MANGANESE (III) OXIDE Property

Melting point:

1080°C (dec.)

Density 

4.5 g/mL at 25 °C(lit.)

solubility 

insoluble in H2O

form 

Powder

color 

Black

Specific Gravity

4.5

Water Solubility 

Soluble in acid and ammonium chloride. Insoluble in water, alcohol and acetone.

Merck 

14,5737

Exposure limits

ACGIH: TWA 0.02 mg/m3; TWA 0.1 mg/m3
OSHA: Ceiling 5 mg/m3
NIOSH: IDLH 500 mg/m3; TWA 1 mg/m3; STEL 3 mg/m3

InChIKey

GEYXPJBPASPPLI-UHFFFAOYSA-N

CAS DataBase Reference

1317-34-6(CAS DataBase Reference)

EPA Substance Registry System

Manganese(III) oxide (1317-34-6)

Safety

Hazard Codes 

Xi

Risk Statements 

36/37/38

Safety Statements 

26-36

WGK Germany 

3

RTECS 

OP0915000

TSCA 

Yes

Toxicity

mouse,LD50,subcutaneous,616mg/kg (616mg/kg),Zhurnal Vsesoyuznogo Khimicheskogo Obshchestva im. D.I. Mendeleeva. Journal of the D.I. Mendeleeva All-Union Chemical Society. Vol. 19, Pg. 186, 1974.

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Warning

Hazard statements

H315Causes skin irritation

H319Causes serious eye irritation

H335May cause respiratory irritation

Precautionary statements

P261Avoid breathing dust/fume/gas/mist/vapours/spray.

P264Wash hands thoroughly after handling.

P264Wash skin thouroughly after handling.

P271Use only outdoors or in a well-ventilated area.

P280Wear protective gloves/protective clothing/eye protection/face protection.

P302+P352IF ON SKIN: wash with plenty of soap and water.

P305+P351+P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.

MANGANESE (III) OXIDE Chemical Properties,Usage,Production

Chemical Properties

manganese(III) oxide is a black, lustrous powder, sometimes tinged brown. Very hard.decomposes at 1080℃. Soluble in cold hydrochloric acid; not soluble in nitric acid (decomposes), hot sulfuric acid; insoluble in water. Noncombustible.

manganese(III) oxide is obtained by igniting manganese(IV) oxide or a manganese(II) salt in air at 800°C. It reacts slowly with cold dilute acids to form manganese(III) salts. Manganese(III) oxide occurs in nature as braunite (3Mn2O3.MnSiO3 ) and the monohydrate (Mn2O 3.H2O) occurs in the mineral manganite. The manganese(III) oxide crystal lattice contains Mn3+ and O2– ions. With concentrated alkalis, it undergoes disproportionation to give manganese(II) and manganese(IV) ions.

Uses

Manganese(III) oxide is used to produce ceramic magnets and semiconductors. Further, it serves as a precursor to lithium manganese oxide. In addition to this, it acts as a useful battery cathode.

Definition

In nature as manganite, a manganese ore.

Preparation

Anhydrous manganese(III) oxide is found as the mineral braunite, Mn2O3, while a hydrated form, Mn2O3.H2O, which is chemically more reactive, occurs as manganite. Manganese forms both anions and cations in oxidation state +3. Simple salts of tervalent manganese are not stable. However, complexes are more stable, the hexacyanomanganates(III) being an example: K3Mn(CN)6 is a red crystalline solid, isomorphous with potassium hexacyanoferrate(III) and slowly hydrolysed.
Manganese(III) oxide is formed as a grey solid by heating manganese(IV) oxide to 700°C for several hours:
4MnO2 ---> 2Mn203 + O2
It is converted into trimanganese tetroxide when heated above 940°C in air or reduced by hydrogen above 230°C. Hot concentrated hydrochloric acid is oxidized to chlorine by manganese(III) oxide:
Mn203 (s) + 6H + + 2e- ==2Mn2+ + 3H2O
Mn203 (s) + 6H + + 2Cl- ---> 2Mn2+ + 3H2O + Cl2

Hazard

Flammable in finely divided form. Toxic by inhalation of dust.

Flammability and Explosibility

Not classified

Safety Profile

Moderately toxic by subcutaneous and intratracheal routes. See also MANGANESE COMPOUNDS.