Layered poly[mu2-aqua-mu3-dimethylformamide-di-mu3-phenylphosphonato-dipotassium].

The first structurally characterized alkali metal phosphonate, the title compound, [K2(C6H6O3P)2(C3H7NO)(H2O)]n, has a complex structure, with layers parallel to the crystallographic bc plane consisting of two crystallographically independent K atoms sandwiched between the three types of ligands present in the structure, viz. water molecules, dimethylformamide molecules and two crystallographically independent phenylphosphonate ligands. Six O atoms coordinate to one K atom and seven to the other. The interlayer distance is 15.327 (4) A. The K-O distances are in the range 2.739 (2)-2.932 (2) A for the seven-coordinate K atom and 2.650 (2)-2.821 (2) A for the six-coordinate K atom.