C. Imrie et al., STRUCTURAL STUDY ON QUASI-PHOSPHONIUM SALTS CONTAINING PHOSPHORUS OXYGEN, PHOSPHORUS-NITROGEN AND PHOSPHORUS SULFUR BONDS, Journal of physical organic chemistry, 8(1), 1995, pp. 41-46
The crystal and molecular structures of six quasi-phosphonium salts co
ntaining phosphorus-heteroatom (heteroatom = oxygen, sulphur or nitrog
en) bonds were determined. Comparison of the molecular parameters obta
ined with those available for reference structures demonstrated that t
he 'double bond' character for the P+ - Y bond decreases in the order
Y = N much greater than O > S.