Rb = + 1
S = + 4
O = - 2
Oxidation states of the elements were calculated keeping in mind the basic rules of assigning oxidation states which included assignment of +1 charge to first group elements i.e. Rubidium (Rb) and assignment of -2 charge to Oxygen atom. Then the oxidation state of Sulfur was calculated as follow,
Rb₂ + S + O₃ = 0
Above zero (0) means that the overall molecule is neutral.
Putting values of Rb and O,
(+1)₂ + S + (-2)₃ = 0
(+2) + S + (-6) = 0
+2 + S - 6 = 0
S - 6 = -2
S = -2 + 6
S = + 4
