| 释义 |
hexad|ˈhɛksæd|
[ad. Gr. ἑξάς, -αδ- a group of six, f. ἕξ six.]
1. The number six (in the Pythagorean System); a series of six numbers.
1660Stanley Hist. Philos. ix. x. (1687) 528/1 The Pythagoreans held the number Six to be perfect..The names of the Hexad are these.
2. A group of six.
1879G. Salmon Higher Plane Curves vi. (ed. 3) 234 The following two groups of hexads of bitangents. Ibid., These 1008 and 5040 hexads have been studied by Hesse as bitangents whose twelve points of contact lie on a proper cubic.
3. Chem. An element or radical that has the combining power of six units, i.e. of six atoms of hydrogen. Chiefly attrib. or adj.
1869Roscoe Elem. Chem. 187 Six molecules of water in which half of the hydrogen is replaced by a hexad group. 1877W. A. Miller's Elem. Chem. i. (ed. 5) 34 Hexads or Elements, each atom of which in combining may represent six atoms of Hydrogen.
Hence heˈxadic a., of the nature of a hexad (sense 3).
1873Fownes' Chem. (ed. 11) 251 Sulphur has..lately been shown to form certain organic compounds in which it is tetradic, and others in which it appears to be hexadic. |