Synthesis and Crystal Structure Determination by X‐Ray Powder Diffraction of Nickel Tetrametaphosphimate Octahydrate Ni2(PO2NH)4 · 8 H2O

Ni₂(PO₂NH)₄ · 8 H₂O is isotypic with M₂(PO₂NH)₄ · 8 H₂O (M = Mg, Mn, Co, Zn) and crystallizes in the space group P2₁/c, Z = 2, with a = 641.25(1), b = 1041.42(1), c = 1278.18(2) pm and β = 104.243(1)°. The structure is composed of Ni²⁺ and (PO₂NH)₄^4? ions as well as crystal water molecules. The P₄N₄ rings of the (PO₂NH)₄^4? ions exhibit a slightly distorted chair–2 conformation, which has been described by torsion angles, displacement asymmetry parameters and puckering parameters. The tetrametaphosphimate anions are connected forming layers. These layers are linked solely by hydrogen bonds, forming a three‐dimensional network.