Lec 12b Symmetry, Structure, Tensor Properties of Materials
PROFESSOR: Since z, that's straight up. And that is going to provide for you a cell that has the shape of a square prism. This would be a1. This would be a2. And this would be a3-- I'm sorry, this would be c. And if you took the choice for the third translation as 1/2 half of a1 plus 1/2 of a2 plus some amount z up above the base of the cell, and then redefined a T3 prime that would be equal to-- sorry. What am I doing here? Yeah. This is right. 1/2 of a1 1/2 of a2, and z straight up. Define a T3 prime as 2T3 minus a1 minus a2. And that will define for you, again, a cell in the shape of a square prism with a1 and a2. And now the translation that went up directly over the center of the base of the net below. Twice that minus a2 minus a1 brings you back to a third translation T3 prime that's normal to the base. So both cells have the same shape. This is a primitive. This is a body-centered tetragonal lattice. And the symbol that's used to represent the body-...