<p> The crystal structures of four compounds of the type (Zn,Cd,Mn)3(PO4)2 have been determined by X-ray diffraction methods. These structures are the high temperature (β) phase of Zn3(PO4)2, the related structures of β1-Mn3(PO4)2 and β1-Cd3(PO4)2, and the structure of a member of a solid solution of median composition Zn2Cd(PO4)2 which is similar in structure to the mineral graftonite. The orthophosphates of the small divalent metal ions have been separated into four structure classes and the stability of each of these classes is discussed in terms of cation concentration and the types of cation sites which exist in these structures. The correlation of a host crystal structure and the luminescence of Mn++ when this ion is added as an impurity is also discussed.</p> / Thesis / Doctor of Philosophy (PhD)

Conversion of 1-Methylpentacyclo[5.4.0.0²⋅⁶.0³⋅¹⁰.0⁵⋅⁹]undecane- 8,11-dione into the corresponding mono(ethylene ketal) followed by Wolff-Kishner reduction resulted in a mixture of two isomers (i.e., 1- and 7-methyl-8-[2',-(1',3',dioxolano)]pentacyclo[5.4.0.0²⋅⁶.0³⋅¹⁰.0⁵⋅⁹] undecane. Hydrolysis of each isomer in turn resulted in 1- and 7- methyl pentacyclo[5.4.0.0²⋅⁶.0³⋅¹⁰.0⁵⋅⁹ ]undecan-8-ones (i.e.,"methylated PCU-8-ones"), respectively. "Titanium-promoted reductive dimerization of each of the methylated pentacycloundecane (PCU)-8-ones afforded mixtures of "methylated PCU alkene dimers". Individual isomers have been isolated from these mixtures via column chromatography by using silver nitrate impregnated silica gel as adsorbent followed by fractional recrystallizations of individual chromatography fractions. Structures of three isomerically pure methylated PCU alkene dimers (C₂₄H₂₈) have been established unequivocally by application of single crystal X-ray crystallographic methods.