Benzyl­tributyl­ammonium 6,7-dihydroxy­naphthalene-2-sulfonate

The title mol­ecular salt, C(19)H(34)N(+)·C(10)H(7)O(5)S(−), is a charge-control agent used for toners in electrophotography. There are two formula units in the asymmetric unit. Both anions form inversion dimers connected by pairs of O—H⋯O hydrogen bonds between the –OH group of one anion and a sulfonic O atom of the neighboring one. The two dimers A and B are characterized by a step between the least-squares planes of the naphthalene atoms of 0.85 and 2.30 Å. Further O—H⋯O bonds link the dimers into a two-dimensional network propagating in (110) such that dimer A is hydrogen-bonded to four B units and vice versa. One of the tert-butyl chains in one of the cations is disordered over two sets of sites in a 0.56:0.44 ratio.