Explain the following 1) body centred cubic 2) face centred cubic
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- Body Centred Cubic
- there is one atom or ion in centre of the unit cell in addition to the corner atoms or ions.
- Face Centered Cubic
- there are atom or ion present on the six faces of the unit cell.
I hope this helps you to get a basic idea.
Body centered cubic (BCC) - A body centred cubic unit cell has an atom at each of its corner and also one atom at it's body centre.
Face centred cubic ( FCC) - A face centred cubic unit cell contains atom at all the corners and at the centre of all the faces of the cube. Each atom located at the face Centre is shared between two adjacent unit cells and only half of each atom belongs to a unit cell. It's also called cubic closest packing because it's packing fraction is highest ( 74% ).
1. Body centred cubic: It is the name given to a type of atom arrangement found in nature. A body-centred cubic unit cell structure consists of atoms arranged in a cube where each corner of the cube shares an atom and with one atom positioned at the center.
The atom at the corners of the cube are shared with eight other unit cells. As such, each corner atom represents one-eighth of an atom. Therefore, the BCC structure is said to have a coordination number of 8.
The center of the unit cell consists of 1 full atom, therefore the total number of atoms in the BCC unit cell structure is 2; one at the center plus eight one-eighth atoms at the corners.
1 atom + (1/8 atoms x 8 corners) = 2 atoms
2. Face Centred Cubic: An arrangement of atoms in crystals in which the atomic centers are disposed in space in such a way that one atom is located at each of the corners of the cube and one at the center of each face. This structure also contains the same particles in the centers of the six faces of the unit cell, for a total of 14 identical lattice points.The face-centred cubic unit cell is the simplest repeating unit in a cubic closest packed structure.
