Quadrivalence :: Quadrivalence (n.) The quality or state of being quadrivalent; tetravalence.
Quadrivalent :: Quadrivalent (a.) Having a valence of four; capable of combining with, being replaced by, or compared with, four monad atoms; tetravalent; -- said of certain atoms and radicals; thus, carbon and silicon are quadrivalent elements..
Trivalence :: Trivalence (n.) The quality or state of being trivalent.
Trivalent :: Trivalent (a.) Having a valence of three; capable of being combined with, substituted for, or compared with, three atoms of hydrogen; -- said of triad atoms or radicals; thus, nitrogen is trivalent in ammonia..
Unrivaled :: Unrivaled (a.) Having no rival; without a competitor; peerless.