Ferrocene-1-carbaldehyde 4-ethyl­thio­semi­carbazone

The asymmetric unit of title compound, [Fe(C(5)H(5))(C(9)H(12)N(3)S)], contains two crystallographically independent mol­ecules, A and B. The two cyclo­penta­dienyl (Cp) rings are parallel to each other in both mol­ecules, forming dihedral angles of 2.3 (3) and 1.0 (3)°, respectively, and adopt an eclipsed conformation. The mean plane of the semicarbazone group is twisted slightly away from the attached Cp ring in both mol­ecules, the dihedral angles between the mean plane and the Cp ring being 15.3 (2) and 10.8 (2)°. The ethyl group in mol­ecule A is coplanar with the mean plane of the semicarbazone group [C—N—C—C torsion angle = −175.2 (4)°], whereas it is nearly perpendicular in mol­ecule B [C—N—C—C torsion angle = 84.8 (6)°]. In the crystal structure, inter­molecular N—H⋯S hydrogen bonds link the mol­ecules into dimers. These dimers are further linked into chains via inter­molecular C—H⋯S hydrogen bonds. The crystal studied was a non-merohedral twin with a refined ratio of the twin components of 0.265 (2):0.735 (2).