Knowledge Bank

Complete infrared and Raman spectra have been obtained for the four molecules $S-B(X)-S-B(X)-S⏞$, with $X=C1,Br,I,CH3$. The results provide good evidence (but not proof) that the molecules are planar and have $C2\nu$ symmetry. The presence of boron isotopes splits some of the higher bands, and this is helpful in assigning them. Assignments have been made for 57 of the 60 fundamentals of the $\mathrm{<mrow\; data-mjx-texclass="ORD">11</mrow>}B-11B$ isotopic molecules. About 2/3 of these are reliable, while the remainder are more or less questionable. The S-S stretching frequencies are 449, 436, 425, and 479 $cm-1$ respectively.