Assuming 100 g of the compound
Moles Ca = 19.4 / 40 = 0.485 moles
Moles Cl = 34.3 / 35.453 = 0.967 Moles
O = 46.3 / 16 = 2.894
Divide each number of moles by the lowest number of moles
Mole Ca = 0.485/ 0.485 =1
Moles Cl = 0.967 / 0.485 =2
Moles O = 2.894 / 0.485 = 6
So the empirical formula: CaCl2O6