the cordination number ofcation and anion in fluoriteCaF2 and CsCl are respectively

Coordination number in CaF2 = 8:4

In fluorite, calcium ion is present at the corners and at the face of the lattice where as Fluoride ions are present at the tetrahedral voids

Each F^- ion in this structure is surrounded by 4 Ca²⁺ ions whereas each Ca²⁺ ions is surrounded by eight F^- ions which are present at the corners of a cube. The coordination of the compound is 8:4 as shown in the figure



Coordination number in CsCl is = 8:8

In CsCl lattice all the Cs ions are present at the corners where as all Cl ions are present at the body centre. Thus each Cl ion ion is surrounded by 8 Cs ion present at the corner, and each Cs ion is surrounded by 8 Cl ion present at the body centre of lattice as shown in the figure