The crystal structure of the title salt, ([H3NOH](+))3·[PO4](3-), consists of discrete hydroxyl-ammonium cations and ortho-phos-phate anions. The atoms of the cation occupy general positions, whereas the anion is located on a threefold rotation axis that runs through the phospho-rus atom and one of the phosphate O atoms. In the crystal structure, cations and anions are linked by inter-molecular O-H⋯O and N-H⋯O hydrogen bonds into a three-dimensional network. Altogether, one very strong O-H⋯O, two N-H⋯O hydrogen bonds of medium strength and two weaker bifurcated N-H⋯O inter-actions are observed.
Keywords: crystal structure; hydrogen bonding; hydroxylammonium salt.