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1. Crystal structure of [Ni(OH ₂ ) ₆ ]Cl ₂ ·(18-crown-6) ₂ ·2H ₂ O

   https://doi.org/10.1107/S2056989024010041  

   Brannon, Jacob P; Liang, Kevin; Stieber, S_Chantal E (November 2024, Acta Crystallographica Section E Crystallographic Communications)

   The crystal structure of the title compound, hexaaquanickel(II) dichloride–1,4,7,10,13,16-hexaoxacyclooctadecane–water (1/2/2), [Ni(H₂O)₆]Cl₂·2C₁₂H₂₄O₆·2H₂O, is reported. The asymmetric unit contains half of the Ni(OH₂)₆moiety with a formula of C₁₂H₃₂ClNi_0.50O₁₀at 105 K and triclinic (P1) symmetry. The [Ni(OH₂)₆]²⁺cation has close to ideal octahedral geometry with O—Ni—O bond angles that are within 3° of idealized values. The supramolecular structure includes hydrogen bonding between the water ligands, 18-crown-6 molecules, Cl⁻anions, and co-crystallized water solvent. Two crown ether molecules flank the [Ni(OH₂)₆]²⁺molecule at the axial positions in a sandwich-like structure. The relatively symmetric hydrogen-bonding network is enabled by small Cl⁻counter-ions and likely influences the more idealized octahedral geometry of [Ni(OH₂)₆]²⁺. 

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2. Electron and Spin Delocalization in [Co ₆ Se ₈ (PEt ₃ ) ₆ ] ^0/+1 Superatoms

   https://doi.org/10.1002/cphc.202300064  

   Xu, Yunyao; Chen, Jia; Aydt, Alexander P.; Zhang, Lichirui; Sergeyev, Ivan; Keeler, Eric G.; Choi, Bonnie; He, Shoushou; Reichman, David R.; Friesner, Richard A.; et al (January 2024, ChemPhysChem)

   ChemPhysChem (Ed.)

   Abstract Molecular clusters can function as nanoscale atoms/superatoms, assembling into superatomic solids, a new class of solid‐state materials with designable properties through modifications on superatoms. To explore possibilities on diversifying building blocks, here we thoroughly studied one representative superatom, Co₆Se₈(PEt₃)₆. We probed its structural, electronic, and magnetic properties and revealed its detailed electronic structure as valence electrons delocalize over inorganic [Co₆Se₈] core while ligands function as an insulated shell.⁵⁹Co SSNMR measurements on the core and³¹P,¹³C on the ligands show that the neutral Co₆Se₈(PEt₃)₆is diamagnetic and symmetric, with all ligands magnetically equivalent. Quantum computations cross‐validate NMR results and reveal degenerate delocalized HOMO orbitals, indicating aromaticity. Ligand substitution keeps the inorganic core nearly intact. After losing one electron, the unpaired electron in [Co₆Se₈(PEt₃)₆]⁺¹is delocalized, causing paramagnetism and a delocalized electron spin. Notably, this feature of electron/spin delocalization over a large cluster is attractive for special single‐electron devices. 

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3. ErMn ₆ Sn ₆ : A Promising Kagome Antiferromagnetic Candidate for Room‐Temperature Nernst Effect‐Based Thermoelectrics

   https://doi.org/10.1002/adfm.202418715  

   Emmanuel, Olajumoke Oluwatobiloba; Gupta, Shuvankar; Ke, Xianglin (September 2025, Advanced Functional Materials)

   Abstract The Nernst effect, the generation of a tranverse electric voltage in the presence of longitudinal thermal gradient, has garnered significant attention in the realm of magnetic topological materials due to its superior potential for thermoelectric applications. In this work, the electronic and thermoelectric transport properties of a Kagome magnet ErMn₆Sn₆are investigated, a compound showing an incommensurate antiferromagnetic phase followed by a ferrimagnetic phase transition upon cooling. It is shown that in the antiferromagnetic phase ErMn₆Sn₆exhibits both topological Nernst effect and anomalous Nernst effect, analogous to the electric Hall effects, with the Nernst coefficient reaching 1.71 µV K⁻¹ at 300 K and 3 T. This value surpasses that of most of previously reported state‐of‐the‐art canted antiferromagnetic materials and is comparable to recently reported other members of RMn₆Sn₆(R = rare‐earth, Y, Lu, Sc) compounds, which makes ErMn₆Sn₆a promising candidate for advancing the development of Nernst effect‐based thermoelectric devices. 

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4. 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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5. Comparative Thermal Insulation Nature of Ca ₂ FeMnO _6−δ and Sr ₂ FeMnO _6−δ

   https://doi.org/10.1149/2754-2734/ad27dc  

   Schultz, Ebony; Guinn, Mandy; Azure, Alexa D; Hona, Ram Krishna (February 2024, ECS Advances)

   unknown (Ed.)

   In this study, we investigate the utility of Ca₂FeMnO_6-δand Sr₂FeMnO_6-δas materials with low thermal conductivity, finding potential applications in thermoelectrics, electronics, solar devices, and gas turbines for land and aerospace use. These compounds, characterized as oxygen-deficient perovskites, feature distinct vacancy arrangements. Ca₂FeMnO_6-δadopts a brownmillerite-type orthorhombic structure with ordered vacancy arrangement, while Sr₂FeMnO_6-δadopts a perovskite cubic structure with disordered vacancy distribution. Notably, both compounds exhibit remarkably low thermal conductivity, measuring below 0.50 Wm⁻¹K⁻¹. This places them among the materials with the lowest thermal conductivity reported for perovskites. The observed low thermal conductivity is attributed to oxygen vacancies and phonon scattering. Interestingly as SEM images show the smaller grain size, our findings suggest that creating vacancies and lowering the grain size or increasing the grain boundaries play a crucial role in achieving such low thermal conductivity values. This characteristic enhances the potential of these materials for applications where efficient heat dissipation, safety, and equipment longevity are paramount. 

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