Structural characterization of 1:1 adducts of silver(I) (pseudo-) halides (AgX, XÂ =Â NCO, Cl, Br, I) with Ph2E(CH2)EPh2 (EÂ =Â P, As) ('dp(p/a)m') and 4:3 adducts of copper(I) halide (CuX, XÂ =Â Cl, Br, I), containing trinuclear cations, of the form [X2A

Syntheses, spectroscopic and structural characterizations are reported for 1:1 adducts of bis(diphenylphosphine)methane ('dppm') with silver(I) (pseudo-)halides, AgX (X = Cl, Br, I, NCO), and for their arsenic ('dpam') Cl, NCO counterparts AgX:dpam (1:1), also for an array of 4:3 adducts of copper(I) halides (CuX, X = Cl, Br, I) with dppm. All species (the novel molecular [(OCN)3 Ag3(dpam)3] excepted) contain trinuclear cations, as [X2A3g(dpem)3]X(· nS) and [X2Cu3(dppm)3](CuX2)(· nS).