manganese

Name manganese
Symbol Mn
Atomic Weight 54.938049
Atomic Number 25
CAS ID 7439-96-5
Group Number 7
Group Name (none)
Period Number 4
Origin of Name From the Latin, magnes = "magnet."
Year Discovered 1774
Discovery Credits Isolated by J. G. Grahn at Stockholm, Sweden.
Class Metallic
Color Silvery Metallic
Standard State Solid at 77 F & 298 K
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.

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