Sciencemadness Discussion Board

Synthesis of Mn oxides

blogfast25 - 21-4-2008 at 10:00

Does anybody here have some experience/ideas with synthesising MnO, Mn2O3 or Mn3O4? (NOT MnO2)

ScienceGeek - 21-4-2008 at 10:14

I found this in
"Laboratory Manual of Inorganic Preparations by Vulte 1895", page 164:

SOLUBLE MANGANESE OXIDE.
4(MnO 2 H 2 O),Mn 3 O 4 .

Obtained by acting on potassium permanganate with
sodium thiosulphate, and thoroughly washing the precipi-
tate with water. As soon as all the potassium has been
removed, a brown solution is obtained, from which the oxide
is precipitated on the addition of any salt. The manga-
nese solution can be kept for a long time in sealed tubes,
but if filtered through paper the manganese is completely
precipitated.

12AX7 - 21-4-2008 at 12:43

Um? Surely they meant colloidial or suspended manganese?

Heating MnO2 with good old charcoal affords you the various sorts, depending on stoichiometry, heat, etc.

Tim

Xenoid - 21-4-2008 at 13:38

Here's some information from my abridged Mellors:

MnOxides.jpg - 46kB

blogfast25 - 22-4-2008 at 08:41

Hmm, seems like the roasting of MnO2 with C (to CO and lower Mn oxide(s)) remains the easiest option...

blogfast25 - 24-4-2008 at 08:00

There may be an even easier way:

Dissolve MnO2 in strong HCl to MnCl2 (+II).

Precipitate with washing soda to MnCO3. Filter, wash and dry.

According to Wiki, the carbonate decomposes to MnO and CO2 at about 200 C, although preventing reoxidation of the MnO to dioxide may be difficult, dunno. I've made MnCO3 before.