| Description |
Hard, brittle, silvery metal. Reactive when impure and will
burn in oxygen. Surface oxidation occurs in air; will react with water,
dissolves in dilute acids. Used in steel production, animal feed
supplement, fertilizer additives, ceramics, etc. Diagnostic tests:
With borax bead test, manganese gives a bead color violet-red in oxidizing flame and
colorless in reducing flame. With soda (Na2CO3) and
an oxidizing flame the bead color is bluish green. These bead tests are
very sensitive and may be relied on even with the presence of other
metals.
In solution, color varies from light pink (Mn2+) to deep violet
(Mn7+) depending on oxidation state. Mn2+ is soluble
in (NH4)OH, forms a peach-tan precipitate using (NH4)2S.
The addition of NaOH to Mn2+ forms a brown precipitate of
Mn(OH)2 which turns black (Mn(OH)3)on the addition
of H2O2.
|
