Abstract The crystal structure of (η 5-C 5H 5)Fe(CO) 2NCS has been determined by single crystal X-ray methods. The title compound has a monoclinic unit cell with a 6.400(6), b 7.907(4), c 9.115(8) Å and γ 91.48(8)° containing two formula units. The space group is P 2 1 m and the calculated density is 1.69g cm -3. The structure was refined by least-squares methods to a conventional R index of 0.10 using multiple-film equi-inclination Weissenberg data. The FeNCS fragment is essentially linear and the FeNCS and FeCO linkages are approximately orthogonal. The shortest non-bonded Fe…S interaction is 4.52(1) Å.