The Borohydride Ion in the Lithium Borohydride Lattice

Abstract

IN a recent communication in Nature, Dr. C. J. H. Schutte¹ has suggested that the anomalous band occurring at about 1,250 cm.⁻¹ in the paraffin-oil mull spectrum of lithium borohydride at room temperature² may be assigned to the doubly degenerate frequency, ν̄₂(E), of tne tetrahedral ${\text{BH}}_{{\text{4}}^{\text{−}}}$ ion. This frequency is normally inactive in the infra-red, but it is suggested that under the space-group V _h of crystalline, orthorhombic lithium borohydride, the ${\text{BH}}_{{\text{4}}^{\text{−}}}$ ions occupy sites of symmetry C _s; the degeneracy is thereby removed so that all the fundamentals are now allowed.