dobereiner's triads

  • 11triad — triadic, adj. triadism, n. /truy ad, euhd/, n. 1. a group of three, esp. of three closely related persons or things. 2. Chem. a. an element, atom, or group having a valence of three. Cf. monad (def. 2), dyad (def. 3) …

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