AM_SO3 Formula: S O3 Name: SO3 Unit cell: 6.2 4.06 9.31 90.0 109.83 90.0 , V=220.46 Space group: P121/C1 (14)

Westrik R , MacGillavry C H , Acta Crystallographica , 7 (1954) p.764-767, The crystal structure of the asbestos-like form of sulphur trioxide