Digallium III Tetrasulfide

A reaction tube is prepared as indicated in Fig. 2. The volume of the ampule D is determined, and the all-silica tube is thoroughly cleaned and dried before use. Before a seal is made at A, a small capsule C containing the correct amount of iodine is prepared and placed in the side chamber along with a steel bar B. For a reaction ampule D of volume 25 ml., the amount of iodine taken (5 mg./ml.) is 125 mg. (0.00049 mole). The iodine is contained in a thin-walled Pyrex tube under vacuum. Finally, a seal is made at A to close off the side chamber. 

Cadmium sulfidet (1.226 g., 0.0085 mole) and gallium(III) sulfide (2.000 g., 0.0085 mole) are mixed thoroughly in an agate mortar. The powdered mixture is transferred to the reaction 

The ternary sulfide, CdGa2S4, forms pale yellow tetragonal crystals with a = 5.56 A. and c = 10.1 A. Single-crystal x-ray analysis is in agreement with the reported unit-cell dimensions. The light yellow color of the crystals is probably due to the presence of a small amount of iodine. The crystals are piezoelectric. The crystalline compound is stable toward air and water at room temperature. 

Schafer, Chemical Transport Reactions, Academic Press Inc., New York, 1961. 

Submitted by ROBERT KERSHAW and AARON WOLD Checked by NORIO TASHIMAf and EPHRAIM BANKSf 

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