The ligating properties of Me3N(+)-N(-)X trimethylammonio-stabilised nitrogen ylides have been investigated. The electron-rich nitrogen atom of the ylide can be attached to silver(I) and mercury(II), giving rise to new solids with unusual architectures. The mono-ylide complex LAgNO3 [L=Me3N(+)-N(-)C(O)C6H4Cl-p] contains chains in which LAg units are mu(2)-bridged through nitrate oxygen atoms, whereas the di-ylide species L2AgNO3 [L=Me3N(+)-N(-)SO2C6H4CH3-p] contains L2Ag units with nearly linear coordination (N-Ag-N 158degrees); if account is taken of weaker Ag…O interactions the crystal is built from discrete L2AgNO3 molecules containing chiral tris(chelate)silver(I) ions which have spontaneously resolved during crystallisation. The ylide L=Me3N(+)-N(-)CO2Me forms catena-[LHgCl2] in which the planar LHgCl2 sub-units are weakly linked into chains through Hg…Cl contacts of 3.12 Angstrom. Treatment of L=Me3N(+)-N(-)C(O)C6H4Cl-p with HgCl2 leads to hydrolysis and formation of [LH][Hg2Cl5] which contains a novel [Hg2Cl5-](infinity) sheet structure formed by 2:1 association of linear HgCl2 molecules with dinuclear Hg2Cl62- anions. (C) 2003 Elsevier Ltd. All rights reserved.