Reciprocal lattice.
A device for tabulating both the slopes & the interplanar spacings of the Planes of a crystal lattice is provided by the concept of reciprocal lattice. General procedure for locating reciprocal lattice points:- → A lattice point is taken as common origin. → From the common origin, draw a normal to each plane. → Place a point on the normal to each plane (h k l) at a distance from the origin equal to 1/d(h k l). → Such points form a periodic array called reciprocal lattice.