Lithium dipotassium citrate monohydrate, LiKCHO(HO).

The crystal structure of dilithium potassium citrate monohydrate, Li·2K·CHO ·HO or LiKCHO·HO, has been solved by direct methods and refined against laboratory X-ray powder diffraction data, and optimized using density functional techniques. The complete citrate trianion is generated by a crystallographic mirror plane, with two C and three O atoms lying on the reflecting plane, and chelates to three different K cations. The KO and LiO coordination polyhedra share edges and corners to form layers lying parallel to the plane.

Structures of dipotassium rubidium citrate monohydrate, KRbCHO(HO), and potassium dirubidium citrate monohydrate, KRbCHO(HO), from laboratory X-ray powder diffraction data and DFT calculations.

The crystal structures of the isostructural compounds dipotassium rubidium citrate monohydrate, KRbCHO(HO), and potassium dirubidium citrate monohydrate, KRbCHO(HO), have been solved and refined using laboratory X-ray powder diffraction data, and optimized using density functional techniques. The compounds are isostructural to KCHO(HO) and RbCHO(HO), but exhibit different degrees of ordering of the K and Rb cations over the three metal-ion sites. The K and Rb site occupancies correlate well to both the bond-valence sums and the DFT energies of ordered cation systems.

Crystal structures of two isostructural compounds: a second polymorph of dipotassium hydrogen citrate, KHCHO, and potassium rubidium hydrogen citrate, KRbHCHO.

The crystal structures of a new polymorph of dipotassium hydrogen citrate, 2K·HCHO, and potassium rubidium hydrogen citrate, K·Rb·HCHO, have been solved and refined using laboratory powder X-ray diffraction and optimized using density functional techniques. In the new polymorph of the dipotassium salt, KO and KO coordination polyhedra share corners and edges to form a three-dimensional framework with channels parallel to the a axis and [111]. The hydrophobic methylene groups face each other in the channels.

Sodium dirubidium citrate, NaRbCHO, and sodium dirubidium citrate dihydrate, NaRbCHO(HO).

The crystal structures of sodium dirubidium citrate {poly[μ-citrato-dirubi-dium(I)sodium(I)], [NaRb(CHO)] } and sodium dirubidium citrate dihydrate {poly[di-aqua-(μ-citrato)dirubidium(I)sodium(I)], [NaRb(CHO)(HO)] } have been solved and refined using laboratory X-ray powder diffraction data, and optimized using density functional techniques. Both structures contain Na chains and Rb layers, which link to form different three-dimensional frameworks. In each structure, the citrate triply chelates to the Na cation.

Crystal structure of dilithium potassium citrate, LiKCHO determined from powder diffraction data and DFT calculations.

The crystal structure of poly[μ-citrato-dilithium(I)potassium(I)], [LiK(CHO)] , has been solved and refined using laboratory X-ray powder diffraction data, and optimized using density functional techniques. The citrate anion triply chelates to the K cation through the hydroxyl group, the central carboxyl-ate, and the terminal carboxyl-ate. The KO coordination polyhedra share edges, forming chains parallel to the axis.

Sodium rubidium hydrogen citrate, NaRbHCHO, and sodium caesium hydrogen citrate, NaCsHCHO: crystal structures and DFT comparisons.

The crystal structure of sodium rubidium hydrogen citrate, NaRbHCHO or [NaRb(CHO)] , has been solved and refined using laboratory powder X-ray diffraction data, and optimized using density functional techniques. This compound is isostructural to NaKHCHO. The Na atom is six-coordinate, with a bond-valence sum of 1.

Dilithium (citrate) crystals and their relatives.

New compounds of the type LiMHCHO (M = Li, Na, K, Rb) have been prepared from the metal carbonates and citric acid in solution. The crystal structures have been solved and refined using laboratory powder X-ray diffraction data, and optimized using density functional techniques. The compounds crystallize in the triclinic space group P-1 and are nearly isostructural.