Crystal structure of lithium vanadium fluoride (LiV2F6), a mixed-valence trirutile

Abstract

LiV2F6 crystallizes in space group P42/mnm with lattice constants a = 4.697 (3) A, c = 9.289 (3) A, and Z = 2. The structure refinement for a trirutile lattice [V at 4e, z / c = 0.33263 (8); F1 at 4f, x / a = 0.3094 (11); F2 at Sj, x / a = 0.2971 (9), z / c = 0.3277 (3)] gave R = 5.0% for 371 reflections and showed two edge-sharing distorted VF, octahedra and a single V site. The compound is truly mixed-valent. The distortions of the VF6 octahedra and the inferred reordering of VI1 and VI1' energy levels help to explain the temperature-dependent magnetic susceptibility of LiV2F6 (which has been remeasured). Madelung energies are also reported.

Weyl Monoloop Semi-Half-Metal and Tunable Anomalous Hall Effect

“…Remarkably, the optimized lattice parameters of LiV 2 F 6 are in excellent agreement with the experimental result. 44 Before proceeding, identifying the magnetic ground state of LiV 2 F 6 impels us to pursue the fascinating properties. To check the magnetic ground state of LiV 2 F 6 , we consider four different kinds of possible magnetic orders, including ferromagnetic (FM) and three antiferromagnetic (AFM) orders as displayed in Figure S1 (see Supporting Information).…”

“…The coexistence of fully spin-polarized and linear dispersion in the monoloop states can be realized in rutile-type metal fluorides LiV 2 F 6 . 44 Unlike most predicted magnetic nodal line semi-metals, the proposed LiV 2 F 6 meets all the screening criteria and has the characteristics of semi-metallic and flatness and is simple and clean, which vastly promotes the development of the SHM family. The band crossing of the spin-up channel forms a Weyl monoloop close to the Fermi level, which requires an out-of-plane magnetization and a preserved vertical mirror symmetry.…”

Charge Ordering of Multielectronic Clusters in Mixed‐Valence Molecular Crystals

“…When certain conditions are satisfied the ground state of the cluster with localized electrons df-d: (a, b metal ions, spins s, = 1, sb = 3/2) is the orbitally non-degenerate multiplet 6 , 4 , 2~ [5] split by the exchange and resonance interaction on states with different parity: 2Alg(2u), 4Alg(2u), 6Alg(zu). The energies of the stationary states are described by the following where J und p are the parameters of multielectronic Heisenberg-type exchange interaction and transfer, respectively [5].…”

“…In this paper the theory of charge ordering is generalized to the case of crystals consisting of multielectronic clusters of the type dZ-d3. The vanadium dimers V(I1)-V(II1) in trirutile are exemplified by such systems [6].…”

Preparation and Crystal Structure of a New Lithium Vanadium Fluoride Li2VF6 with Trirutile-type Structure

“…For lithium vanadium fluorides the following phases have been reported in literature: cryolite type-related orthorhombic α-and monoclinic β -Li 3 V (III) F 6 [7], LiV (II/III) 2 F 6 (tetragonal, a mixed-valence trirutile structure) [8], and LiV (V) F 6 (rhombohedral, LiSbF 6 type) [9]. In this contribution we report on the synthesis and the crystal structure of the new lithium vanadium fluoride Li 2 V (IV) F 6 .…”