Mixed Valence Tungsten(IV,V) Compounds with Layered Structures (Part II)): Synthesis and Crystal Structures of Cu_1−x[W₂O₂Cl₆] and Cu_1−x[W₄O₄Cl₁₀]

Abstract

The reaction of CuCl with WOCl3 at 400 °C leads to a mixture of Cu1−x[W2O2Cl6] (1) and Cu1−x[W4O4Cl10] (2) in form of black lustrous needles. Both compounds crystallize in space group C2/m with a = 12.7832(5) Å, b = 3.7656(2) Å, c = 10.7362(3) Å, β = 119.169(2)° for 1 and a = 12.8367(19) Å, b = 3.7715(7) Å, c = 15.955(3) Å, β = 102.736(5)° for 2. The structures are made up of WO2Cl4 octahedra. In the case of 1 two octahedra are edge‐sharing via chlorine atoms to form pairs which are linked via the trans‐positioned oxygen atoms to form infinite double strands $^{\infty}_{1}\rm [W_{2}O_{4/2}Cl_{2/2}Cl_{4}]$. In the structure of 2 two of these double strands are condensed via terminal chlorine atoms to form quadruple strands $^{\infty}_{1}\rm [W_{4}O_{8/2}Cl_{6/2}Cl_{4}]$. Like for all members of the Mx[W2O2X6] structure family (X = Cl, Br) nonstochiometry with respect to the cations M was observed. The copper content of 1 and 2 was derived from the site occupation factors of the respective structure refinements. For several crystals examined the copper content varied between x = 0.27 and 0.17 for 1 and x = 0.04 for 2. In both structures the oxochlorotungstate strands are negatively charged and connected to layers by the monovalent copper ions, which are tetrahedrally coordinated by the non‐bridging chlorine atoms of the strands. The structure models imply disorder of the Cu+ ions over closely neighboured sites.

Mixed Valence Tungsten (IV,V) Compounds with Layered Structures (Part III) [2]: Synthesis and Crystal Structure of Ag1–x[W2O2Cl6] and Investigations on the Ag+ Ion Mobility

“…In preceding works we reported on the structure of WOCl 3 and the structures and properties of the chlorooxotungstates M x [W 2 O 2 Cl 6 ] with M = Tl + , K + , Pb 2+ , Hg 2+ and the non‐stoichiometric phases Ag 0.8 [W 2 O 2 Br 6 ] 1, Cu 1– x [W 2 O 2 Cl 6 ], and Cu 1– x [W 4 O 4 Cl 10 ] 2. All compounds represent a family of mixed valence compounds with structures built of negatively charged infinite W 2 O 2 X 6 double strands consisting of WO 2 X 4 octahedra condensed by two edge‐sharing halogen atoms to form double octahedra and corner‐sharing oxygen atoms to build 1D strands.…”