Extensive hydrogen-bonding network and an unusual cation conformation in [tris-(hydroxy-meth-yl)methyl]-ammonium tetra-oxidorhenate(VII).

The title compound, (C(4)H(12)NO(3))[ReO(4)], contains two cations and two anions in the asymmetric unit, related by a non-crystallographic centre of symmetry. The crystal structure is stabilized by an extensive hydrogen-bonding network with the formation of puckered layers perpendicular to [001]. In the tris-(hydroxy-meth-yl)ammonium cations, intra-molecular O-H⋯O hydrogen bonds are present with the formation of an S(1) (1)(6) graph-set motif. The crystal structure is further consolid-ated by N-H⋯O hydrogen bonds.