Quantum chemical calculations on the problem of 'stereochemically active' electron pairs

✍ Scribed by Frank Schmitz; Werner Kutzelnigg

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 31 KB
• Volume: 54
• Category: Article
• ISSN: 0022-1139
• DOI: 10.1016/s0022-1139(00)83862-2

✦ Synopsis

Ab-initio pseudopotential and all-electron SCF calculations of the molecules ArF6.

KrF6, XeF6 and the isoelectronic ions ClFs. BrF6-. IFe-have been performed with the TURBOMOLE and the GAUSSIAN90 programs. Geometry optimisation in Cj, symmetry leads for XeF6 to a distorted structure, for KrF6 to a slight distortion from &geometry, but for the other systems to regular octahedra. The results are very sensitive to the level of computational sophistication. Electron correlation stabilises regular structures. IF6 appears to be a critical case. The agreement between computed and experimental bond lengths (if available) is satisfactory. Some attempts are made to analyse what determines whether or not an electron pair is stereochemically active.