IS SIS2 THE CARRIER OF THE UNIDENTIFIED 21-MICRON EMISSION FEATURE

Spectra are presented of SiS2 samples in a variety of crystal forms ta ken at both room temperature and at 600 K over the wavelength range fr om 5-25 microns. All spectra show strong features at 22.5 and 9.5 micr ons as well as less intense bands at 7.5, 8.5, and 12.5 microns. All r oom temperature spectra also show a feature at 10.7 microns that disap pears on heating. One form of SiS2 shows strong correlated absorption features at 20 and 17 microns that are rapidly quenched by exposure to humid air with no significant change to the 7-13 and 22 micron featur es also present in the sample. These SiS2 spectra are consistent with previous spectra obtained by Nuth et al. (1985), are marginally consis tent with the identification of SiS2 as the source of the observed 21 micron peak in several carbon-rich stellar sources, and suggest additi onal observations of these stellar sources that might confirm or refut e the presence of SiS2. Specifically, if no feature at 17 microns is d etected in objects that display the strong 21 micron emission feature then SiS2 should be ruled out as a candidate for this band.