The extension of systematic structural definition of arrays of the form MX:EPh3 (1:n) (M = univalent coinage metal, X = (pseudo-)halide, E = P, As. Sb, n = integer (1-4)) into complexes of chelate congeners with ligands of the form 'dpex' (Ph2E(CH2)(x) EPh2):MX:dpex (1:n) is commenced. Syntheses, spectroscopic features and single crystal X-ray structural characterizations are reported for 1:1 adducts of bis(diphenylphosphine)methane ('dppm') with silver(1) (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 recorded here (the novel molecular [(OCN)(3)Ag-3(dpam)(3)] excepted) contain trinuclear cations, as [X(2)A(3)g(dpem)(3)]X((.)nS) and [X2Cu3(dppm)(3)](CuX2)((.)nS), enabling systematic comparison between a wide diversity of species. (C) 2004 Elsevier B.V. All rights reserved.