The crystal and molecular structure of phosphoenolpyruvic acid

Phosphoenolpyruvic acid crystals, obtained by slow concentration of an aqueous solution, are triclinic, space group P1, with a = 5.905(5), b = 8.135(8), c = 14.095(15) A, alpha = 104.70(8), beta = 97.72(8), gamma = 100.99(8) degrees, and Z = 4. Two crystallographically independent phosphoenolpyruvic acid molecules differ in the orientation of the phosphate group relative to the enolpyruvate moiety. The phosphate groups have different tetrahedral distortions, and their P-O(ester) bond-lengths are 1.578(3) and 1.583(3) A. All OH groups are involved in intermolecular hydrogen bonds.