The title compound crystallizes in the triclinic space group P, with Z= 2 in a unit cell with a= 10·557(1), b= 10·043(1), c= 11·230(1)Å, α= 114·22(1), β= 91·95(1), γ= 92·25(1)°. The structure was solved by the heavy-atom method, from 3217 independent reflections measured by counter diffractometry. Refinement by least-squares methods gave R 0·024.

To a good approximation the molecule has C₃ symmetry with the Ph₃Sb ligand occupying an axial position in the trigonal-bipyramidal co-ordination sphere of the iron atom; Sb–Fe 2·472(1)Å. Mean Fe–C(eq) is 1·787(5), Fe–C(ax) 1·765(5)Å, indicating a slight trans-effect. The equatorial angles at Fe are 117·7, 118·7, and 123·4(2)° and the mean Sb–Fe–C(eq) angle is 88·3(1)°. Antimony is tetrahedrally co-ordinated, mean Sb–C 2·125(3)Å. Mean Fe–Sb–C and C–Sb–C angles are 116·4(1) and 101·8(2)°, indicating an enhanced s character in the Sb–Fe relative to the Sb–C bonds.