Degree Type

Dissertation

Date of Award

1983

Degree Name

Doctor of Philosophy

Department

Chemistry

Abstract

The investigation of the alkali metal intercalation and nonmetal interstitial derivatives of YCl has produced six new classes of compounds: 3R-Li(,0.09)YCl, 1T-Y(,2)Cl(,2)C, 2H-, and 3R-M(,0.1)('I)YClO, 1T-Cs(,0.1)YClO, and 1T-M(,0.4)('I)Y(,2)Cl(,2)C with M('I) = Li-Cs (except 2H-Li(,0.1)YClO). These are all synthesized as black plates by stoichiometric reaction of Y powder or strips, YCl(,3), and, as appropriate, M('I)Cl, Y(,2)O(,3), YOCl or C within sealed Nb tubing at 950(DEGREES)C for 1-3 weeks. The yields for all but 3R-Li(,0.09)YCl are above 90%;The structures of five new phases have been solved by single crystal methods: 3R-Li(,0.09)YCl, 3R-Na(,0.08)YClO(,1.0), 2H-K(,0.08)YClO(,0.82), 1T-K(,0.52)Y(,2)Cl(,2)C(,0.80), and the parent 3R-YCl. The oxygen or carbon atoms occupy essentially all tetrahedral or trigonal antiprismatic (tap) interstices, respectively, between double Y layers in the four-layered slabs sequenced Cl-Y-Y-Cl. High resolution Guinier powder patterns were also used to identify phases and structures.(,);3R-YCl is isostructural with ZrBr and this is retained in 3R-Li(,0.09)YCl with Li('+) randomly distributed over (TURN)40% of the tap sites between Cl layers. A decrease in the Y-Y distances accompanies the reduction of the slabs, though increasing Y-Cl and Cl-Cl separations cause an overall increase in the c-axis;In 1T-Y(,2)Cl(,2)C the size of the nonmetal requires substitution in the tap site between the Y layers while the second nearest neighbor interactions appear responsible for the reordering of the layers into a hexagonally-close-packed one-slab structure. The intercalated alkali metals in 1T-M(,0.4)('I)Y(,2)Cl(,2)C occupy the tap site between Cl layers within the 1T structure;The different M(,0.1)('I) YClO structures result from the different packing arrangements of slabs about M('I). In the YCl-like 3R structure the tap sites between Cl layers are randomly occupied with M('I) = Li-Cs. In the 2H- (M('I) = Na-Cs) and 1T-structures (M('I) = Cs) the alkali metal has trigonal prismatic coordination;The 3R-M(,0.1)('I)YClO is oxidized by I(,2)/CH(,3)CN to form 3R-YClO(,z) which is isostructural with YOF and ZrBrO(,x). In moist air the 3R phase, M('I) = K or Rb, undergoes reversible hydration to form a;crystalline hydrate, 1T-M(,.01)('I)(H(,2)O)(,a)YClO. In water the 3R phases (M('I) = Li-Cs) are oxidized and the crystals exfoliate; ('1)DOE Report IS-T-1063. This work was performed under contract No. W-7405-Eng-82 with the U.S. Department of Energy.

DOI

https://doi.org/10.31274/rtd-180813-11443

Publisher

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

Copyright Owner

Jeffrey Earl Ford

Language

en

Proquest ID

AAI8407070

File Format

application/pdf

File Size

127 pages

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