Cuprous iodide, Cu 2 l 21 is obtained as a white powder, which suffers little alteration on exposure, by the direct union of its components or by mixing solutions of cuprous chloride in hydrochloric acid and potassium iodide; or, with liberation of iodine, by adding potassium iodide to a cupric salt.
The most important are cuprous oxide, Cu 2 0, and cupric oxide, CuO, both of Oxides which give rise to well-defined series of salts.
A phosphide, Cu 3 P 2, is formed by passing phosphoretted hydrogen over heated cuprous chloride.
Of these we may mention whitneyite, Cu 9 As, algodonite, Cu 6 As, and domeykite, Cu3As.
Cuprous oxide, Cu 2 0, occurs in nature as the mineral cuprite (q.v.).
They have also formed in this way certain alloys of definite composition, such as AuCd 3, Cu 2 Cd, and, more interesting still, Cu 3 Sn.
It melts at below red heat to a brown mass, and its vapour density at both red and white heat corresponds to the formula Cu 2 C1 2.
Cu2S5, Cu 2 S 6, Cu4S5, Cu 2 S 3, have been described; they are all unstable, decomposing into cupric sulphide and sulphur.
In the vowel-system a notable feature is the presence th the short vowels e and o, which are not found in Sanskrit and cu d Persian; thus the Sanskrit sanhi, Old Persian hantiy, becomes un, 11i in Zend.
Cupric iodide is only known in combination, as in Cu12, 4NH 31 H 2 O, which is obtained by exposing Cu 2 I 2, 4NH 3 to moist air.