Syntheses, Crystal Structures and Properties of the Tetrametaphosphimates M II 2 (PO 2 NH) 4 · 8 H 2 O with M II = Mg, Mn, Co and Zn

Mg 2 (PO 2 NH) 4 · 8 H 2 O ( 1 ), Mn 2 (PO 2 NH) 4 · 8 H 2 O ( 2 ), Co 2 (PO 2 NH) 4 · 8 H 2 O ( 3 ) and Zn 2 (PO 2 NH) 4 · 8 H 2 O ( 4 ) were obtained as microcrystalline powders by combining aqueous solutions of K 4 (PO 2 NH) 4 · 4 H 2 O and MX 2 · y H 2 O (M = Mg, Mn, Co, Zn; X = Cl, NO 3 ). Single crystals were obtained by crystallization in gelatine gels in U‐tubes or test‐tubes. 2 and 4 were characterized by thermogravimetry and 4 was additionally characterized by temperature dependend in situ powder diffractometry. The structures of 1 , 2 , 3 and 4 were found to be isotypic and were solved by single‐crystal X‐ray methods: P 2 1 / c , Z = 2 ( 1 : a = 645.4(2), b = 1050.1(2), c = 1283.3(3) pm, β = 104.66(3)°; 2 : a = 648.7(2), b = 1063.1(2), c = 1310.8(3) pm, β = 103.93(3)°; 3 : a = 643.3(2), b = 1049.0(2), c = 1286.7(3) pm, β = 104.28(3)°; 4 : a = 644.18(5), b = 1049.22(7), c = 1282.43(8) pm, β = 104.122(6)°). The structure is composed of MO 6 octahedra and (PO 2 NH) 4 4— anions. The P 4 N 4 rings of the (PO 2 NH) 4 4— anions exhibit a slightly distorted chair conformation, which is supported by IR data and has been described by torsion angles, Displacement Asymmetry Parameters and Puckering Parameters. Via M 2+ ions and hydrogen bonds, the tetrametaphosphimate anions are connected forming layers perpendicular to [100]. These layers are connected by hydrogen bonds.