An unusual coordination polymer containing Cu+ ions and featuring possible Cu⋯Cu `cuprophilic' inter­actions: poly[di-μ-chlorido-(μ4-3,5-di­amino­benzoato-κ4O:O′:N:N′)tricopper(I)(3 Cu—Cu)]

Compounds containing copper(I) are of interest for their role in biological processes. The nature of short (< 3.2 A˚ ) CuCu contacts within these compounds has been debated, being either described as weakly attractive (bonding) ‘cuprophilic’ interactions, or simply as short metal–metal distances constrained by ligand geometry or largely ionic in nature. The title threedimensional Cu+ -containing coordination polymer, [Cu3(C7H7N2O2)Cl2]n, was formed from the in situ reduction of CuCl2 in the presence of 3,5-diaminobenzoic acid and KOH under hydrothermal conditions. Its complex crystal structure contains ten distinct CuI atoms, two of which lie on crystallographic inversion centres. The copper coordination geometries include near-linear CuOCl and CuN2, T-shaped CuOCl2 and distorted tetrahedral CuOCl3 groups. Each CuI atom is also associated with two adjacent metal atoms, with CuCu distances varying from 2.7350 (14) to 3.2142 (13) A˚ ; if all these are regarded as ‘cuprophilic’ interactions, then infinite [101] zigzag chains of CuI atoms occur in the crystal. The structure is consolidated by N—HCl hydrogen bonds.