Degree Type

Dissertation

Date of Award

1989

Degree Name

Doctor of Philosophy

Department

Chemistry

First Advisor

Robert E. McCarley

Abstract

Low temperature routes were used to synthesize tungsten and molybdenum nitride precursors from metal chlorides and nitrogen-containing compounds. A number of reactions in ammonia and organic solvents were undertaken to prepare tungsten and molybdenum nitrido precursors. These compounds were then treated at moderate temperatures (200-500°C) to form the nitride compounds. During the heat treatment of one of the precursors, a tungsten imide bronze species was discovered. A Reitveld refinement of the x-ray powder data was performed and the structure was found to be similar to the Rb[subscript]0.27WO[subscript]3 tungsten bronze (Magneli A; Acta Chem. Scand. 1953, 7, 315);The syntheses of NdMo[subscript]8O[subscript]14 and some of its rare earth analogues were performed at high temperatures in sealed molybdenum and fused silica tubes. The structure of NdMo[subscript]8O[subscript]14 contains discrete bicapped octahedral cluster units, but the cluster units are interconnected in such a way that a relatively short intercluster Mo-Mo distance of 3.059 A results. Magnetic susceptibility and resistivity measurements indicated an interaction between the cluster units which leads to electron delocalization and metallic character. These data thus indicate that the short intercluster distance represents a bonding interaction;Large single crystals of the intermetallic compounds Ni[subscript]2.43Fe[subscript]4.57Mo[subscript]6 were observed as products in a high temperature reaction which involved various oxygen containing species. The compound was found to be similar to Co[subscript]7Mo[subscript]6 (Forsyth, J. B; d'Alta de Veiga, L. M; Acta Crystallogr. 1962, 15, 433). The single crystal x-ray refinement shows that the compound is composed of layers of molybdenum and mixed layers of nickel and iron. Very short metal-metal distances were observed in the compound.

DOI

https://doi.org/10.31274/rtd-180813-11732

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Clark Dale Carlson

Language

en

Proquest ID

AAI9014887

File Format

application/pdf

File Size

126 pages

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