General Chemistry
CaO < Rb2O < As2O5 < Ga2O3 < SO2
As2O5 < Rb2O < CaO < SO2 < Ga2O3
SO2 < Ga2O3 < CaO < As2O5 < Rb2O
Rb2O < CaO < Ga2O3 < As2O5 < SO2