Iron oxide (feo) has the rock salt crystal structure and a density of 5.70 g/cm3. the atomic weights of iron and oxygen are 55.85 g/mol and 16.00 g/mol, respectively. (a) determine the unit cell edge length

The unit cell edge length is  

Explanation:

NaCl has FCC structure. and so is the FeO.

Number of atom in unit cell of FCC (Z) = 4

Density of FeO=

Edge length = a

Atomic mass of FeO(M) = 55.85 g/mol +16.00 g/mol = 71.85 g/mol

Formula used :  

where,

= density

Z = number of atom in unit cell

M = atomic mass

= Avogadro's number  

a = edge length of unit cell

On substituting all the given values , we will get the value of 'a'.

The unit cell edge length is