The energy of the vacancy formation in the Ge crystal is about 2.0 eV/atom. Calculate the fractional concentration of vacancies in Ge at 940 0C, just below its melting temperature, given that the atomic weight and density of Ge are 73 g/mol and 5.32 g/cm3, respectively?

6. A compound consists of A-atoms and B-atoms, and its solid crystal forms a cubic unit cell structure, as shown below. A-atoms occupy corners and faces of the cube. B-atoms are inside the cube and are not shared by adjacent cubic unit cells. Based on the information here, we can conclude that (a) A-atoms form an FCC structure; the empirical formula of the compound is A,B2. (b) A-atoms form an FCC structure; the empirical formula of the compound is AB. (c) A-atoms form a BCC structure; the empirical formula of the compound is A¬B2. (d) A-atoms form a BCC structure; the empirical formula of the compound is AB. (e) None of the above. A-atoms (corners and faces) B-atoms (inside, not shared) a m n T OF THE FL EMENTS

In a simple cubic lattice (based on a single element) with atoms at each point in the lattice and with a lattice constant a, what is the density of atoms (number per unit area) on a surface (100) .