The Collaborative International Dictionary of English v.0.48:

Divalent \Div"a*lent\, a. [Pref. di- + L. valens, valentis, p.
   pr. See Valence.] (Chem.)
   Having two units of combining power; bivalent. Cf. Valence.
   [1913 Webster]

WordNet (r) 3.0 (2006):

divalent
    adj 1: having a valence of two or having two valences [syn:
           bivalent, divalent]