Assuming you are trying to create a neutral compound, then yes, that is correct. In order to get a neutral compound, you need to balance the charges between the ions within the compound. You have 3 sulfur ions per molecule, each with a -2 charge, totaling a -6 charge. You have 2 scandium ions per molecule, each with a +3 charge, totaling a +6 charge. The +6 and -6 cancel each other, giving you a neutral compound.