X-ray diffraction and interplanar spacings

Bragg's law allows us to calculate interplanar spacings that satisfy the constructive interference condition. Therefore, these are peaks we will see in XRD or X-ray diffraction when we scan samples and monitor intensity as a function of two theta diffraction angle. We need to relate these peaks to specific hkl planes and we can do this using Bragg's law in conjunction with a calculation of interplanar spacing based on the crystal structure and known h k l miller indices.