The charges on the three oxygen anions add up to
–
6. Each iron cation must have a charge of
+
3.
The charge on the single oxygen anion is
–
2. The iron cation must have a charge of
+
2.
The charges on the three oxygen anions add up to –6. Each iron cation must have a charge of +3.
The charge on the single oxygen anion is –2. The iron cation must have a charge of +2.