Comparative PM3-M0 Study of the E₂O₂ and E₂N₂ (E=P,As) Four Membered Ring Systems

Abstract

It seems that the relative stability of the E₂O₂ and E₂N₂ (E=P,As) rings is mainly determined by the different weights of the oxygen and nitrogen p orbitals to the HOMO's of these systems which in turn reflects a more favourable orbital mixing in the rings where the difference of the electronegativity of the constituents is smaller. This might explain the great diversity of the cyclodiphosphazane (arsazane) rings comparatively to the cyclodiphosphoxane (arsoxane) rings.

Keywords::

• cyclodiposphazanes
• cyclodiphosphoxanes
• cyclodiarsoxanes
• cyclodiarsazanes
• PM3 molecular orbital calculations