titanous

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Relating to or containing titanium, especially with valence 3.

from The Century Dictionary.

• In chem., containing titanium as a constituent with apparently dyad valence, as titanous sulphate (Ti₂(SO₄)₃).

from the GNU version of the Collaborative International Dictionary of English.

• adjective Designating certain compounds of titanium in which that element has a lower valence as contrasted with titanic compounds.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective inorganic chemistry Of or pertaining to titanium, especially trivalent titanium