[Co(NH3)4 H2O Cl]Cl2
One of the possible structures for unknown compound X2. The trans Cl and H2O molecule provide the most stable conformation (-475.5923 kcal/mol vs. -350.7312 kcal/mol for cis structure). The water molecule is most likely coordinately bound to the central cobalt atom. A molecule with two Cl atoms bound to the cobalt and the water molecule on the outside has an energy of is -297.3907 kcal/mol, making it the least stable conformation with this molecular formula (calculate using CaChe).