a. Chem. [f. Gr. τετρα-, TETRA- + L. valēnt-em, pr. pple. of valēre to be worth.] Combining with four atoms of hydrogen or other monovalent element, or with four monovalent radicals, or capable of replacing four atoms of monovalent elements in a compound; thus the atoms of carbon and of lead are tetravalent in the compounds CH4, Pb(C2H5)4. Also called quadrivalent. So Tetravalence, the quality or fact of being tetravalent; quadrivalence.
1868. Williamson, Chem. for Students, 124. Oxygen is … called a divalent element. A similar reasoning shows nitrogen to be trivalent; and carbon is tetravalent.
1887. Athenæum, 13 Aug., 217/1. Proof is thus afforded that these elements [sulphur and selenium] are at least tetravalent in function.
