I just came across the term cobaltosic for the first time in the abstract of Ind Eng Chem Res 52(18): 6076, 2013 (emphasis added):
A nanocomposite of cobaltosic oxide and nitrogen-doped graphene ($\ce{Co3O4}$/N-G) was prepared by the facile hydrothermal method.
I assume this is a historical name; Wikipedia's article on the cobalt spinel mentions cobaltosic oxide as an "other name", but provides no other historical information. Google searches on manganosic oxide and ferrosic oxide turn up the sort of results I would expect, though not all consistent:
Manganese
- Analogous to cobalt, manganosic oxide appears to be the $\ce{Mn3O4}$ spinel; e.g., see the abstract here (PDF at link).
Iron
- The term ferrosic appears to refer (at least) to a mixed-oxidation state hydroxide, $\ce{Fe3(OH)8}$; e.g., here.
- However, it is also used to refer to the iron $\ce{Fe3O4}$ spinel (magnetite); e.g., here.
What is the meaning of this "-osic" suffix?