On the face of it without knowing the structure it would be -2 however that would imply an oxidation number for Cs of +6. Fortunately this compound does not exist which explains the weird oxidation number for Cs. There is a compound Cs11O3 and we get a fractional oxidation number of 6/11- Cs11O3 must contain some Cs-Cs bonding.
C- "+4" and S- "-2"
Ru has oxidation number +8, O has oxidation number of -2
The overall oxidation number is -2 so the average oxidation number of O is -1.
Oxidation number of chlorine is +7. oxidation number of O is -2.
The oxidation number for H is +1, and the oxidation number for O is -1.
Oxidation number of Si is +4.Oxidation number of O is -2.
Ru has oxidation number +8, O has oxidation number of -2
The overall oxidation number is -2 so the average oxidation number of O is -1.
Oxidation number of chlorine is +7. oxidation number of O is -2.
The oxidation number for H is +1, and the oxidation number for O is -1.
Oxidation number of Si is +4.Oxidation number of O is -2.
Oxidation number of Nb is +4. Oxidation number of O is -2.
Oxidation number of N is +1. Oxidation number of O is -2.
Oxidation number of C is +3. Oxidation number of O is -2.
Oxidation number of Ti is +2. Oxidation number of O is -2.
Oxidation number of o is -2. Oxidation number of H is +1.
Oxidation number of Se is +6. Oxidation number of O is -2.
The oxidation number of O in any elemental form (e.g. O2, O3) is zero. Typically in chemical compounds the oxidation number of O is -2 (oxide ion)