The hcp and ccp structure of a given element. (Given radius of element is same in both structures)

Question

TestHub · Accepted Answer

Question Explanation:

The question asks about the correct properties for hexagonal close-packed (hcp) and cubic close-packed (ccp) structures.

Concept:

This question is based on hcp and ccp structures.

Solution:

(3) Coordination Number (C.N.) in HCP = FCC = 12.

(4) Unoccupied space = 26% = HCP = FCC

(1) Density:

$d_{FCC - CCP} = \frac{4 \times M . M}{N _{A} \times a ^{3}}$

$= \frac{4 \times M . M}{N _{A} \times ( 2 2 r ) ^{3}}$

$\frac{1}{4 2 r ^{3}} \times \frac{M . M}{N _{A}}$

Packing fraction:

$P_{H CP} = \frac{6 \times M . M}{N _{A} \times 24 2 r ^{3}} (v o l m p o f H CP = 242 r^{3})$

$\frac{1}{4 2 r ^{3}} \times \frac{M . M}{N _{A}}$

(Given: the radius of the element is the same in both structures)

(2)

hcp and ccp have same distance between two consecutive layers

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