Question

A unit of $BaC{l}_2$ (fluorite structure) is made up of:

• A. four $B{a}^{2+}$ ions and four $C{l}^{-}$ ions
• B. four $B{a}^{2+}$ ions and eight $C{l}^{-}$ ions
• C. eight $B{a}^{2+}$ ions and four $C{l}^{-}$ ions
• D. four $B{a}^{2+}$ ions and six $C{l}^{-}$ ions

Answer 1

Answer: (C)

eight $B{a}^{2+}$ ions and four $C{l}^{-}$ ions

${BaCl}_2$ has ${CaF}_2$ type structure. In ${BaCl}_2$,

• The ${Ba}^{2+}$ ions form the ccp arrangement, i.e., these ions occupy all the corner positions and the center of each face of the cube.

The coordination of the compound is 8:4.

In a unit of $BaC{l}_2$, there are eight $B{a}^{2+}$ ions and four $C{l}^{-}$ ions.

So, option C is correct.