ₇ N ₃ and γ′‐Fe ₄ N: Implications for Iron Alloys in Terrestrial Planet Cores

   https://doi.org/10.1029/2020JB020660  

   Lv, Mingda; Liu, Jiachao; Zhu, Feng; Li, Jie; Zhang, Dongzhou; Xiao, Yuming; Dorfman, Susannah M. (November 2020, Journal of Geophysical Research: Solid Earth)

   Abstract Iron nitrides are possible constituents of the cores of Earth and other terrestrial planets. Pressure‐induced magnetic changes in iron nitrides and effects on compressibility remain poorly understood. Here we report synchrotron X‐ray emission spectroscopy (XES) and X‐ray diffraction (XRD) results for ε‐Fe₇N₃and γ′‐Fe₄N up to 60 GPa at 300 K. The XES spectra reveal completion of high‐ to low‐spin transition in ε‐Fe₇N₃and γ′‐Fe₄N at 43 and 34 GPa, respectively. The completion of the spin transition induces stiffening in bulk modulus of ε‐Fe₇N₃by 22% at ~40 GPa, but has no resolvable effect on the compression behavior of γ′‐Fe₄N. Fitting pressure‐volume data to the Birch‐Murnaghan equation of state yieldsV₀ = 83.29 ± 0.03 (ų),K₀ = 232 ± 9 GPa,K₀′ = 4.1 ± 0.5 for nonmagnetic ε‐Fe₇N₃above the spin transition completion pressure, andV₀ = 54.82 ± 0.02 (ų),K₀ = 152 ± 2 GPa,K₀′ = 4.0 ± 0.1 for γ′‐Fe₄N over the studied pressure range. By reexamining evidence for spin transition and effects on compressibility of other candidate components of terrestrial planet cores, Fe₃S, Fe₃P, Fe₇C₃, and Fe₃C based on previous XES and XRD measurements, we located the completion of high‐ to low‐spin transition at ~67, 38, 50, and 30 GPa at 300 K, respectively. The completion of spin transitions of Fe₃S, Fe₃P, and Fe₃C induces elastic stiffening, whereas that of Fe₇C₃induces elastic softening. Changes in compressibility at completion of spin transitions in iron‐light element alloys may influence the properties of Earth's and planetary cores. 

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5. Ca ₂ Ga ₄ Ge ₆ and Ca ₃ Ga ₄ Ge ₆ : Synthesis, Structure, and Electronic Properties

   https://doi.org/10.1002/zaac.202100342  

   Hodge, Kelsey L; Davis, H Olivia; Koster, Karl G; Windl, Wolfgang; Moore, Curtis E; Goldberger, Joshua E (August 2022, Zeitschrift für anorganische und allgemeine Chemie)

   Abstract During the search for transition metal‐free alkyne hydrogenation catalysts, two new ternary Ca−Ga−Ge phases, Ca₂Ga₄Ge₆(Cmc2₁, a=4.1600(10) Å, b=23.283(5) Å, c=10.789(3) Å) and Ca₃Ga₄Ge₆(C2/m, a=24.063(2) Å, b=4.1987(4) Å, c=10.9794(9) Å, β=91.409(4)°), were discovered. These compounds are isostructural to the previously established Yb₂Ga₄Ge₆and Yb₃Ga₄Ge₆analogues, and according to Zintl‐Klemm counting rules, consist of anionic [Ga₄Ge₆]⁴⁻and [Ga₄Ge₆]⁶⁻frameworks in which every Ga and Ge atom would have a formal octet with no Ga−Ga or Ga−Ge π‐bonding. These compounds are metallic, based on temperature dependent electrical resistivity and thermopower measurements for Ca₃Ga₄Ge₆, along with density functional theory calculations for both phases. Unlike the highly active 13‐layer trigonal CaGaGe phase, these new compounds exhibit minimal activity in the semi/full alkyne hydrogenation of phenylacetylene, which is consistent with previous observations that the lack of a formal octet for framework atoms is essential for catalysis in these Zintl‐Klemm compounds. 

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