The reaction of AgClO4 with acyclic potential tridentate N,N,N',N',N"-pentamethyldiethylenetriamine (pmdeta) has given colorless crystals suitable for X-ray crystallography. The crystal structure (P2(1)/n, a = 14.413(1) angstrom, b = 25.270(2) angstrom, c = 16.130(1) angstrom, b = 103.012(1)degrees, V = 5723.7(8) angstrom(3), Z = 4, R = 0.0349) has been solved and refined. Three silver(I) ions connect four pmdeta ligands to produce discrete complex of [Ag-3(pmdeta)(4)](ClO4)(3). A pmdeta ligand is bridged to three silver(I) ions, and three other pmdeta ligands are chelated to each silver(I) center in a tridentate mode. Thus, the product is a rare tri-nuclear silver(I) complex with two different chemical environments. C-13 NMR and MAS C-13 NMR indicate that the tri-nuclear silver(I) complex is not rigid in solution. The contact angles and thermal analyses of the complex are measured and discussed.