Channel hydrates

The main features of these hydrates are water filled one dimensional channels or two dimensional planes running through the crystal structure. These can be more or less vast in diameter, ranging from sufficient space to accommodate just a single molecule of water to big pores or layers accommodating several water molecules not having contact to the host network. Obviously, the bigger the channels or planes are, the easier the water molecules can be removed from them. Thus, the channel hydrates with bigger pores represent most often non-stoichiometric hydrates. The channel hydrates with sufficiently big pores can show both stoichiometric and non-stoichiometric behaviour. The water molecules in the centre of the pores can exchange relatively easily with the surrounding atmosphere and behave non-stoichiometrical, while the water molecules closer to the pore’s walls will have more interaction with the host molecules and show less freedom. Additionally, removing all water molecules from the pores can render a crystal network of unsufficient stability due to now oversized channels, which leads to the collapse of the crystal architecture and either amorphisation of the solid or recrystallisation into a non-solvated crystal form.