# DoITPoMS

Introduction

X-radiation ("X-rays") is electromagnetic radiation with wavelengths between roughly 0.1Å and 100Å, typically similar to the interatomic distances in a crystal. This is convenient as it allows crystal structures to diffract X-rays.

X-ray diffraction is an important tool used to identify phases by comparison with data from known structures, quantify changes in the cell parameters, orientation, crystallite size and other structural parameters. It is also used to determine the (crystallographic) structure (i.e. cell parameters, space group and atomic coordinates) of novel or unknown crystalline materials.

In crystallography, measurements are expressed in Ångströms (Å). An Ångström corresponds to 1 x 10-10 m; so one Ångström is equal to 0.1 nm.