(N(2))(6)Ne(7): A high pressure van der Waals insertion compound

Area of Science:

• Materials Science
• Solid State Chemistry
• Physical Chemistry

Background:

• Understanding the phase behavior of gas mixtures is crucial for various industrial and scientific applications.
• Nitrogen (N(2)) and Neon (Ne) are simple molecular substances with distinct properties, making their mixtures interesting for fundamental studies.

Purpose of the Study:

• To investigate the binary phase diagram of nitrogen-neon mixtures at 296 K.
• To identify and characterize any novel stoichiometric compounds formed within these mixtures.
• To elucidate the structural and bonding characteristics of any discovered compounds.

Main Methods:

• Visual observation of phase transitions.
• Raman spectroscopy for chemical identification and structural analysis.
• Single-crystal synchrotron X-ray diffraction for precise structure determination.

Main Results:

• The binary phase diagram of N(2)-Ne mixtures at 296 K was successfully mapped.
• Evidence for a stoichiometric compound, N(2))(6)Ne(7), was identified.
• The crystal structure revealed N(2) molecules forming a guest lattice with Ne atoms encapsulated in distorted dodecahedron cages.
• This compound represents the first clathrate structure organized by quadrupolar interactions.

Conclusions:

• A novel clathrate compound, N(2))(6)Ne(7), has been synthesized and structurally characterized.
• The discovery highlights the role of quadrupolar interactions in clathrate formation.
• This finding expands the understanding of clathrate chemistry and the phase behavior of simple molecular systems.