CCP stands for cubic closed packing , FCC is for face centered cubic structure and HCP is for hexagonal cubic packing . Both the structures have a packing effeciency of 74% . Now sometimes we also call it as face centered closed structure (FCC)But remember FCC can also stand for the unit cell (Face centered cell).

Similarly, it is asked, why FCC is also called CCP?

CCP is the cubic closed packing,FCC is for face entered cubic structures. When we place the atoms in the octahedral voidsthe packing is of ABCABC type hence its known as CCP while FCC stands for the unit cell.

Beside above, what is the coordination number in CCP arrangement? 12

Secondly, what is the difference between CCP and HCP?

There are few types of close packed crystal structures such as HCP (Hexagonal closest packed) and CCP (Cubic closest packed). The key difference between HCP and CCP is that the repeating structure of HCP has 2 layers of spheres whereas the repeating structure of CCP has 3 layers of spheres.

Is FCC close packed?

There are two simple regular lattices that achieve this highest average density. They are called face-centered cubic (fcc) (also called cubic close packed) and hexagonal closepacked (hcp), based on their symmetry.

Related Question Answers

What is fcc and bcc?

The face-centered cubic (fcc) has a coordination number of 12 and contains 4 atoms per unit cell. The body-centered cubic (bcc) has a coordination number of 8 and contains 2 atoms per unit cell. The simple cubic has a coordination number of 6 and contains 1 atom per unit cell.

What is CCP FCC?

CCP stands for cubic closed packing , FCC is for face centered cubic structure and HCP is for hexagonal cubic packing . Now , HCP and CCP are one of the forms in which a cubic lattice is arranged and FCC is one of the types of unit cells(in general)

How many octahedral voids are in CCP?

4 octahedral voids

What is fcc structure?

arrangement of atoms

, which is called the face-centred cubic (fcc), or cubic-closest-packed, lattice. Copper, silver (Ag), and gold (Au) crystallize in fcc lattices. In the hcp and the fcc structures the spheres fill 74 percent of the volume, which represents the closest possible packing of spheres.

Why is BCC not close packed?

The bcc structure simply does not contain planes with this packing. The most densely packed planes are {110}, which looks like this: Image source. You'll see that the packing does not have hexagonal symmetry, and that the atoms are not packed as closely as possible.

How many tetrahedral voids are there in CCP?

The answer to the first question is that the number of tetrahedral voids per atom is two and the number of octahedral voids per atom is one. These are the same as those for Cubic Close-Packed (CCP) structure. To answer the 2nd question we should note that the primitive unit cell of the HCP structure contains two atoms.

What is hcp structure?

Hexagonal close packed (hcp) refers to layers of spheres packed so that spheres in alternating layers overlie one another. Hexagonal close packed is a slip system, which is close-packed structure. The hcp structure is very common for elemental metals, including: Beryllium.

Why does the FCC have coordination number 12?

Face Centered Cubic (FCC) Structure

Each of the corner atoms is the corner of another cube so the corner atoms are shared among eight unit cells. Additionally, each of its six face centered atoms is shared with an adjacent atom. Since 12 of its atoms are shared, it is said to have a coordination number of 12.

How many octahedral voids are present in FCC?

four octahedral voids

What is the full form of HCP in chemistry?


In a hexagonal close-packed (hcp) arrangement of atoms, the unit cell consists of three layers of atoms. The top and bottom layers (a) contain six atoms at the corners of a hexagon and one atom at the center of each hexagon.

What is the coordination number for HCP CCP?

A CCP arrangement has a total of 4 spheres per unit cell and an HCP arrangement has 8 spheres per unit cell. However, both configurations have a coordination number of 12.

What is a close packed plane?

A close packed plane at the bottom and top of the unit cell is separated by 3 atoms in the cell center, which are also part of a closed packed plane.

How will you distinguish between tetrahedral and octahedral voids?

Tetrahedral void is a simple triangular void in a crystal and is surrounded by four spheres arranged tetrahedrally around it. On the other hand, an octahedral void is a double triangular void with one triangle vertex upwards and the other triangle vertex downwards and is surrounded by six spheres.

What is unit cell in solid state?

A unit cell is the most basic and least volume consuming repeating structure of any solid. It is used to visually simplify the crystalline patterns solids arrange themselves in. When the unit cell repeats itself, the network is called a lattice.

What is hexagonal close packing?

Hexagonal Close Packing. In hexagonal close packing, layers of spheres are packed so that spheres in alternating layers overlie one another. As in cubic close packing, each sphere is surrounded by 12 other spheres.

What is cubic close packing arrangement of spheres?

Cubic Close Packing. Simple cubic packing consists of placing spheres centered on integer coordinates in Cartesian space. Arranging layers of closepacked spheres such that the spheres of every third layer overlay one another gives face-centered cubic packing.

What is the edge length of hcp lattice?

Answer: For hcp lattice the edge length is equal to 4 atoms per unit and hexagonal closest packed is number of the 12 and it hold 6 atoms per units.

What are the 7 types of crystals?

There are seven main structures of crystals, depending on the shape of the crystal. These are cubic, hexagonal, tetragonal, orthorhombic, trigonal, monoclinic, and triclinic.

Is NaCl FCC or BCC?

General Notes. NaCl has a cubic unit cell. It is best thought of as a face-centered cubic array of anions with an interpenetrating fcc cation lattice (or vice-versa). The cell looks the same whether you start with anions or cations on the corners.