Chloranilic acid: a redetermination at 100 K

Area of Science:

• Crystallography
• Solid-state chemistry

Background:

• The crystal structure of chloranilic acid was previously determined at room temperature in 1967.
• Chloranilic acid is an important compound with potential applications in materials science.

Purpose of the Study:

• To redetermine the crystal structure of chloranilic acid at a low temperature (100 K).
• To gain a more accurate understanding of its molecular geometry and intermolecular interactions.

Main Methods:

• Single-crystal X-ray diffraction at 100 K.
• Analysis of crystallographic data to determine molecular structure and packing.

Main Results:

• The chloranilic acid molecule is approximately planar, with minimal deviation from the mean plane.
• The crystal structure features a two-dimensional hydrogen-bonded network (O-H⋯O interactions) parallel to [101].
• Intermolecular Cl⋯Cl interactions (3.2838 Å) stabilize the packing of these layers.

Conclusions:

• The low-temperature redetermination provides a precise structural model for chloranilic acid.
• The identified hydrogen-bonding and Cl⋯Cl interactions are key to understanding the compound's solid-state properties.