Ternary Alloys and Compounds

Examples of known ternary (and quaternary) chalcogenide compounds, classified according to a formal valence combination scheme, are given in Table 1.4. These compounds were collected from a compilation of Madelung [40] regarding semiconductor materials. To be sure, numerous other systems exist. Some important ternary compounds or classes will be considered in the relevant sections of the present chapter. 

Solid solutions are very common among structurally related compounds. Just as metallic elements of similar structure and atomic properties form alloys, certain chemical compounds can be combined to produce derivative solid solutions, which may permit realization of properties not found in either of the precursors. The combinations of binary compounds with common anion or common cation element, such as the isovalent alloys of IV-VI, III-V, II-VI, or I-VII members, are of considerable scientific and technological interest as their solid-state properties (e.g., electric and optical such as type of conductivity, current carrier density, band gap) modulate regularly over a wide range through variations in composition. A general descriptive scheme for such alloys is as follows [41]. 

Consider the ternary system having some range of mutual solid solu- 

Zn2ln2Ss, Zn3ln2Se, Hg5Ga2Teg, Hg3ln2Te6 (ordered vacancy compounds) Hg3PS3, Hg3PS4 

Cu2ZnSiS4, Cu2ZnSiSc4, Cu2ZnGeS4, Cu2ZnGeSc4 (44 compounds of the type) 

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