Theory 14/Phase & ice/Clathrates
Clathrates Need a Guest Fit
The claim
A clathrate forms only when the ratio of guest molecular size to cage size falls within a window, so gases too small or too large do not stabilise the structure.
01Mechanism
The cage is stabilised by van der Waals contact; too loose or too tight and the structure is not favoured.
02Prediction
Stability should peak at an intermediate size ratio.
03Refutation
Stability increasing with guest size would remove the window.