Standard X-ray Diffraction Powder Patterns

Gallium Arsenide, GaAs (cubic)Powder data cards. None.Additional published patterns. Is one.NBS sample. The sample of gallium arsenidewas obtained from Semitronics Inc., Winchester,Mass. Spectrographic analysis showed the following major impurities: 0.1 to 1.0 percent iron,0.01 to 0.1 percent chromium, nickel, and lead;and 0.001 to 0.01 percent each of cobalt, copper,indium, manganese, molybdenum, and silicon.The sample was a dark gray opaque powder.The ^-values of the three strongest lines are:3.262, 1.998, and 1.704 A.Structural data. Goldschmidt [1] in 1927 determined that gallium arsenide has the zinc sulfidestructure, the space group Td-F43m (No. 216),and 4(GaAs) per unit cell.Lattice constanthkl111220311400331422511440531620533444711dA3. 2621.9981.7041.4131. 2971. 1541.0880. 9993.9557.8938.8621. 8159.7916Internal Standard,Tungsten, a = 3.1648 ACu, 1.5405 A at 25 °C/1006129711175366426aA5. 6485.6505. 6505.6485. 6525.6475.6485.6525.6535.6525.6525.6525.6521963 National Bureau of Standards at25 °CL______--_____ ________A5. 652Average value of last five lines____--5.652ReferenceThe density of gallium arsenide calculated fromthe NBS lattice constant is 5.321 g/cm3 at 25 °C.[1] V. M. Goldschmidt, Geochemische VerteilungsgesetzeVIII, Skrifter Norske Vidensk, Akad. Oslo, Math.Nat. Kl. 8, 390 (1926-27).33