Calculation of d -spacing and lattice parameters:

The various sets of planes in a lattice have different values of inter-planar spacing. The planes of larger spacing have low indices and pass through a high density of lattice points.

The inter-planar spacing d_hkl measured at right angles to the planes is a function of both the plane indices (hkl) and the lattice constants (a,b,c, α, β, γ), as shown in Figure 4.04.

Figure 4.04: Schematic of a cube with different planes and angles.

The exact relation depends on the crystal system involved. The value of d can be calculated using Bragg's law