| 释义 |
tribasic, a. Chem.|traɪˈbeɪsɪk|
[f. Gr. τρι-, tri- + βάσ-ις base + -ic.]
Having three bases.
1. Of an acid: Having the property of exchanging three atoms of hydrogen for three of potassium or sodium, and thus forming a salt; e.g. phosphoric acid, H3PO4, which reacts with sodium hydroxide, NaOH, forming trisodium phosphate, Na3PO4. Of a salt: Containing three molecules of the basic oxide; e.g. tribasic lead acetate.
In the first half of the 19th c., the acid oxide was considered to be the acid itself (not as now when acid means the compound of this oxide with water), and tribasic acid was applied to an oxide which united with three equivalents of base to form a salt: hence the name.
1837Graham in Phil. Trans. 62 A new nomenclature of these salts..I offer for consideration..Tribasic phosphate of water..(3 HO, PO5). Tribasic phosphate of water and soda..(NaO, 2 HO, PO5). Tribasic phosphate of soda and water..(2 NaO, HO, PO5). Tribasic phosphate of soda..(3 NaO, PO5). 1849D. Campbell Inorg. Chem. 317 Salts which are isomorphous with the salts of tribasic phosphoric acid. 1862Miller Elem. Chem. (ed. 2) III. 255 The..synthetic experiments of Berthelot..have shown that the ordinary varieties of natural fats and oils, are the tribasic ethers of the triatomic alcohol glycerin. 1875Ure's Dict. Arts (ed. 7) III. 863 Phosphates of Soda... The principal are the normal tribasic phosphate, the well-known rhombic phosphate [etc.]. 1899J. Cagney Jaksch's Clin. Diagn. vii. (ed. 4) 378 Being a tribasic acid, it forms three classes of salts—acid, neutral, and basic.
†2. Of an element: = triatomic b. Obs.
1862Miller Elem. Chem. (ed. 2) III. 52 Triatomic or Tribasic elements, each atom of which is in combination equivalent to H3 or three atoms of hydrogen. 1880E. Cleminshaw Wurtz' Atom. The. 204 Nitrogen has been represented as a tribasic element derived from the type of three condensed molecules of hydrogen. |