Which one of the following pairs is not correctly matched?Space Lattic...
Ans is C
for SC structure a=2r
for BCC √3a = 4r
for FCC. √2a = 4r
for triclinic lattice parameters a,b,c have different values.
Which one of the following pairs is not correctly matched?Space Lattic...
Explanation:
The relation between the atomic radius (r) and edge length (a) for different crystal structures can be derived using the concept of space lattice.
Simple Cubic Structure:
In a simple cubic structure, each atom is located at the corners of the cube. The coordination number is 6 and the edge length is denoted by 'a'. The relation between the atomic radius and edge length is given by:
a^2 = 4r^2
Body-Centred Cubic Structure:
In a body-centred cubic structure, each atom is located at the corners of the cube and one atom is present at the body centre of the cube. The coordination number is 8 and the edge length is denoted by 'a'. The relation between the atomic radius and edge length is given by:
3a^2 = 16r^2
Triclinic Structure:
A triclinic crystal structure is the most general type of crystal structure and does not have any specific relation between the atomic radius and edge length. Therefore, the given relation 2a^2 = 3r^2 for a triclinic structure is not correctly matched.
Face-Centred Cubic Structure:
In a face-centred cubic structure, each atom is located at the corners and face centres of the cube. The coordination number is 12 and the edge length is denoted by 'a'. The relation between the atomic radius and edge length is given by:
a^2 = 8r^2
Conclusion:
The given relation for the triclinic structure, 2a^2 = 3r^2, is not correctly matched. The correct relation for the triclinic structure is not specified as it can have various values depending on the crystal lattice parameters.