Dissociative electron attachment to alkyl halides is employed to searc
h for stable hydrogen halide anions. Anions previously ascribed to HCl
- from 2-chloropropane are here shown to be C-3(-) on the basis of acc
urate mass determinations. Long-lived HI- ions are observed from iodom
ethane, but HBr- is not detected at the part-per-million level from 2-
bromopropane.