Abstract
The inverse-first moment and the first moment of the observed optical-absorption spectrum of the crystalline electride [Cs(18-crown-6
)
2
] [where (18-crown-6) is (
CH
2
CH
2
O
)
6
] are used to determine rigorous upper and lower bounds for the absolute maximum of the single-particle probability density of a typical constituent electride electron. These bounds sufficiently bracket the contact densitites that are determined from magic-angle-spinning
133
NMR
spectra of the pure electride and of its mix-crystals with the isomorphous sodide, [Cs(18-crown-6
)
2
Na], to indicate that the distribution of the electron most likely is located in the immediate vicinity of a cesium nucleus. Limitations on the number of
133
NMR
absorptions in sodide-electride mix-crystals are shown to support such a location.