One of the most interesting compounds in sulfur nitrogen fluorine chemistry is NdropSF(2)-N=S(=O)F-2 (3) (reported by Glemser and Hofer 30 years ago): in the NS backbone a triple and a double bond are connected by a single bond. Electrophiles (metal cations, fluoro Lewis acids, "CH3+") attack this multifunctional system exclusively at the thiazyl nitrogen of the triple bond. [M(NSF2NS(O)F-2)(4)][AsF6](2) (M = Ni (4b), Cu (4c)), [Re(CO)(5)(NSF2NS(O)F-2)][AsF6](-) (5), F(5)A(.)NSF(2)NS(O)F-2 (A = As (6), Sb (7)), (F3BNSF2NS)-N-.(O)F-2 (8) and [H3CNSF2NS(O)F-2](+)[AsF6](-) (9) were isolated. The X-ray structures of 4c, 6, 8 and 9 are reported, bonding in these complexes is compared with the recently reported related NSAr2NS(X)Ar-2 (X = O, NH) species. (C) 2004 Elsevier B.V. All rights reserved.