The low-temperature triclinic crystal structure of silver 3-sulfo­benzoic acid

Poly[(μ(4)-3-carboxybenzenesulfonato)silver(I)], Ag(O(3)SC(6)H(4)CO(2)H) or [Ag(C(7)H(5)O(5)S)](n), has been found to undergo a reversible phase transition from monoclinic to triclinic between 160 and 150 K. The low-temperature triclinic structure (space group P [Image: see text]) has been determined at 100 K. In contrast to the reported room temperature monoclinic structure, in which the nearly equivalent carboxyl­ate C—O distances indicate that the acidic hydrogen is randomly distributed between the O atoms, at 100 K the C—O (protonated) and C=O (unprotonated) bonds are clearly resolved, resulting in the reduction in symmetry from C2/c to P [Image: see text].