Crystal structure of pentasodium hydrogen dicitrate from synchrotron X-ray powder diffraction data and DFT comparison

Abstract

The crystal structure of pentasodium hydrogen dicitrate, Na5H(C6H5O7)2, has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Each of the two independent citrate anions is joined into a dimer by very strong centrosymmetric O—H...O hydrogen bonds, with O...O distances of 2.419 and 2.409 Å. Four octahedrally coordinated Na+ ions share edges to form open layers parallel to the ab plane. A fifth Na+ ion in trigonal–bipyramidal coordination shares faces with NaO6 octahedra on both sides of these layers.

Keywords

• powder diffraction
• crystal structure
• density functional theory
• citrate
• sodium