XYZ file format is used for storing data describing chemical molecule in form of a plain text file. XYZ files don’t follow strict format standard specification; first row usually contains information about number of atoms, second row contains comments and third row contains list of atoms including atomic symbol and coordinates in Carthesian coordinate system.

XYZ files are used by chemistry software such as Jmol, TINKER, UniChem or VMD. They can serve as means of importing and exporting geometrical data of molcules, as well as supply data for simulations. XYZ is sometimes used for demostration purposes as a generic extension format, or in situation when file extension is of unknown type.