The geometrically pure 'complex ligand' fac-[Ru(L(ph))3](2+), in which three pendant bidentate binding sites are located on one face of the complex, reacts with Ag(I) ions to form the adamantoid decanuclear cage [{Ru(L(ph))3}4Ag6](PF6)14 which contains a 6-coordinate Ru(II) ion at each vertex of a large tetrahedron and a 4-coordinate Ag(I) ion along each edge.