A compound consisting of the monvalent ions,A^(+) , B^(-)crystallizes in the body -centred cubic lattice. (i) What is the formula of the compound ?(ii)If one ofA^(+)ions from the corner is replaced by a monovalent ion C^(+). What would be the simplest formula of the resulting compound ?

A compound consisting of the monvalent ions,A^(+) , B^(-)crystallizes

1.	A compound consisting of the monvalent ions,A^(+) , B^(-)crystallizes in the body -centred cubic lattice. (i) What is the formula of the compound ?(ii)If one ofA^(+)ions from the corner is replaced by a monovalent ion C^(+). What would be the simplest formula of the resulting compound ?
Answer» SOLUTION :(i) Contribution of ` A^(+)`ions present at the corners to WARDS unit cell=` 8 XX 1/8 =1` Contribution of `B^(-)`ION present at the body - centre =1 Ration of ` A^(+) : B^(-)`= 1:1 . Hence , the formula is AB. (ii)` A^(+)` ions at the corners = 7. Hence, their contribution towards unit cell = ` 7/8` ` C^(+)` ion at one corner contributes = `1/8` ` B^(-)` ion at the body centre has contribution =1 . Hence, ratio of A:B :C =` 7/8 : 1/8 :1 = 7: 1 : 8` Formula will be ` A_(7)BC_(8)`