▪ I. trihydric, a.1 Chem.
(traɪˈhaɪdrɪk)
[f. tri- 5 + Gr. ὕδωρ water + -ic.]
Containing three hydroxyl groups, OH; thus glycerin or glycerol, C3H5(OH)3, is a trihydric alcohol; pyrogallic acid or pyrogallol, C6H3(OH)3, is a trihydric phenol.
| 1866 Frankland Lect. Notes 269 Relations of Glycerin to the Trihydric Acids, Glyceric Acid,..and Tartronic Acid. 1881 Frankland & Japp Lect. Notes (ed. 3) II. 105 Trihydric Alcohols. Glycerin..series. These alcohols contain three semimolecules of hydroxyl. 1900 Smith Richter's Org. Chem. (ed. 3) II. 140 The phenols, like the alcohols, are distinguished as mono-, di-, and trihydric, according to the number of hydroxyl groups which have entered. |
▪ II. trihydric, a.2 Chem.
= trihydrogen (which is now preferred).
| 1866 Roscoe Elem. Chem. xv. 136 The three atoms of hydrogen in trihydric [ed. 1869 trihydrogen] phosphate may be replaced by three different metals. 1887 Tidy Modern Chem. (ed. 2) 163. |