The Band Spectrum of Antimony Chloride

A band spectrum attributed to the molecule SbCl, in the region $\lambda \lambda 4200-5600$, has been excited by introducing Sb${\mathrm{Cl}}_3$ into active nitrogen. No other bands appeared in the range $\lambda 2000$ to $\lambda 7000$. The spectrum consists of bands showing pronounced progressions and degraded towards the red. They can be placed in two sub-systems of bands, designated as $A_1$ and $A_2$. Vibrational analysis shows that within experimental error the wave numbers of the heads of forty-one bands of Sb${\mathrm{Cl}}^{35}$ are represented by the formulas: $A_1:{\nu }_1=22395+244.4\mathrm{}{u}^{\prime }-2.28\mathrm{}{u}^{\prime 2}-368.0\mathrm{}{u}^{\prime \prime }+0.84\mathrm{}{u}^{\prime \prime 2},$ $A_2:{\nu }_2=25855+240.2\mathrm{}{u}^{\prime }-2.19\mathrm{}{u}^{\prime 2}-370.0\mathrm{}{u}^{\prime \prime }+1.00\mathrm{}{u}^{\prime \prime 2}.$ The chlorine isotope effect appears in 13 bands and is used to confirm the $v^{\prime }$, $v^{\prime \prime }$ designations. The analysis of the spectrum given here is somewhat different from that originally presented two years ago. Many more bands are here accounted for and identified. An attempt failed to produce a spectrum of AsCl by introducing As${\mathrm{Cl}}_3$ vapor into active nitrogen.