N—H...S and N—H...O hydrogen bonding in tetra-<i>n</i>-butylammonium (imidazolidine-2-thione-2κ<i>S</i>)dioxo-1κ<sup>2</sup><i>O</i>-di-μ-sulfido-1:2κ<sup>4</sup><i>S</i>:<i>S</i>-copper(I)tungstate(VI)
Acta crystallographica. Section E