Question

An ionic solid feo crystallises into a cubic structure and has a edge length equal to 5a

Answer 1

Answer & Explanation:

FeO has a NaCl like crystal lattice structure where the cation prefer the octahedral sites and the overall structure of crystal lattice is of FCC.

FCC stands for face centered cubic structure, which means there is a anion at the face of every cube of crystal lattice while the cation is on the opposite corner.

Hence, the calculation goes like this,

edge² + edge² = (4 x radius of atom(r))²

2 edge² = (4 x r)²

√2 edge = 4 x r

r = edge /  2√2

Therefore, radius of atom = 5a/2√2.