To-do-list (or attempt to eventually): NB! The times below have been postponed until further notice which is perhaps during summer.

• considering a thorough answer wrt reaction spontaneity with derivations and motivation for definitions; update 8th of February 2018: in progress, ccc 16 500.

• answer Le Chatelier's principle: Are there any exceptions? – in progress, current character count (ccc): 3000 5000, fully complete hopefully in February; update (31st January 2018): literature overview...

• answer Cerium & siloxene luminescence

• add to and modify Historical aspects of amine vs ammine

Archive

[Archived 12th January 2018] In progress (collecting information, translating, pondering implications of collected data):

• complete answering Metals and aqua regia

EDIT: After consulting with a disturbing amount of literature, I have been unable to come up with a definitive source as to explain the non-occurance. My current understanding: no single compound is to blame. Most likely it's a mix of chlorides, oxochlorides, their hydrates, hydroxidochlorides, its hydrates and the different crystalline forms of these compounds. I wish there were a simpler answer. I doubt there is.