Niobium crystallises in body centred cubic structure. If the atomic radius is 143.1 pm, calculate the density of the element. (Atomic mass = 93 u)

Explanation

To calculate the density of niobium (Nb) which crystallizes in a body-centered cubic (BCC) structure, we will follow these steps:

### Step 1: Understand the BCC Structure
In a body-centered cubic structure, there are 2 atoms per unit cell (Z = 2).

### Step 2: Use the Relation Between Atomic Radius and Edge Length
The relationship between the atomic radius (r) and the edge length (a) for a BCC structure is given by:
\[ \sqrt{3}a = 4r \]
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