Alagappa Rammohan

Sodium dipotassium citrate, NaK2C6H5O7

The crystal structure of sodium dipotassium citrate has been solved and refined using laboratory X-ray powder diffraction data, and optimized using density functional techniques. The Na and K cation coordination spheres share corners and edges to form a three-dimensional network.

Trisodium citrate, Na3(C6H5O7).

The crystal structure of anhydrous trisodium citrate has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. The five-, six-, and five-coordinate Na polyhedra share edges and corners to form a three-dimensional framework.

A second polymorph of sodium di­hydrogen citrate, NaH2C6H5O7: structure solution from powder diffraction data and DFT comparison

The crystal structure of a second polymorph of sodium dihydrogen citrate has been solved and refined using laboratory X-ray powder diffraction data, and optimized using density functional techniques. The powder pattern of a commercial sample did not match that corresponding to the known crystal structure (NAHCIT).

Crystal structure of anhydrous tripotassium citrate from laboratory X-ray powder diffraction data and DFT comparison.

The crystal structure of anhydrous tripotassium citrate has been solved and refined using laboratory X-ray powder diffraction data, and optimized using density functional techniques.

Crystal structure of trirubidium citrate monohydrate from laboratory X-ray powder diffraction data and DFT comparison

The crystal structure of trirubidium citrate monohydrate has been solved and refined using laboratory X-ray powder diffraction data, and optimized using density functional techniques.

Crystal structure of trirubidium citrate from laboratory X-ray powder diffraction data and DFT comparison

The crystal structure of trirubidium citrate has been solved and refined using laboratory X-ray powder diffraction data, and optimized using density functional techniques.

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

The crystal structure of pentasodium hydrogen dicitrate has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques.

Crystal structure of caesium di­hydrogen citrate from laboratory X-ray powder diffraction data and DFT comparison

The crystal structure of caesium dihydrogen citrate has been solved and refined using laboratory X-ray powder diffraction data, and optimized using density functional techniques.

Crystal structures of alkali metal (Group 1) citrate salts

The crystal structures of 16 new alkali metal citrates were determined using powder and/or single crystal techniques. These structures and 12 previously determined citrate structures were optimized using density functional techniques. The central portion of a citrate ion is fairly rigid, while the conformations of the terminal carboxylate groups exhibit no preferences. The citrate-metal bonding is ionic. Trends in metal-citrate coordination are noted. The energy of an O-H...O hydrogen bond is proportional to the square root of the H...acceptor Mulliken overlap population, and a correlation between the hydrogen bond energy and the H...acceptor distance was developed: E (kJ mol-1) = 137.5 (5) - 45.7 (8) (H...A, Å). The hydrogen bond contribution to the crystal energy ranges from 62.815 to 627.6 kJ mol-1 citrate-1 and comprises ∼5 to 30% of the crystal energy. The general order of ionization of the three carboxylic acid groups of citric acid is: central, terminal, terminal, although there are a few exceptions. Comparisons of the refined and DFT-optimized structures indicate that crystal structures determined using powder diffraction data may not be as accurate as single-crystal structures.

Crystal structure of dicesium hydrogen citrate from laboratory single-crystal and powder X-ray diffraction data and DFT comparison

The crystal structure of dicesium hydrogen citrate has been solved using laboratory X-ray single-crystal diffraction data, refined using laboratory powder data, and optimized using density functional techniques.