The volume V of the unit cell in Figures:
V=Area of rhombus base xx Height (c)
`=(a^(2)sin60^(@))xxc=(4.53overset(@)A)^(2)(0.866)(7.41overset(@)A)`
`=132overst(@)A^(3)=132xx10^(-24)cm^(3)`
Mass of unit cell=V xx Density
`=(132xx10^(-24)cm^(3))(0.92gcm^(-3))(6.02xx10^(23))`
=73g
Number of moles of `H_(2)O=(73)/(18)=4`.