The synthesis and crystal structures of two three-dimensional sodium phosphinates are reported. While [Na-2 (CH2OH)(2)PO2}(2)(H2O)](n) (1) is formed from the direct reaction of bis(hydroxylmethyl)phosphinic acid with NaOH, the addition of 1,10-phenanthroline to the above reaction mixture results in the formation of [Na-2 (CH2OH)(2)PO2}(2)](n) (2). The basic structural unit of the 3D polymeric networks in both 1 and 2 is a dimeric Na2L2 moiety. In case of 1, these units are interconnected through coordination via phosphoryl and alcoholic oxygen atoms to eventually result in a three-dimensional network. However in the case of 2, only the phosphoryl oxygen is responsible for gluing the Na2L2 dimeric units into a three-dimensional framework. (C) 2010 Elsevier B.V. All rights reserved.