Solid State and Crystal Structures

Palladium (Pd) and silver (Ag) crystallise in face centred cubic lattice.

Tantalum (Ta) and tungsten (W) crystallises to form body centred cubic lattice.

The space group (or crystallographic group, or fedorov group) of a crystal is a description of the symmetry of the crystal, and can be one of 230 types.

In the hexagonal system, we have an additional axes which gives the crystals six sides. Three of these are equal in length and meet at 60° to each other. The C or vertical axis is at 90° to the shorter axes. Mineralogists sometimes divide this into two systems, the hexagonal and the trigonal, based on their external appearance.

Point defects are defects that occur only at or around a single lattice point. They are not extended in space in any dimension. Strict limits for how small a point defect is, are generally not defined explicitly, but typically these defects involve at most a few extra or missing atoms.

The trigonal crystal system is one of the seven crystal systems. It consists of the five point groups of the seven space groups with a rhombohedral lattice. In the classification into 6 crystal families, the trigonal crystal system is combined with the hexagonal crystal system and grouped into a larger hexagonal family.

In crystallography, the space group of a crystal is a description of the symmetry of the crystal and can have one of 230 types.

Orthorhombic crystal system: Unit cell vector lengths a≠ b ≠ c and unit cell vector angles α = β = γ = 90° Tetragonal crystal system: Unit cell vector lengths a = b ≠ c and unit cell vector angles α = β = γ = 90°

For orthorhombic lattice system, possible Bravais lattices are primitive, body centered, face centered and base centered.

This option is correct because 'lattice system: edge lengths and axial angles in Monoclinic is a ≠ b ≠ c and α = γ = 90˚, β ≠ 90˚ respectively. in Triclinic, the 'lattice system: edge lengths and axial angles is a ≠ b ≠ c and α ≠ β ≠ γ ≠ 90˚

Wurtzite structure of ZnS is related to hcp structure, whereas zinc blende structure of ZnS is related to ccp structure.

In cesium chloride (CsCl) crystal lattice, coordination number of both cation (Cs⁺) as well as anion (Cl^-) is 8.

For rhombohedral lattice system the only possible Bravais lattices is primitive type.

The crystal structure of CsCl is simple cube.

The number of atoms per unit cell in a bcc crystal is 2.