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Tantalum‐Niobium Mixing in Ta 3–x Nb x TeI 7 (0 ≤ x ≤ 3)
Author(s) -
Smith Mark D.,
Miller Gordon J.
Publication year - 2000
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/(sici)1521-3749(200001)626:1<94::aid-zaac94>3.0.co;2-2
Subject(s) - tantalum , niobium , crystallography , chemistry , structure type , crystal structure , stacking , metal , organic chemistry
A substitutional study of the layered, trinuclear metal cluster system, Ta 3–x Nb x TeI 7 (0 ≤ x ≤ 3), has been performed. Synthetic, crystallographic, and spectroscopic results are presented for starting compositions corresponding to the x values: 1, 1.5, and 2. For the entire composition range studied, Ta(Nb) could readily substitute into the Nb(Ta) 3 TeI 7 structure, but with changes in the observed stacking arrangements of the layers as x varies. For tantalum‐rich (x ≤ 1.8) phases, the structure conformed to the Nb 3 SeI 7 structure type, also adopted by Ta 3 TeI 7 and one polytype of Nb 3 TeI 7 . Niobium‐rich (i. e. x ≥ 1.7) phases were observed to adopt two structure types according to X‐ray powder diffraction, but crystals could only be obtained for the Nb 3 SBr 7 structure type, which is a second modification of Nb 3 TeI 7 . Extended Hückel calculations are used to discuss the distribution of metal clusters in this system.