Structural changes due to the ordered guest molecules in deuterated ethane hydrate

Ethane hydrate, a natural gas hydrate, has been considered to only have a cubic symmetry known as structure I. Neutron diffraction measurement of deuterated ethane hydrate was performed from 10 K to 150 K. The diffraction patterns of deuterated ethane hydrate drastically changed below 30 K. A new hexagonal crystal structure with ordered ethane molecules was found as a clathrate hydrate structure. This phase transition was concerned with the thermal motion of the ethane molecules.

Automated summary

Neutron diffraction measurements revealed a significant structural change in deuterated ethane hydrate below 30K, resulting in a new hexagonal crystal structure with ordered ethane molecules.