Example – KNbW2O9
Polar Hexagonal Tungsten Bronze-Type Oxides: KNbW2O9, RbNbW2O9, and KTaW2O9
H. Y. Chang, T. Sivakumar, K. M. Ok and P. Shiv Halasyamani
Inorg. Chem., 2008, 47 (19), pp 8511–8517
Distorted corner-connected W/NbO6 octahedra to built hexagonal channels, in which pottasium ions are located.