Introduction:
The CsCl (cesium chloride) structure is a simple cubic structure that consists of two interpenetrating simple cubic lattices, one of cesium ions and the other of chloride ions.

Edge Length:
If the edge length of the CsCl structure is "x", then the distance between one Cs (cesium) atom and one Cl (chloride) atom is equal to the body diagonal of a cube with an edge length of "x".

Explanation:
To understand this, we need to consider the geometry of the CsCl structure. The cesium ions and chloride ions occupy alternate corners of a cube, and each ion is surrounded by 8 ions of the opposite kind.

The distance between two ions in the CsCl structure can be calculated using the Pythagorean theorem, which states that the square of the length of the diagonal of a cube is equal to the sum of the squares of its edges.

In the case of the CsCl structure, the body diagonal of the cube (which passes through the center of the cube) is equal to the square root of 3 times the edge length of the cube. Therefore, the distance between one Cs atom and one Cl atom in the CsCl structure is equal to the square root of 3 times the edge length of the cube.

Conclusion:
In summary, if the edge length of the CsCl structure is "x", then the distance between one Cs atom and one Cl atom is equal to the square root of 3 times "x". This distance is important in determining the properties of the CsCl structure, such as its melting point, lattice energy, and other physical and chemical properties.

D=√3/2*x