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. 2020 May 12;5(Pt 5):x200612.
doi: 10.1107/S2414314620006124. eCollection 2020 May.

Di-ammonium potassium citrate, (NH4)2KC6H5O7

Nilan V Patel  1 , Joseph T Golab  1 , James A Kaduk  2
Affiliations

Di-ammonium potassium citrate, (NH4)2KC6H5O7

Nilan V Patel et al. IUCrdata. .

Abstract

The crystal structure of di-ammonium potassium citrate, 2NH4 +·K+·C6H5O7 3-, has been solved and refined using laboratory X-ray powder diffraction data and optimized using density functional theory. The KO7 coordination polyhedra are isolated. The ammonium cations and the hydro-phobic methyl-ene sides of the citrate anions occupy the spaces between the coordination polyhedra. Each hydrogen atom of the ammonium ions acts as a donor in a charge-assisted N-H⋯O, N-H⋯(O,O) or N-H⋯(O,O,O) hydrogen bond. There is an intra-molecular O-H⋯O hydrogen bond in the citrate anion between the hydroxide group and one of the terminal carboxyl-ate groups.

Keywords: ammonium; citrate anion; density functional theory; potasssium; powder diffraction.

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Figures

Figure 1
Figure 1
The asymmetric unit of (NH4)2KC6H5O7 with the atom numbering and 50% probability spheroids.
Figure 2
Figure 2
Comparison of the refined and optimized structures of (NH4)2KC6H5O7. The refined structure is in red, and the DFT-optimized structure is in blue.
Figure 3
Figure 3
The crystal structure of (NH4)2KC6H5O7, viewed along the a axis.
Figure 4
Figure 4
Overlay of the crystal structures of di­ammonium potassium citrate and tri­ammonium citrate, showing that they are isostructural.
Figure 5
Figure 5
Comparison of the X-ray powder diffraction patterns of di­ammonium potassium citrate (black) and tri­ammonium citrate (green).
Figure 6
Figure 6
Rietveld plot for (NH4)2KC6H5O7. The blue crosses represent the observed data points, and the green line is the calculated pattern. The cyan curve is the normalized error plot. The vertical scale has been multiplied by a factor of 10× for 2θ > 50.0°. The row of blue tick marks indicates the calculated reflection positions. The red line is the background curve.
See this image and copyright information in PMC

References

    1. Altomare, A., Cuocci, C., Giacovazzo, C., Moliterni, A., Rizzi, R., Corriero, N. & Falcicchio, A. (2013). J. Appl. Cryst. 46, 1231–1235.
    1. Bravais, A. (1866). Etudes Cristallographiques. Paris: Gauthier Villars.
    1. Bruker (2015). Data Collector. Bruker AXS Inc., Maddison, Wisconsin, USA.
    1. Bruno, I. J., Cole, J. C., Kessler, M., Luo, J., Motherwell, W. D. S., Purkis, L. H., Smith, B. R., Taylor, R., Cooper, R. I., Harris, S. E. & Orpen, A. G. (2004). J. Chem. Inf. Comput. Sci. 44, 2133–2144. - PubMed
    1. Crystal Impact (2015). DIAMOND. Crystal Impact GbR, Bonn, Germany.

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