Synthesis and Crystal Structure of Lithium Tetrametaphosphimate Tetrahydrate Li 4 (PO 2 NH) 4 · 4 H 2 O

Single crystals of Li 4 (PO 2 NH) 4 · 4 H 2 O were obtained by dissolving LiOH and H 4 (PO 2 NH) 4 · 2 H 2 O in water and subsequent precipitation with acetone and ethanol followed by slow evaporation of the solvents. The structure of Li 4 (PO 2 NH) 4 · 4 H 2 O was solved by single‐crystal X‐ray methods ( $P{\bar 1}$ (No. 2), a = 489.2(2), b = 853.2(2), c = 880.5(2) pm, α = 101.71(3), β = 102.39(3), γ = 94.88(3)°, Z = 1). The structure is composed of LiO 4 tetrahedra and (PO 2 NH) 4 4− ions. The P 4 N 4 rings of the anions exhibit a slightly distorted chair–1 conformation, which is supported by IR data and has been described by torsion angles, displacement asymmetry parameters and puckering parameters. Via Li + ions and hydrogen bonds, the tetrametaphosphimate anions are connected forming a three‐dimensional network.