Vanadium has four stable ions in solution which exist in oxidation states +2, +3, +4 and +5.
Vanadium (V) can be reduced by adding it to Zinc metal in an acidic solution. The solution turns from yellow to blue to green to violet
| +5 | VO2+(aq) | yellow | ||
| +4 | VO2+(aq) | blue | ||
| +3 | V3+(aq) | green | ||
| +2 | V2+(aq) | violet |