Question

# Which of the following solids is the structure of $CsCl$ crystal?A. Body-centered cubicB. Simple cubicC. Face centered cubicD. Edge centered cubic

Hint: We must know about crystal structure. We can define crystal structure as the ordered arrangement of atoms, ions, or molecules in a crystalline material. Therefore, $CsCl$ has a specific crystal structure. $CsCl$ consists of $Cs$ being at centre and surrounded by 8 atoms of $Cl$

Let’s start with discussing the options that are given to us for a better understanding.
The first one is body-centred cubic, the body-centred cubic consists of body centred unit cell. In these, there are eight atoms at each corner of the cube and each atom is shared by 8 unit cells and one central atom is there.
The second one is simple cubic, the simple cubic consists of a simple cubic unit cell in which there are only eight atoms at each corner of the cube and each atom is shared by 8 other unit cells.
The third one is Face centred cubic which consists of a face-centred unit cell in these 8 atoms are at the corners of the cube and each atom is shared by 8 other unit cells and one atom each at the faces and each atom is shared by 2 unit cell so a total of 6 atoms.
The last one is Edge centred cubic which consists of Edge centred unit cells. In these there are atoms which are shared by 4 other unit cells.

In case of $CsCl$, the Cs stays at the centre and is surrounded by 8 Cl atoms which form Body centred cubic structure.

So, the answer to this question is A. Body centred cubic structure.

Note:
These structures tell not only about how these atoms are being placed but also about how compact the structure is, how many void spaces are there or how much percentage of the structure is being covered by the atoms and how much is empty. These structures tell the characteristic of the molecule as how the molecule will react or which category it belongs to.