Cobaltous /(?)/

Co·balt·ous

Cobaltous

a.
  1. Pertaining to, derived from, or containing, cobalt; -- said esp. of cobalt compounds in which the metal has its lower valence. (Chem.)

Phrases & Compounds
Cobaltous chloride
a crystalline compound, CoCl2, of a pale rose color when hydrous, blue when dehydrated. Its solution is used for a sympathetic ink, the writing being nearly colorless when dried in the air, owing to absorbed moisture, and becoming bright blue when warmed.