XYZ file format

The XYZ file format is a chemical file format. There is no formal standard and several variations exist, but a typical XYZ format specifies the molecule geometry by giving the number of atoms with Cartesian coordinates that will be read on the first line, a comment on the second, and the lines of atomic coordinates in the following lines. The file format is used in computational chemistry programs for importing and exporting geometries. The units are generally in ångströms. Some variations include using atomic numbers instead of atomic symbols, or skipping the comment line. Files using the XYZ format conventionally have the .xyz extension.