Crystal Structures, Dimorphism and Lithium Mobility of Li₇MO₆ (M = Bi, Ru, Os)

Abstract

Li7MO6 (M = Bi, Ru, Os) have been synthesized by solid state reaction of Li2O with Bi2O3, or MO2 (M = Ru, Os) and characterized using powder X‐ray diffraction, differential scanning calorimetry, magnetic susceptibility (for M = Ru, Os), ionic conductivity and 6Li solid state NMR (for M = Bi) measurements. All three compounds exhibit a temperature induced triclinic – rhombohedral phase transition. Structures of the new low temperature triclinic phases have been refined by the Rietveld method from powder X‐ray data using atomic parameters of Li7TaO6 as a starting model (Li7BiO6: triclinic, $P{\bar 1}$, a = 5.5071(1), b = 6.0425(1), c = 5.5231(1) Å, α = 116.912(1), β = 120.867(1), γ = 62.234(1)°, V = 133.96(1) Å3, Z = 1, T = 230 K; Li7RuO6: triclinic, $P{\bar 1}$, a = 5.3654(1), b = 5.8584(1), c = 5.3496(1) Å, α = 117.182(1), β = 119.117(1), γ = 62.632(1)°, V = 124.43(1) Å3, Z = 1, T = 295 K; Li7OsO6: triclinic, $P{\bar 1}$, a = 5.3786(1), b = 5.8725(1), c = 5.3591(1) Å, α = 117.193(1), β = 119.277(1), γ = 62.700(1)°, V = 125.15(1) Å3, Z = 1, T = 295 K). Upon cooling, Li7RuO6 and Li7OsO6 undergo a magnetic transition at 12 and 13 K, respectively, from the paramagnetic to the antiferromagnetic state. The higher ionic conductivity of Li7BiO6 at T < 300 °C, as compared to Li7RuO6 and Li7OsO6, can be ascribed to the undergoing of the triclinic – rhombohedral transition at a much lower temperature. At T > 300 °C, the ionic conductivity of all three compounds increases sharply due to the melting of the lithium sublattice; for Li7RuO6 and Li7OsO6 the latter effect is superimposed by the phase transitions to the rhombohedral modifications.

Lewis Acidic Behavior of MoOF4 towards the Alkali Metal Fluorides in Anhydrous Hydrogen Fluoride Solutions

“…The coordination tetrahedron around Li (2) shares an edge with the coordination tetrahedron generated by the crystallographic inversion center ( Figure S2b). Similar edge-sharing tetrahedra containing disordered Li + cations have been described previously in compounds such as Li 3 InF 6 , [24] Li 7 OsO 6 , [25] and Li 9 B 19 S 33 . [26] Moreover, the coordination of the [Mo 2 O 2 F 9 ]anions to the lithium cations form two-dimensional infinite sheets, which are oriented parallel to the (011) plane, see Figure S3 (for a topological comparison of the crystal structures, see below).…”

From Micro to Macro: Access to Long‐Range Li+ Diffusion Parameters in Solids via Microscopic 6, 7Li Spin‐Alignment Echo NMR Spectroscopy

“…Li 7 BiO 6 is built of triple slabs of composition [Li 2 BiO 6 ] with Li occupying the octahedral voids of two close-packed oxygen layers. [132,133] These slabs are stacked in such a way that an approximate hexagonal close packing of oxygen atoms results. Within the gap between adjacent slabs, lithium is located in tetrahedral voids.…”

Synthesis and Crystal Structure of the Partially Oxidized Cyanoplatinates Rb1.75[Pt(CN)4]·1.25H2O and Cs1.75[Pt(CN)4]·0.5H2O

“…However, structural studies of these systems are desirable for understanding further details and for checking the applicability of the one‐dimensional band theory 11. We already reported on anhydrous K 2 [Pt(CN) 4 ],12 Rb 2 [Pt(CN) 4 ],13 the halides A 2 [Pt(CN) 4 ] X 2 ( A = alkali metal, X = halogen),14,15 and the hydrogen peroxide adducts A 2 [Pt(CN) 4 ] · H 2 O 2 16. In order to clarify and to complete the investigations on platinum cyanoplatinates, we investigated again this class of compounds, and we succeeded to synthesize suitable single crystals of partially oxidized Rb 1.75 [Pt(CN) 4 ] · 1.25H 2 O, and Cs 1.75 [Pt(CN) 4 ] · 0.5H 2 O with lower amounts of hydrated water then previously reported, and have characterized them by X‐ray single crystal diffraction, differential thermal analysis (DTA), thermogravimetry (TG), infrared (IR), and Raman spectroscopy.…”