Knowledge Bank

We have studied a long-known but unanalyzed system of bands in the region 360-450 nm caused by an elusive species in unsaturated sulfur at $300\circ C$ to $650\circ C$. All vibrational band heads fit a progression of $v\prime \prime \sim 400cm-1$ and $v\prime \sim$ 640 $cm-1$. The origin, located with the help of $\mathrm{<mrow\; data-mjx-texclass="ORD">34</mrow>}$S, is at 23 601 $cm-1$. The vapor species is here identified as $S3$ thiozone, because the spectrum can be obtained in a krypton matrix at $20\circ K$ and in an organic glass at $77\circ K$ when $S3Cl2$ is photolyzed at low temperature. A continuum in the absorption spectrum of sulfur vapor in the 530 nm region is shown to be due to $S4$, which can be synthesized by the photolysis of $S4$ $Cl2$ in a low temperature glass.