1. Nitrite   S2O3   NO2   Cr2O7   PO3   Hint Half-n-half Clue   2. Permanganate   SCN   S2O3   MnO4   ClO   Half-n-half Clue   3. Perbromate   IO4   BrO2   BrO4   NO2   Half-n-half Clue   4. Hypochlorite   PO3   ClO   ClO2   IO4   Half-n-half Clue   5. Peroxide (O2)   O2   CN   IO4   CNO   Half-n-half Clue   6. Iodite   S2O3   C2O4   IO2   SCN   Half-n-half Clue   7. Cyanide   CNO   CN   Cr2O7   CrO4   Half-n-half Clue