::So there is a gamma-U, G written in the text if you are right you have gas with a certain crystal structure. This is stupid! The whole article shows clearly that they had no method neither intention to do any reasearch about liquids or gas. So they were not able to do a clear identification which molecules are there in gasphas. Determining some physical properties of the gas at this temperatures which would lead to the exact chemical formula I simply cann't find in the text. So a missing comma is the only plausible explanaiton for this diagramm.