Clathrate Hydrate Structure II Puzzle

Clathrate hydrate is a solid solution made of gas and water. Methane hydrate is the most famous clathrate hydrate, but many other gases also form the clathrate hydrate.

Its crystal structure is quite complicated. In clathrate hydrates, the gas molecules are contained in the cages made of water molecules. There are three major type of cages, 12-, 14- and 16-hedra. Methane hydrate consists of 12- and 14-hedra, whereas hydrogen hydrate is composed of 12- and 16-hedra.

The unit cell of the