What is 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 called?

trivalent — 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. (Webster's 1913.)

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