Experimental Crystal data

R factor = 0.039; wR factor = 0.109; data-to-parameter ratio = 16.9. The title compound, C14H16O4P22H2O, possesses a crystal-lographic inversion center where two –P ( O)(OH)(C6H5) groups are joined together via two –CH2 groups. In the crystal, the acid molecules are linked by the water molecules via O— H O hydrogen bonds, leading to the formation of a two-dimensional network lying parallel to (101). Related literature For background on related phosphine macrocycles, see