Simplify the following text for a Grade 10 native English-speaking person.
Original: The hydrated ( with water molecules attached ) form is made by reacting any cobalt ( II ) compound with hydrofluoric acid . When fluorine is reacted with cobalt at a high temperature , it makes both cobalt ( II ) fluoride and cobalt ( III ) fluoride .
Simplified: The tetrahydrate cobalt ( II ) fluoride is formed by dissolving cobalt ( II ) in hydrofluoric acid .