MOLECULAR-STRUCTURE OF SBF3 AND BIF3 - AN ELECTRON-DIFFRACTION STUDY

The molecular structure of gaseous SbF3 and BiF3 was determined by gas -phase electron diffraction. The principal geometrical parameters are r(g)(Sb-F) 1.880 +/- 0.004 Angstrom, r(alpha)(Sb-F) 1.876 +/- 0.004 An gstrom, angle(alpha)F-Sb-F 94.9 +/- 0.2 degrees and r(g)(Bi-F) 1.987 /- 0.004 Angstrom, r(alpha)(Bi-F) 1.979 +/- 0.004 Angstrom, angle(alph a)F-Bi-F 96.1 +/- 0.6 degrees, respectively. They are consistent with the expected trends of geometrical variations in the Group 15 trihalid e series, except for the bond angle of BiF3. It is suggested that the highly ionic character of BiF3 may be responsible for its larger than expected bond angle. (C) 1997 Elsevier Science B.V.