Question

Find the simplest formula of a solid containing `A` and `B` atoms ia cubic arrangement In which `A` occuples corner and `B` the centre of the faces of unit cell. If the side length is `5 Å`, estimate the density of the solid assuming atomic weights of `A` and `B` as `60` and `90`, respectively.

Answer 1

Simplest formula `AB_(3), Mw = 60 + 3 xx90 = 330`
Volume of unit cell `= (5 xx 10^(-8))^(3) = 125 xx 10^(-24) mL`
One cell has one `AB_(3)`, molecule
So volume of one mole `= 125 xx 10^(-24) xx 6.023 xx 10^(23)`
`= 75.287 mL`
Density `= (330)/(75.287) = 4.38g cm^(-3)`