HCP And CCP Full Form
Introduction
Regarding crystal systems or lattice structures, the phrase "close-packed structure" is used. It defines atoms that are closely packed together in crystal formations. An atom in a crystal system is referred to as a "sphere". This is due to the fact that an atom is thought of having a spherical structure for the purposes of characterising crystal systems. Equal spheres packed closely together will create a thick crystal system with the fewest possible gaps or openings. Different kinds of holes can exist in the space between spheres. Trigonal holes, which resemble triangles when three equal spheres are arranged side by side, are those that exist between them. In this article, we will see more about both the types of closed packings that are HCP and CCP.
- Introduction
- Full Form of HCP and CCP
- More About HCP
- More About CCP
- Features That HCP and CCP Have in Common
- Difference Between HCP and CCP
Full Form of HCP and CCP
HCP stands for Hexagonal Closed Packing and CCP Cubic Close Packing are two examples of the few forms of close-packed crystal formations. The repeating structure of HCP contains 2 layers of spheres while the repeating structure of CCP has 3 layers of spheres, which is the main distinction between the two.
More About HCP
The third layer of spheres in hexagonal close-packed crystal systems has the same configuration as the first layer of spheres. The tetrahedral holes in the first layer and third layer are then covered by the spheres of the second layer.
Around 74% of the volume of the hexagonal close-packed crystal system is made up of spheres or atoms, while the remaining 26% is made up of empty spaces. In the Hexagonal close-packed structure, 12 spheres surround a single atom or sphere. Each unit cell in the Hexagonal close-packed crystal structure contains 6 members (atoms or spheres).
More About CCP
In CCP, the second layer of spheres is positioned over half of the first layer's depressions. The first and second layers are completely different from the third layer. The depressions of the second layer are filled with the third layer. Since the layers are not packed in a straight line, this packing fills in all of the octahedral holes. The structure, however, repeats since the fourth layer resembles the first layer.
Around 74% of the volume of the cubic closest packed crystal structure is made up of spheres or atoms, while the remaining 26% is made up of empty spaces. In the cubic close-packed structure, one atom or sphere is surrounded by 12 nearby spheres, just like in the Hexagonal close-packed structure.
Each unit cell in the Cubic closest packed crystal system contains 4 members (atoms or spheres).
Features That HCP and CCP Have in Common
There are 12 neighbouring spheres between the spheres in both HCP and CCP.
Around 74% of the volume of the HCP and CCP crystal systems is occupied by spheres or atoms, and 26% of the volume is made up of empty spaces.
Difference Between HCP and CCP
HCP | CCP |
Full form of HCP is Hexagonal close packing. | The full form of CCP is Cubic close packing. |
Six individuals make up an HCP unit cell. | Four individuals make up a CCP unit cell. |
The second layer of spheres in HCP crystal systems covers the first layer and the third layer's tetrahedral holes since the third layer's sphere arrangement is the same as that of the first layer. | In CCP crystal systems, the third layer is fundamentally different from the previous two levels, it is piled in the depressions of the second layer. The second layer of spheres is placed on top of half of the depressions of the first layer. |
Two layers of spheres make up the repeating structure of the HCP. | Three layers of spheres make up the repeating structure of the CCP. |
The "ABA" configuration is referred to as a hexagonal closure. | The cubic close packing (CCP) layout is also known as the "ABCA" arrangement. |
Tetrahedral and octahedral holes are seen in the hexagonal closest packing. | Tetrahedral holes can be found in cubic close packing, whereas octahedral holes are hidden by a spherical layer. |
The pattern in HCP is ABAB. | The pattern in CCP is ABCABC. |
Examples of the HCP include the packed lattice structure found in many metals, including zinc and magnesium, among others. | Examples of the CCP include Metals like copper and silver exhibit this kind of close packing of component particles. |
Frequently Asked Questions (FAQs)
The given elements HCP and CCP structure will have the same coordination number and the same packing fraction.
No, the initial two levels in both the HCP and CCP have exactly the same arrangements.
The arrangement of consecutive layers in CCP is designated as ABCABCABC.
The coordination number in HCP arrangement is 12.
The coordination number in the CCP arrangement is the same as in HCP arrangement which is 12.