Question

EENG 245 Physical electronics HW 1 1) The NaCl crystal is cubic, and can be described as follows. Na atoms sit at the corners and faces of a cube, and Cl atoms sit in between two Na atoms. This means that a Clatom is found half-way along each of the cube edges, and there is a Cl in the center of the cube. (We could also have described the lattice by interchanging Na and Cl in the description above.) Another way to describe the lattice is to say that it consists of Na and Cl both arranged in an fcc lattice, but displaced from one another by a distance a/2 along one of the axes x, y, or Z. Still another was to describe it is to say that a Na atom is surrounded by 6 nearest-neighbor Cl atoms, and vice-versa, in a cubic structure. a) Make a sketch of the NaCl lattice. b) Find the lattice constant of NaCl. To do this, assume that Na and Cl atoms are touching each other in positions as described above. Now, if you know the atomic radii of the atoms, you can find the distance across the lattice. (Atomic radii are available on the web site indicated above.) c) Given the lattice constant, find the density of NaCl. (You should get approximately 2.21 g/cm3.)

Answer 1

e-4 [22:9897 + 35: 453] x 166 1 X 1024 atemi 18.6 x 108] = 2-211036 g I can a 2-21 glam