Date of Award
Doctor of Philosophy
John D. Corbett
Previous research into the alkali-metal-gallium systems has revealed a large variety of networked gallium deltahedra. The clusters are analogues to borane clusters and follow the same electronic requirements of 2n + 2 skeletal electrons for closo-deltahedra. This work has focused on compounds that do not follow the typical electron counting rules;The first isolated gallium cluster was found in Cs8Ga11. The geometry of the Ga117- unit is not deltahedral but can be described as a penta-capped trigonal prism. The reduction of the charge from a closo-Ga1113- to Ga117- is believed to be the driving force of the distortion. The compound is paramagnetic because of an extra electron but incorporation of a halide atom into the structure "captures" the unpaired electron and forms a diamagnetic compound. A second isolated cluster has been found in Na10Ga10Ni where the tetra-capped trigonal prismatic gallium is centered by nickel Stabilization of the cluster occurs through Ni-Ga bonding;A simple two-dimensional network occurs in the binary K2Ga3. Octahedra are connected through four waist atoms to form a layered structure with the potassium atoms sitting between the layers. Na30.5Ga60-xAgx is nonstoichiometric and needs only a small amount of silver to form (x~2-6). The structure is composed of three different clusters which are interconnected to form a three-dimensional structure. The RbGa3-xAux system is also nonstoichiometric with a three-dimensional structure composed of Ga8 dodecahedra and four-bonded gallium atoms. Unlike Na30.5Ga60-xAgx, the RbGa3 binary is also stable. The binary is formally a Zintl phase but the ternary is not. Some chemistry in the alkali-metal-indium system also has been explored. A new potassium-indium binary is discussed but the structure has not been completely characterized.
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/
Robert William Henning
Henning, Robert William, "Zintl cluster chemistry in the alkali-metal-gallium systems " (1998). Retrospective Theses and Dissertations. 11615.