text: Most homoleptic complexes of NCS feature isothiocyanate ligands (N-bonded).  All first-row metals bind thiocyanate in this way.  Octahedral complexes [M(NCS)] include M = Ti(III), Cr(III), Mn(II), Fe(III), Ni(II), Mo(III), Tc(IV), and Ru(III).  Four-coordinated tetrakis(isothiocyanate) complexes would be tetrahedral since isothiocyanate is a weak-field ligand.  Two examples are the deep blue [Co(NCS)] and the green [Ni(NCS)].
  Few homoleptic complexes of NCS feature thiocyanate ligands (S-bonded). Octahedral complexes include [M(SCN)] (M = Rh and Ir) and [Pt(SCN)].  Square planar complexes include [M(SCN)]  (M = Pd(II), Pt(II), and Au(III)).  Colorless [Hg(SCN)] is tetrahedral.
  Some octahedral isothiocyanate complexes undergo redox reactions reversibly. Orange [Os(NCS)] can be oxidized to violet [Os(NCS)].  The Os-N distances in both derivatives are almost identical at 200 picometers.