Degree Type

Dissertation

Date of Award

1981

Degree Name

Doctor of Philosophy

Department

Chemistry

Abstract

Several new, reduced ternary and quaternary oxides of molybdenum are reported, each containing molybdenum in an average oxidation state < 4.0. All of these compounds contain either discrete molybdenum atom clusters or infinite chains of bonded molybdenum atoms;The compounds ScZnMo(,3)O(,8), LiZn(,2)Mo(,3)O(,8), and Zn(,3)Mo(,3)O(,8) have been synthesized and crystal structures have been determined for the latter two. These oxides contain the same type of triangular molybdenum atom clusters found in the compound Zn(,2)Mo(,3)O(,8) (McCarroll, W. H. ; Katz, L; Ward, J. J. Am. Chem. Soc. 1957, 79, 5410). However, each of the trimeric clusters in these new compounds has available one or two additional electrons for participation in metal-metal bonding;Another newly prepared and characterized ternary oxide containing discrete metal atom clusters is Ba(,1.14)Mo(,8)O(,16). The structure of this compound consists of molybdenum-oxide cluster chains extended parallel with the c axis. These chains are built from clusters of the type Mo(,4)O(,16) sharing the oxygen atoms on the four outer edges of the planar tetrameric molybdenum atom cluster to give an Mo(,4)O(,8) stoichiometry. Two different infinite chains, built up from Mo(,4)O(,8)('2-) and Mo(,4)O(,8)('0.28-) cluster units, respectively, are interlinked via Mo-O-Mo bridge bonding to create four-sided tunnels in which the Ba('2+) ions reside;The new compound NaMo(,4)O(,6) contains infinite chains of bonded molybdenum atom clusters. These chains are comprised of clusters of the type Mo(,6)O(,12) fused at opposite edges by removal of two edge-bridging oxygen atoms, and sharing of the metal and remaining oxygen atoms between cluster units. The sodium ions occupy sites in channels formed by four molybdenum-oxide cluster chains crosslinked by strong Mo-O-Mo bonds;Another new compound, whose structure is closely related to that of NaMo(,4)O(,6), is Ba(,0.62)Mo(,4)O(,6). This material also exhibits a superlattice ordering of barium ions within the channels. An analysis of this superstructure from single crystal x-ray diffraction data is discussed;Other compounds that have been prepared and also partiallycharacterized by chemical analyses and x-ray powder diffractiondata are tentatively formulated as K(,2+x)Mo(,12)O(,19), Na(,2+x)MO(,12)O(,19),and CaMo(,5)O(,8);('1)DOE Report IS-T-960. This work was performed under Contract W-7405-eng-82 with the Department of Energy.

DOI

https://doi.org/10.31274/rtd-180813-5703

Publisher

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

Copyright Owner

Charlie Carmine Torardi

Language

en

Proquest ID

AAI8128865

File Format

application/pdf

File Size

179 pages

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