Ammonium violurate: a compact structure with extensive hydrogen bonding in three dimensions

Area of Science:

• Crystallography
• Chemical Crystallography
• Solid-State Chemistry

Background:

• Ammonium violurate is a compound with the chemical formula NH(4)(+).C(4)H(2)N(3)O(4)(-).
• The crystal structure of a related rubidium complex has been previously reported.
• Understanding the solid-state structure of ionic compounds is crucial for predicting their properties.

Purpose of the Study:

• To determine the crystal structure of ammonium violurate.
• To investigate the hydrogen bonding network within the ammonium violurate crystal lattice.
• To compare the structural features of ammonium violurate with its rubidium analogue.

Main Methods:

• Single-crystal X-ray diffraction was employed to analyze the crystal structure.
• The compound was crystallized from water.
• The crystal system and space group were determined (triclinic, P\overline{1}).

Main Results:

• Ammonium violurate crystallizes in the triclinic space group P\overline{1} and is isomorphous with a known rubidium complex.
• A significant feature of the structure is extensive hydrogen bonding involving both the ammonium cations and violurate anions.
• Ammonium cations act as bifurcated hydrogen bond donors, while violurate anions feature bifurcated and trifurcated oxygen acceptors.
• Violurate anions form hydrogen-bonded 'crinkled tapes' that are interconnected by ammonium cations, resulting in a compact 3D structure.

Conclusions:

• The crystal structure of ammonium violurate reveals a complex hydrogen bonding network.
• The hydrogen bonding pattern around the cation resembles the rubidium coordination environment in the related structure.
• The arrangement of ions leads to a stable and compact three-dimensional crystal structure.