Looking at Figure 12.27 identify the coordination numbers of the Cu, Y, and Ba atoms.

Video transcript

Hello. In this problem we are asked to identify the coordination numbers of the blue atoms, the red atoms and the yellow atoms in the following crystal structure. So we can find coordination number which I'll write shorthand is C. N. If we count up the number of atoms bonded to an atom in the unit cell. So let's begin with the red Adams. So the red atoms, then we'll start with the one on top is bound to the two green atoms and the plane above it, the four green atoms on the same plane and four atoms on the plain below the red atom. So that's a total of 10 coordination numbers 10. Let's now look at the red atom on the bottom. It has it is bound to the four green on the plane above it. For green atoms on the same plane And two boy. So again that's a total of 10. But now look at the yellow atom in the center of this crystal structure. The yellow atom is bound to four blue atoms on the plane above it And four blue atoms on the plain below it. So the coordination number is eight. And to determine the coordination number for the blue atoms, we're going to need to draw an extension of the unit cell. So extending the unit cell then the top blue atom where we've extended the unit cell, it is bound to before green atoms that form the square planer shape. And then if we look at the blue atom beneath it, it is bound to These five green atoms that form this square pyramidal shape. So the blue atoms Have a coordination number of four if you saw on the extension at the top of the crystal structure, and they also have a coordination number of five. So we can determine the coordination number the atoms in the crystal structure. If we again count up the number of random that are bound to it. In this case, red Adams had 10, the L adam had eight, and the blue Adams had four and five. Thanks for watching. Hope. This helps.