The h ‐Sb x WO 3+2 x Oxygen Excess Antimony Tungsten Bronze

We describe the previously unreported oxygen excess hexagonal antimony tungsten bronze with composition Sb 0.5 W 3 O 10 , in the following denoted as h ‐Sb x WO 3+2 x with x =0.167, to demonstrate its analogy to classical A x WO 3 tungsten bronzes. This compound forms in a relatively narrow temperature range between 580 °C< T <620 °C. It was obtained as a dark‐blue polycrystalline powder, and as thin, needle‐shaped, blue single crystals. h ‐Sb x WO 3+2 x crystallizes in the hexagonal space group P 6/ mmm with the cell parameters a =7.4369(4) Å and c =3.7800(2) Å. The antimony and excess oxygen occupy the hexagonal channels within the network of corner‐sharing WO 6 octahedra. h ‐Sb x WO 3+2 x has a resistivity of ρ 300 K ≈1.28 mΩ cm at room temperature, with little if any temperature‐dependence on cooling. DFT calculations on a simplified model for this compound find a metallic‐like electronic structure with the Fermi level falling within rather flat bands, especially around the Γ point.