X-ray crystallographic structures are reported for 1(Me)(2+)(SbCl6-)(2)center dot 2CH(3)CN, 2(Et)(2+) (SbF6-)(2)center dot 2CH(3)CN center dot 2CH(2)Cl(2), and 1(iPr)(2+)(SbF6-)(2), which also contained unresolved solvent and is in a completely different conformation than the methyl- and ethyl-substituted compounds. A quite different structure of 1(Me)(2+)(SbF6-)(2) than that previously published was obtained upon crystallizing it from a mixture rich in monocation. It does not contain close intramolecular PD+,PD+ contacts but has close intermolecular ones. Low temperature NMR spectra of 1(Me)(2+) and 1(Et)(2+) in 2:1 CD3OD/CD3CN showed that both contain three conformations of all-gauche NCCC unit material with close intramolecular PD+,PD+ contacts. In addition to the both PD+ ring syn and anti material that had been seen in the crystal structure of 1(Me)(2+)(SbF6-)(2)center dot 2CH(3)CN published previously, an unsymmetrical conformation having one PD+ ring syn and the other anti (abbreviated uns) was seen, and the relative amounts of these conformations were significantly different for 1(Me)(2+) and 1(Et)(2+). Calculations that correctly obtain the relative amounts of both the methyl- and ethyl-substituted material as well as changes in the optical spectra between 1(Me)(2+) and 1(Et)(2+), which contains much less of the uns conformation, are reported.