Abstract: | The reaction of W6Br12, NaBr, and WO2Br2 in the presence of Br2 in a sealed silica tube yields NaW2O2Br6] together with WOBr4 and WO2Br2 in the low temperature zone (temperature gradient 1030/870 K). NaW2O2Br6] crystallizes orthorhombically in the space group Immm (no. 71) with a = 3.775 Å, b = 10.400 Å, c = 13.005 Å and Z = 2. Pairs of condensed trans-WO2Br4] octahedra with a common Br2 edge form along 100] double chains W2O4/2Br6]1– via the oxygen atoms. The mixed valent tungsten atoms are bonded to W2 pairs with a 2 c–3 e bond (d(W–W) = 2.946 Å, d(W–O) = 1.888 Å, d(W–Brb) = 2.537 Å, d(W–Brt) = 2.535 Å, ∢O–W–O = 177.4°, ∢Brb–W–Brb (endocyclic) = 109.0°). The Na+ cations connect the anionic double chains to form two-dimensional layers parallel (001), which interact by van der Waals forces. The cations are eightfold coordinated by a cube of the terminal Brt ligands of the polymeric anions (d(Na–Br) = 3.138 Å). NaW2O2Br6] may be discussed as an intercalation compound of the oxide bromide WOBr3. |