for NaTl, is the unit cell of it based on the repetition of body centered cubic and the holes in this unit cell are octahedral?
how many of each of the 2 cubes drawn for NaTl are required its unit cell? is it 8?
Yes, the unit cell of NaTl is based on the repetition of the body-centered cubic (BCC) structure. In this unit cell, the holes present are octahedral voids.
Regarding the number of cubes in the unit cell, for a BCC structure, there is 1 full cube at the center of the unit cell. Additionally, there are 8 smaller cubes at each of the 8 corners of the unit cell. Therefore, a total of 9 cubes are required to form the unit cell of NaTl, not just 8.
To determine the unit cell structure and the number of cubes required for NaTl, we need to understand its crystal structure. NaTl refers to sodium thallide, which is an ionic compound.
The crystal structure of NaTl is based on the repetition of the body-centered cubic (BCC) unit cell. In a BCC unit cell, there is one central atom at the center of the cube and eight atoms at the vertices.
However, in the case of NaTl, the BCC unit cell is modified by replacing each of the eight corner atoms with ions having a coordination number of 4, forming tetrahedral holes. Additionally, there is one ion at the center of each face of the unit cell, forming octahedral holes.
So, in the unit cell of NaTl, there are eight tetrahedral holes and six octahedral holes.
Now, to address your question about the number of cubes drawn, it seems there might be some confusion. The unit cell of NaTl consists of only one cube. This cube represents the repeating pattern of atoms or ions within the crystal lattice. So, there is no need to draw multiple cubes to represent the unit cell.
To summarize, the unit cell of NaTl is based on the repetition of the body-centered cubic (BCC) structure, with eight tetrahedral holes and six octahedral holes. And there is only one cube representing the unit cell.