Sciencemadness Discussion Board - Dehydratation of FeO(OH) and CaSO4

Dehydratation of FeO(OH) and CaSO4

Bedlasky - 24-4-2019 at 11:05

Hello.

I had some hydrated ferric oxide and calcium sulphate dihydrate from experiments I've made long ago. So I decided to dehydrated them in oven at 275°C. But I am little confused from result of this dehydration.

CaSO4 isn't white but beige. Is this normal or is it contaminated by some organic impurities?

Ferric oxide isn't red but black. Why?

fusso - 24-4-2019 at 21:50

Try magnet test. If it's attracted to magnet it's Fe3O4.

Ubya - 25-4-2019 at 01:09

most ferric oxide produced with wet chemistry is black. look at nurdrage's video on the preparation of ferric oxide for thermite, he uses 3 methods, and only the electrolytic one gives red iron oxide

Bedlasky - 30-4-2019 at 18:52

Quote: Originally posted by fusso

Try magnet test. If it's attracted to magnet it's Fe3O4.

I tried this and it had not attracted to magnet.

Quote: Originally posted by Ubya

most ferric oxide produced with wet chemistry is black. look at nurdrage's video on the preparation of ferric oxide for thermite, he uses 3 methods, and only the electrolytic one gives red iron oxide

Thanks!

CharlieA - 1-5-2019 at 16:14

Am I correct in assuming that Fe3O4 is a typo? Or is this FeO(dot)Fe2O3. I am not familiar with this substance.

oberkarteufel - 1-5-2019 at 23:55

No, it's not a typo. This compound contains iron on both +III and +II oxidation states. There's also an oxide Pb3O4 with +II and +IV lead atoms.

Edit: Naturally occuring Fe3O4 is known as magnetite.

[Edited on 2-5-2019 by oberkarteufel]

CharlieA - 2-5-2019 at 17:18

Quote: Originally posted by oberkarteufel

No, it's not a typo. This compound contains iron on both +III and +II oxidation states. There's also an oxide Pb3O4 with +II and +IV lead atoms.

Edit: Naturally occuring Fe3O4 is known as magnetite.

Thank you. I have learned something and that is a good think

Charlie A