Two bis(ammonium) 1,5-naphthalenedisulfonate salts.

The title compounds, bis(ammonium) naphthalene-1,5-disulfonate, 2NH(4)(+).C(10)H(6)O(6)S(2)(2-), and bis[1-(hydroxymethyl)-3,5,7-triaza-1-azoniatricyclo[3.3.1.1(3,7)]decane] 1,5-naphthalenedisulfonate, 2C(7)H(15)N(4)O(+).C(10)H(6)O(6)S(2)(2-), were prepared from the acid-promoted reaction of hexamethylenetetramine. In both structures, the disulfonate anion is positioned on an inversion center, with each sulfonate group contributing to the supramolecular assemblies via hydrogen bonds. The ammonium cations are linked to sulfonate groups by four distinct N(+)-H.(-)O-S contacts [N.O = 2.846 (2)-2.898 (2) A and N-H.O = 160 (2)-175 (2) degrees ], whereas the 1-(hydroxymethyl)-3,5,7-triaza-1-azoniatricyclo[3.3.1.1(3,7)]decane cations form one O-H.(-)O-S [O.O = 2.628 (2) A and O-H.O = 176 degrees ] and three C-H.(-)O-S [C.O = 3.359 (2)-3.380 (2) A and C-H.O = 148-155 degrees ] interactions to neighboring sulfonate groups.