Why are [P(C6H5)4]+N3- and [As(C6H5)4]+N3- Ionic Salts and Sb(C6H5)4N3 and Bi(C6H5)4N3 are Covalent Solids? A Theoretical Study Provides an Unexpected Answer

Abstract

A recent crystallographic study has shown that, in the solid state, P(C6H5)4N3 and As(C6H5)4N3 have ionic [M(C6H5)4]+N3- type structures, whereas Sb(C6H5)4N3 exists as a pentacoordinated covalent solid. Using the results from density functional theory, lattice energy (VBT) calculations, sublimation energy estimates, and Born-Fajans-Haber cycles, it is shown that the maximum coordination numbers of the central atom M, the lattice energies of the ionic solids, and the sublimation energies of the covalent solids have no or little influence on the nature of the solids. Unexpectedly, the main factor determining whether the covalent or the ionic structures are energetically favored, is the first ionization potential of [M(C6H5)4]. The calculations show that at ambient temperature the ionic structure is favored for P(C6H5)4N3 and covalent structures are favored for Sb(C6H5)4N3 and Bi(C6H5)4N3, while As(C6H5)4N3 presents a borderline case.

Open PDF

Document Details

Document Type
Technical Report
Publication Date
Mar 04, 2011
Accession Number
ADA542028

Entities

People

  • David A. Dixon
  • Edward B. Garner
  • H. D. Jenkins
  • Jerry A. Boatz
  • Karl O. Christe
  • Ralf Haiges

Organizations

  • University of Southern California

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Air Force
  • Air Force Facilities
  • Air Force Research Laboratories
  • Antimony Compounds
  • Boiling Point
  • Chemistry
  • Computational Chemistry Methods
  • Crystal Structure
  • Density Functional Theory
  • Department Of Defense
  • Energy
  • Ionization
  • Ionization Potentials
  • Military Research
  • Quantum Chemistry
  • Sublimation
  • Thermodynamics

Readers

  • Nanocomposite Materials Science
  • Organic Chemistry
  • Plasma Physics.