The formula of an iodate of lanthanum is la (io3) 3. what is the formula of the sulfate of lanthanum with the same oxidation number

Iodate has a charge of - 1, this means its chemical symbol must be IO3 (-1) while Lanthanum is La (+3). Therefore making the compound La (IO3) 3.

However sulfate has a chemical symbol of SO4 (-2), it has charge of - 2, therefore the formula for lanthanum sulfate is:

La2 (SO4) 3