Crystal structure of K 6 CrNb 15 O 42

K 6 CrNb 15 O 42 crystallizes in the hexagonal system with a =9.126 (3) Å, c =12.068(3) Å, V =870.4(5) Å 2 , and space group P 6 2 / mcm, Z =1. The structure was solved using direct method and Fourier Techniques. Of the 829 unique reflections measured by counter techniques, 448 with 1 ≥ 3σ( I ) were used in the least‐squares refinement of the model to R =0.034 ( R w =0.044). The structure of K 6 CrNb 15 O 42 may be described as consisting of corner‐shared and edge‐shared octahedra, the ring units composed of six octahedra of Nb(1) are corner‐shared one another along the c ‐axis to form hexagonal column octahedra chains which are connected by K + and octahedra of Nb(2).