Question

What is the co-ordination number of hcp crystal lattice?

• A. 8
• B. 12
• C. 6
• D. 6

Answer 1

The Correct Option is B

The coordination number of a crystal lattice refers to the number of nearest neighboring atoms or ions surrounding a central atom or ion. 
In a hexagonal close-packed (hcp) crystal lattice, the coordination number is 12. Each atom in the hcp lattice is in contact with 12 nearest neighboring atoms. This is achieved through a hexagonal arrangement of layers, with each layer having six atoms and three layers stacked on top of each other. 
Therefore, the correct option is (B) 12.