Question

Given an alloy of Cu, Ag and Au in which Cu atoms constitute the CCP arrangement.If the hypothetical formula of the alloy is Cu4Ag­3Au. What are the probable locations of Ag and Au atoms.

• A. Ag - all Tetrahedral voids; Au - all Octahedral voids
• B. Ag - 3/8th Tetrahedral voids; Au - 1/4th Octahedral voids
• C. Ag - 1/2 Octahedral voids; Au - 1/2 Tetrahedral voids
• D. Ag - all Octahedral voids; Au - all tetrahedral voids

Answer 1

Answer: (B)

Ag - 3/8th Tetrahedral voids; Au - 1/4th Octahedral voids

Answer 2

Cu4 Ag3 Au

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Froms c.c.p. , $\frac{3}{8}$th of tetrahedral voids , $\frac{1}{4}$of Octahedral voids [\ No. of O- voids = 4]

z = 4, [\ No. of T- voids = 8].