Hans Peter Verne

The molecular structure of trimethyltantalum dichloride, (CH3)3TaCl2, as determined by gas electron diffraction

Abstract The gas electron diffraction data of (CH 3 ) 3 TaCl 2 , recorded with a nozzle temperature of about 25°C, show that the coordination geometry of the metal atom is trigonal bipyramidal with the Cl atoms in axial positions. Least-squares refinements based on a molecular model (hydrogen atoms excluded) of D 3h symmetry yield the bond distances ( r a ) TaC = 215.8(5) pm and TaCl = 231.7(3) pm.

The Molecular Structures and Conformational Preferences of Simple Molecules Containing Bonds Between a Trivalent Group 15 and a Divalent Group 16 Element: The Molecular Structures of Dimethyl(methylthio)stibane and Dimethyl(methylseleno)stibane, (CH3)2SbECH3 E = S or Se, by Gas Electron Diffraction

Gas electron diffraction data of (CH3)2SbECH3 E = S or Se, show that the predominant conformer is one where the dihedral angle defined by the E–C bond, the Sb–E bond and the presumed direction of the lone pair at the Sb atom falls in the range –45 to +45°. The Sb–S and Sb–Se bond distances are 241.4(8) and 255.5(3) pm, respectively.

Molecular Structures of Pentamethylarsenic(V) and Trimethyldichloroarsenic(V) by Gas Electron Diffraction and ab Initio Calculations: Molecular Mechanics Calculations on Pentamethylarsenic(V), Pentaphenylarsenic(V), and Related Compounds

The molecular structures of AsMe5 and AsMe3Cl2 (Me = CH3) have been determined by gas electron diffraction and Hartree−Fock computations. Both molecules are found to have trigonal bipyramidal arrangements of the heavy atom skeleton. The bond distances (ra) for AsMe5 are As−Ceq = 197.5(3) pm and As−Cax = 207.3(4) pm; for AsMe3Cl2, As−Ceq = 192.5(2) pm and As−Clax = 234.9(3) pm. The coordination geometries and dimensions are compared with those of related molecules. Molecular mechanics calculations on the pentamethyl and pentaphenyl derivatives of P, As, Sb, and Bi reproduce the observed coordination geometries and indicate that the square pyramidal equilibrium structures of SbPh5 and BiPh5 are stabilized by Coulombic interactions between the ligands.

The molecular structure of tetramethyloxorhenium, (CH3)4ReO, by gas electron diffraction

Abstract The gas electron diffraction data of tetramethyloxorhenium, (CH 3 ) 4 ReO, recorded with a nozzle temperature of about 30°C are consistent with the molecular symmetry C 4v . Least-square refinements yield the bond distances ( r a ) ReO = 168.2(3) pm and ReC = 211.7(3) pm and the valence angles ∠CReC = 82(1)° and ∠CReO = 112(1)°.