Ab initio studies are presented for metaphosphate ion, P03- (1), and tris(methylene)metaphosphate ion, P(CH2)3- (2). Using good basis sets at the SCF level, the minimum energy structure of 2 is a D3structure with the CH2groups twisted by 19° from the molecular plane, but this structure lies only 1 kcal mol-1below the constrained D3hplanar structure. Inclusion of electron correlation increases this energy difference by only 1 kcal mol-1. The charge distributions correspond to highly polar structures with large negative charges on the oxygens and methylene groups of P03- and P(CH2)3-, respectively. The best simple representation of these compounds is as dipolar structures; double bonding to phosphorus is relatively weak.
ASJC Scopus subject areas
- Colloid and Surface Chemistry