Zn(O3PCH2OH) (1) has been formed by reaction of zinc acetate with diethyl hydroxymethylphosphonate. The acidity of the zinc solution effects hydrolysis of the phosphonate to produce phosphonic acid in situ. 1 crystallizes in the trigonal spacegroup R (3) over bar, with a 15.9701(2) Angstrom, c = 7.783(2) Angstrom, and Z = 18. The compound has channels in the [001] direction, formed by phosphonate groups bridging the octahedral coordinated zinc atoms. The zinc atoms are coordinated by the three oxygens of the phosphonate group and the oxygen of the hydroxy group.