The molecule is tetraanion of D-ribulose 1,5-bisphosphate arising from deprotonation of all four phosphate OH groups; major species at pH 7.3. It is a conjugate base of a D-ribulose 1,5-bisphosphate.
[(2R,3R)-2,3-dihydroxy-4-oxo-5-phosphonatooxypentyl] phosphate