TRICLINIC FORM OF TETRAAQUA(OROTATO-N,O)MAGNESIUM(II) HYDRATE AT 153 K

In the title complex, [Mg(C5H2N2O4)(H2O)(4)].H2O, erotic acid (uracil- 6-carboxylic acid or 1,2,3,6-tetrahydro-2, 6-dioxo-4-pyrimidinecarboxy lic acid) coordinates to Mg through the deprotonated heterocyclic N1 a tom and the O atom of the adjacent carboxylate group. The coordination sphere of the Mg atom is octahedral with water molecules occupying th e four remaining coordination positions. The bond lengths in the coord ination sphere are in the range 2.0128 (13) to 2.1295 (13) Angstrom fo r the Mg-O bonds and 2.1663 (14) Angstrom for the Mg-N bond. The C=O b ond lengths for the exocyclic O2 and O4 atoms of the orotato Ligand ar e 1.247 (2) and 1.249 (2) Angstrom, respectively.