Solid-state structure of free base guanidine achieved at last.

Area of Science:

• Crystallography
• Solid-state chemistry
• Molecular structure determination

Background:

• Guanidine, synthesized 148 years ago, is a fundamental organic compound.
• Despite its simplicity, its crystal structure remained undescribed until now.

Purpose of the Study:

• To elucidate the crystal structure of free base guanidine.
• To understand the molecular arrangement and intermolecular interactions in guanidine crystals.

Main Methods:

• Single-crystal X-ray diffraction analysis.
• Crystallographic data collection and structure refinement.

Main Results:

• The crystal structure of guanidine was successfully determined.
• Two symmetry-independent, Y-shaped guanidine molecules were identified in the unit cell.
• A hydrogen-bonding network interconnects the molecules, forming a layered structure.

Conclusions:

• The detailed crystal structure of guanidine provides fundamental insights into its solid-state behavior.
• The findings unveil a previously unknown structural characteristic of this important molecule.