Give the number of lattice points in one unit cell of the crystal structure. i) Simple cubic ii) Face centered cubic iii) Body centered cubic iv) Face centered tetragonal
Answers
Answer:
(i) Face–centred cubic:-
A face–centred cubic (fcc) unit cell contains atoms at all the corners and at the centre of all the faces of the cube.
FACE CENTERED CUBIC
So lattice point at the corner = 8
Lattice point at the center of all faces = 6
Total number of lattice point = 14
(ii) Face–centred tetragonal
lattice point at the corner = 8
Lattice point at the center of all faces = 6
Total number of lattice point = 14
(iii) Body–centred
In Body centered cubic there are 8 lattice point at the corner and 1 is at the center so total 8+1 =9 lattice point
Answer:
Lattice points in one unit cell represent the positions of atoms, ions or molecules in the unit cell.
(1) Simple cubic unit cell: In this primitive unit cell, the lattice points are at 8 corners of the unit cell. Hence there are 8 lattice points.
(2) Face-centred cubic unit cell: In this unit cell, the attice points are at 8 corners and 6 face centres. (In cubic close packing unit cell, the lattice points are also at edge centlres and body centre.)
(3) Body-centred cubic unit cell: In this, the lattice points are at 8 corners and one at body centre.