Question

Can anyone explain why it is so hard to dry inorganic salts?

Answer 1

Explain? Well, that is the way chemistry is.....the last waters of hydration cling to the metal centre tenaciously.....

Explanation:

If you have the facilities to store the DRIED complex, you can heat metal hydrates up in thionyl chloride, or better trimethylsilyl chloride at reflux, both of which solvents react with water bound to the metal centre. These are sometimes done in the presence of THF molecules, and we get chlorides of the form...`MCl_3*3THF`. The preparation of these so-called inorganic precursors can be found in `"Inorganic Syntheses"`, the which should be in your university library.