Crystal data for ammonium tri- and tetrapolyphosphates

Unit‐cell parameters and space groups have been determined on four ammonium polyphosphate salts. (NH4)5P3O10.2H2O is monoclinic with space group P21/n, a = 16.643, b = 6.719, c = 13.843, β = 98.61. (NH4)5P3O10.H2O is monoclinic, space group P2/n or Pn, a = 10.949, b = 10.377, c = 6.426, β = 91.06. (NH4)6P4O13.2H2O is triclinic, a =13.426, b = 11.874, c = 6.524, α = 93.80, β = 84.78, γ = 106.97. (NH4)4 H2P4O13 is orthorhombic, space group P22121, a = 13.359, b = 13.244, c = 8.214.