osmous

enUK

os·mous

O0138600 (ŏz′məs) also os·mi·ous (-mē-əs)adj. Relating to or containing osmium in a compound with a valence lower than that in a comparable osmic compound.
[osm(ium) + -ous.]

osmous

(ˈɒzməs) adj (Chemistry) of or containing osmium in a low valence state, esp the divalent state. Also: osmious