EXTENDED MO-NB BONDS IN K5.3MO9.2NB0.8O30 - A MOLYBDENUM BRONZE WITH THE TETRAGONAL (I) TUNGSTEN BRONZE STRUCTURE

K5.3Mo9.2Nb0.8O30 crystallizes in the tetragonal system, space group P4/mbm. The unit cell dimensions are a = 12.5591(9) Å, c = 3.976(1) Å, V = 627.2(2) Å3, and Z = 1. The structure was refined to R = 0.021, Rw = 0.032, with 321 observed reflections (I > 3 σ(I)) and 51 variable parameters. The structure of K5.3Mo9.2Nb0.8O30 is of the tetragonal (I) tungsten bronze type with Nb partially occupying the trigonal interstitial sites forming infinite zigzag chains of Nb-Mo bonds along the crystallographic c-axis. © 1993 Academic Press, Inc.