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1. Coexistence of Long-Range Magnetic Order and Magnetic Frustration of a Novel Two-Dimensional S = 1/2 Structure: Na2Cu3(SeO3)4

   https://doi.org/10.3390/magnetism4010003  

   Williams, Emily D; Taddei, Keith M; Ranmohotti, Kulugammana_G S; Narayanan, Narendirakumar; Heitmann, Thomas; Kolis, Joseph W; Sanjeewa, Liurukara D (March 2024, Magnetism)

   Novel quantum materials offer the opportunity to expand next-generation computers, high-precision sensors, and new energy technologies. Among the most important factors influencing the development of quantum materials research is the ability of inorganic and materials chemists to grow high-quality single crystals. Here, the synthesis, structure characterization and magnetic properties of Na2Cu3(SeO3)4 are reported. It exhibits a novel two-dimensional (2D) structure with isolated layers of Cu nets. Single crystals of Na2Cu3(SeO3)4 were grown using a low-temperature hydrothermal method. Single-crystal X-ray diffraction reveals that Na2Cu3(SeO3)4 crystallizes in the monoclinic crystal system and has space group symmetry of P21/n (No.14) with a unit cell of a = 8.1704(4) Å, b = 5.1659(2) Å, c = 14.7406(6) Å, β = 100.86(2), V = 611.01(5) Å3 and Z = 2. Na2Cu3(SeO3)4 comprises a 2D Cu-O-Cu lattice containing two unique copper sites, a CuO6 octahedra and a CuO5 square pyramid. The SeO3 groups bridge the 2D Cu-O-Cu layers isolating the neighboring Cu-O-Cu layers, thereby enhancing their 2D nature. Magnetic properties were determined by measuring the magnetic susceptibility of an array of randomly oriented single crystals of Na2Cu3(SeO3)4. The temperature-dependent magnetic measurement shows an antiferromagnetic transition at TN = 4 K. These results suggest the fruitfulness of hydrothermal synthesis in achieving novel quantum materials and encourage future work on the chemistry of transition metal selenite. 

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2. Synthesis, Crystal and Electronic Structure of Ca ₄ CdIn ₂ Ge ₄ : A Quaternary Variant of the Monoclinic Mg ₅ Si ₆ Structure

   https://doi.org/10.1002/zaac.202500006  

   Ghosh, Kowsik; Bobev, Svilen (May 2025, Zeitschrift für anorganische und allgemeine Chemie)

   Reported is the synthesis of a new polar intermetallic phase, Ca₄CdIn₂Ge₄, crystals of which can be readily obtained employing the In‐flux method. The structure and the chemical composition of the new compound are established based on single‐crystal X‐Ray diffraction and energy‐dispersive X‐Ray spectroscopy data. Ca₄CdIn₂Ge₄crystallizes in a monoclinic crystal system with the space groupC2/m(no. 12) with lattice parametersa = 16.7383(12) Å,b = 4.4235(3) Å,c = 7.4322(5) Å, andβ = 106.560(1)°. The structure can formally be classified as a variant of the Mg₅Si₆structure type (Pearson symbolmS22). Considering the InGe and CdGe interactions as mostly covalent, the polyanionic substructure can be rationalized as consisting of ribbons of edge‐shared [InGe₄] tetrahedra connected by Ge₂dimers and bridged by Cd atoms in nearly square‐planar environment. Chemical bonding analysis based on TB‐LMTO‐ASA calculations affirms the notion for covalent character of the GeGe bonding with the dimers. The calculations also show that the bonding in the tetrahedra is more covalent in character than the bonding in square‐planar fragments, with the CaGe interactions being the least covalent among all interactions, though not exactly ionic. 

