text: As a ligand, NS acts as a σ-donor and π-acceptor, forming metal-thionitrosyl complexes. Transition-metal thionitrosyl complexes have been prepared by the following procedures:
  * Sulfur transfer to metal nitrido complexes
  ** Example: Reflux of (PhP)[OsNCl] and (PhP)NCS yields green-brown solid [PhP][Os(NS)(NCS)] 
  * Reaction of trithiazyltrichloride with transition metal complexes
  ** NSCl + OsCl > [Os(NS)Cl]
  * Halide abstraction from coordinated thiazyl complexes
  ** Abstraction of sulfur-bonded fluorine from [(ηCH)Cr(NO)(NSF)]-[AsF]  by AsF > [(η-CH)Cr(NO)(NS)]-[AsF]
  * Reaction of NS salts with transition metal complexes
  ** NSSbF + [M(CO)Br] > [M(CO)(NS)], M=Mn, Re 
  ** NSAsF + [(η-CH)Fe(CO)(SO)] > [(η-CH)Fe(CO)(NS)] [AsF]
  * Reaction of tetrasulfur tetranitride with metal halides or nitrides
  From X-ray crystallography of many of such metal-thionitrosyl complexes, one can observe that the M-N-S bond angle is nearly linear, suggesting sp hybridization about N. Short M-N distances and long N-S distances reflect the resonance structure of M=N=S having greater contribution than M-N≡S.
  Typical v(NS) IR stretching frequencies are approximately 1065 cm for low-valent transition metal complexes and around 1390 cm in the high valent cases, whereas the free gas-phase radical exhibits a 1204 cm signal.