The molecular structure of boron trifluoride, BF 3

Abstract

The total number of valence electrons in this compound is 3 + 3 × 7 = 24 = 3 × 8, and in accordance with Zachariasen’s rule (1931) the boron atom should lie at the centre of the triangle formed by the three fluorine atoms. If this total number is expressible as n × 8 + m × 2, then the central atom is displaced from the plane, as in SO 3 --. It was partly with a view to determining whether the extreme ionic nature of fluorine made any difference to this principle that this infra-red investigation was undertaken. The results obtained were completed by the recent publication of the Raman spectrum of this substance (Anderson, Lassettre and Yost 1936) in both the gaseous and liquid states.