Di-ammonium potassium citrate, (NH₄)₂KC₆H₅O₇

Area of Science:

• Crystallography
• Materials Science
• Inorganic Chemistry

Background:

• Understanding the crystal structure of citrate salts is crucial for applications in various chemical fields.
• Di-ammonium potassium citrate is a specific salt with potential applications that warrant structural investigation.

Purpose of the Study:

• To determine and refine the crystal structure of di-ammonium potassium citrate (2NH₄ ⁺·K⁺·C₆H₅O₇ ^3-).
• To elucidate the coordination environment, intermolecular interactions, and hydrogen bonding within the crystal lattice.

Main Methods:

• X-ray powder diffraction (XRD) for crystal structure determination and refinement.
• Density Functional Theory (DFT) for structural optimization.

Main Results:

• The crystal structure was solved and refined, revealing isolated KO₇ coordination polyhedra.
• Ammonium cations and hydrophobic methylene groups of citrate anions occupy spaces between polyhedra.
• Extensive charge-assisted hydrogen bonding (N-H⋯O) was observed involving all ammonium hydrogen atoms.
• An intramolecular O-H⋯O hydrogen bond was identified within the citrate anion.

Conclusions:

• The study provides a detailed structural characterization of di-ammonium potassium citrate.
• The identified hydrogen bonding network plays a significant role in stabilizing the crystal structure.
• The findings contribute to the understanding of citrate salt structures and their interactions.