How can you make that compound if you are merely mixing the two solutions together? They are all ionic compounds and are soluble in water to produce its ions. So when you mix the two solutions toether, what you're getting in a solution with the 4 different ions in it. And that doesnt show that you've formed the compound you wanted right? The compound is only in aqueous state and how are you going to separate the ions of the compound that you want from the other two ions that you dont want?