Molecular vibrations of zirconium(IV) tetrahydroborate, a compound containing triple hydrogen bridges

Abstract

The i.r. and Raman spectra of Nujol solutions and solid samples of both Zr(BH₄)₄ and Zr(BD₄)₄ are reported. The assignments of the observed spectra are discussed on the basis of both T and T_d symmetry point groups. Significant contributions to the Zr(BD₄)₄ spectra of ¹H-containing species are observed. A modified valence force field incorporating an explicit Zr–B stretching force constant (1.5 mdyn Å^–1) is developed. Qualitative descriptions of the normal vibrations are made on the basis of calculated potential-energy distributions.