Structural Investigation by Means of Nuclear Quadrupole Resonance III (Arsenic Tribromide)

The structure of AsBr 3 is investigated by means of nuclear quadrupole resonance at about 10°C, and is compared with Braekken's results of X-ray analysis. AsBr 3 has the orthorhombic symmetry, and the Br–As–Br bond angles are 99°38'±16', 99°14'±18' and 102°51'±13'. The polar angles specifying the directions of the As-Br bonds with respect to the crystal axes are (62°4'±13', 56°9'±8'), (64°7'±15', -61°46'±11'), and (61°54'±8', 180°50'±20). The bond angles are larger than those of Braekken by about 1°. The asymmetry parameter of field gradient at the bromine nucleus is about 0.04±0.02. Single, double, and ionic character of As–Br bond are 61.4%, 1.2% and 37.4%, respectively, and the bond length is deduced to be 3.20 A. These results are consistent with those of X-ray analysis except the slight disagreement in the bond angles.