The Infra-Red and Raman Spectra and the Thermodynamic Properties of Diborane

Deuterated diborane has been prepared by isotopic exchange and its infra-red absorption spectrum measured. The Teller-Redlich product rule ratios lend support to the assignment based on the protonated double bond or bridge model. Redetermination of the Raman spectrum of normal diborane indicates several changes from previous assignments of Anderson and Burg and Wagner. The resulting vibrational assignment was used to calculate the thermodynamic properties of diborane in the range 100−1500°K. The ΔHf0, ΔSf0, and ΔFf0 are also given. Appendix I shows that a quadratic potential term arises for the puckering of a planar ring if the ring is strained.