Iron crystallizes in a body-centered cubic lattice.If the radius of iron is 126 pm,what is the unit cell edge length?
A) 291 pm
B) 252 pm
C) 168 pm
D) 126 pm
E) 54.6 pm

Question

Quizplus · Accepted Answer

In a body-centered cubic (bcc) lattice, the diagonal across the cube is equal to 4 times the radius of the atom (4r). The diagonal can also be expressed in terms of the edge length (a) as √3a. Setting these equal and solving for a gives a = 4r/√3. Substituting the given radius of iron (126 pm) into this formula yields an edge length of approximately 291 pm.

Iron Crystallizes in a Body-Centered Cubic Lattice