Question

The ABAB packing and ABCABC packing are respectively called as:

• A. hexagonal close packing (hcp) and cubic close packing (ccp)
• B. cubic closed packing (ccp) and hexagonal closed packing (hcp)
• C. body centered cubic (bcc) and hexagonal close packing (hcp)
• D. hexagonal closed packing (hcp) and body-centered cubic (bcc)

Answer 1

The correct option is A hexagonal close packing (hcp) and cubic close packing (ccp)

$\text{Solution:- Packing of lattice points in a crystal is of 2-types:-}$

$\text{1.) Cubic dose packing (CCP)}$

$\text{2.) hexagonal close packing (HCP)}$

$\text{layers of packing sphere or lattice points}$

$\text{in ccp \& hcp are}3\text{.}$

$\text{- CCP is ABCABC ... type}$

$\text{and}$

$\text{- HCP is}AB△BAB\text{.... type.}$

$\text{Examples:-}$

$\text{- Zinc blende}\left(ZnS\right)(4:4)-ccp\text{.}$

$\text{- Wurtzite}\left(ZnS\right)(4:4)-hcp\text{.}$

$\text{hence correct option is (A)}$