Refinement of the structure of ?-Nb2O5 and its relationship to the rutile and thoreaulite structures

Autor: T. S. Ercit
Rok vydání: 1991
Předmět:
Zdroj: Mineralogy and Petrology. 43:217-223
ISSN: 1438-1168
0930-0708
Popis: The crystal structure of ζ-Nb2O5, space groupC2/c, a 12.740(2),b 4.8830(6),c 5.5609(6)A,β 105.02(1)°, Z 4, has been refined toR 1.6% for 457 observed reflections (MoKα). The coordination polyhedron of the niobium atom is a distorted octahedron; the crystal structure consists of two-octahedron-thick, rutile-like layers separated by crystallographic shear (CS) planes. Relative to the rutile structure, these planes are indexed (101) and adjacent layers are related by the CS vector . Members of the thoreaulite-foordite series have topologically identical two-octahedron-thick (101) sheets; however, here the CS vector r, coupled with the translation vector r results in the insertion of a plane of square antiprism interstices between adjacent octahedral sheets.
Databáze: OpenAIRE