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3. Synthesis, Structure, and Properties of the Complex Zintl Phase Eu9Zn4.5As9: A Candidate Topological Insulator and Thermoelectric Material

   https://doi.org/10.3390/cryst16020137  

   Watts, Spencer R; Pokhvata, Olha; Kandabadage, Thimira; Thipe, Bhushan; Bai, Xiaojian; Bobev, Svilen; Baranets, Sviatoslav (February 2026, Crystals)

   Reported are the synthesis and detailed analysis of the crystal and electronic structure of the novel Zintl phase Eu9Zn4.5As9. This material was identified in the densely populated Eu–Zn–As compositional space. For structure determination and for property measurements, suitable single crystals of this compound were grown from either Sn- or Pb-flux. Single-crystal X-ray diffraction methods indicate that Eu9Zn4.5As9 crystallizes in the orthorhombic crystal system with the space group Pnma (a = 12.1953(7) Å, b = 4.3730(2) Å, c = 42.674(2) Å) and is formally isostructural to Ca9Mn4+xSb9, the less common “9–4–9” type. The structure is heavily disordered, with multiple partially occupied sites, yet, according to the Zintl-Klemm formalism, a charge-balanced composition (Eu2+)9(Zn2+)4.5(As3−)9 is attained. Electronic structure calculations for a model, disorder-free structure indicate no energy gap between the valence and the conduction bands and suggest (semi)metallic behavior. Preliminary susceptibility measurements confirm the expected divalent nature of Eu2+ ([Xe] 4f7 ground state). 

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4. Identification of the structure of the Bi promoted Pt non-oxidative coupling of methane catalyst: a nanoscale Pt ₃ Bi intermetallic alloy

   https://doi.org/10.1039/C8CY02171F  

   Zhu Chen, Johnny; Wu, Zhenwei; Zhang, Xiaoben; Choi, Slgi; Xiao, Yang; Varma, Arvind; Liu, Wei; Zhang, Guanghui; Miller, Jeffrey T. (March 2019, Catalysis Science & Technology)

   Recently, stable non-oxidative conversion of methane (NOCM) for up to 8 h with a C 2 selectivity greater than 90% has been reported over Pt–Bi/ZSM-5 at moderate temperatures (600–700 °C). In this study, we show that the structure of the bimetallic nanoparticles on Pt–Bi/ZSM-5 catalyst is similar to Pt–Bi/SiO 2 . EXAFS indicates the formation of Pt-rich bimetallic Pt–Bi nanoparticles with Pt–Bi bond distance of 2.80 Å. The XRD spectra (on SiO 2 ) are consistent with cubic, intermetallic surface Pt 3 Bi phase on a Pt core. The Pt 3 Bi structure is not known in the thermodynamic phase diagram. In all catalysts, only a small fraction of Bi alloys with Pt. At high Bi loadings, excess Bi reduces at high temperature, covering the catalytic surface leading to a loss in activity. At lower Bi loadings with little excess Bi, the Pt 3 Bi surface is effective for non-oxidative coupling of CH 4 (on ZSM-5) and propane dehydrogenation (on SiO 2 ). 

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5. Crystal structure of 1-[(4-methylbenzene)sulfonyl]pyrrolidine

   https://doi.org/10.1107/S205698902000208X  

   Stenfors, Brock A.; Staples, Richard J.; Biros, Shannon M.; Ngassa, Felix N. (March 2020, Acta Crystallographica Section E Crystallographic Communications)

   The molecular structure of the title compound, C 11 H 15 NO 2 S, features a sulfonamide group with S=O bond lengths of 1.4357 (16) and 1.4349 (16) Å, an S—N bond length of 1.625 (2) Å, and an S—C bond length of 1.770 (2) Å. When viewing the molecule down the S—N bond, both N—C bonds of the pyrrolidine ring are oriented gauche to the S—C bond with torsion angles of −65.6 (2)° and 76.2 (2)°. The crystal structure features both intra- and intermolecular C—H...O hydrogen bonds, as well as intermolecular C—H...π and π–π interactions, leading to the formation of sheets parallel to the ac plane. 

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