Iron occurs as BCC as well as FCC unit cell. If the effective radius of an atom of iron is 124 pm, compute the density of iron in both these structures.

Explanation

To compute the density of iron in both BCC (Body-Centered Cubic) and FCC (Face-Centered Cubic) structures, we can follow these steps:

### Step 1: Calculate the Edge Length for BCC Structure
The relationship between the edge length (a) and the atomic radius (r) in a BCC lattice is given by:
\[ a = \frac{4r}{\sqrt{3}} \]

Given that the effective radius of an atom of iron is \( r = 124 \, \text{pm} = 124 \times 10^{-12} \, \text{m} \), we can substitute this value into the equation.

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