MNDO calculations for some allotropes, hydrides, and oxides of phosphorus

Abstract

N. COLIN BAIRD. Can. J. Chem. 62, 341 (1984).Molecular orbital calculations by the MNDO method are reported for some allotropes, hydrides, and oxides of phosphorus. The aim of the study is to test further the ability of MNDO to reproduce the energetics of PP, PH, and PO bonds, and to apply MNDO to interesting problems in the chemistry of such systems. Different isomers of P,, P6, and P, are considered, as well as ions of P,, Pj, and P7. The method is found to overestimate strain energy in three-membered rings, and to underestimate the strength of three-electron PP bonds. The strength of PO 7~ bonds apparently also is overestimated. Introduction Although sophisticated ab initio molecular orbital calculations are becoming feasible for larger and larger systems, semiempirical MO computations still are useful in many contexts -including reaction mechanisms and the study of molecules which contain many electrons. Two methods which are claimed to be sufficiently accurate and general for most purposes are the MIND0 and MNDO schemes developed by Dewar and co-workers (1). Recently we have initiated a study of the use of the MNDO method in the field of covalent inorganic chemistry and have reported on applications to the various forms of elemental sulfur (2). In the present report we extend our analysis to the catenation behavior of phosphorus, and to some phosphorus oxides.

Structure and bonding in the isoelectronic series CnHnP5−n+: is phosphorus a carbon copy?

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Synthesis of rhodium-containing heterobimetallic hydride complexes

“…The most likely explanation of everything we have observed is one that assumes the transition involves at least three or more domains. For example there could be three domains of the following types: (1) all high spin; (2) half high spin and half low spin; (3) all low spin. Each of these phases would have a particular set of ZFS parameters for the impurity Mn(II), and there would be a gradual change in the quantity of each phase as the temperature changes through the crossover region.…”

Measurement of Interface Level, Holdup, Pulsation Frequency, and Amplitude in a Pulsed Column by Air Purge

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