Vibrational frequencies and structure of B4Cl4: an ab intio quantum chemical study

The normal mode frequencies and corresponding vibrational assignments of B4Cl4 are examined theoretically using the Gaussian 98 set of quantum chemistry codes. All normal modes were successfully assigned to one of three types of motion predicted by a group theoretical analysis (B-B stretch, B-Cl stretch, B-Cl bend) utilizing the Td symmetry of the molecule. The vibrational modes of the naturally isotopically substituted (1-(10)B, 2-(10)B, 3-(10)B and 4-(10)B) forms of B4Cl4 were also calculated and compared against experimental data. A complex pattern of frequency shifts and splittings is revealed.