|
| | Trimanganese tetraoxide Chemical Properties |
| Melting point | 1705°C | | density | 4.8 g/mL at 25 °C(lit.) | | vapor pressure | 0Pa at 25℃ | | form | Powder | | color | brown | | Specific Gravity | 4.856 | | Water Solubility | insoluble H2O [KIR81]; soluble HCl, releasing Cl2 [MER06] | | Merck | 13,5759 | | Stability: | Stable. | | CAS DataBase Reference | 1317-35-7(CAS DataBase Reference) | | EPA Substance Registry System | Manganese tetraoxide (1317-35-7) |
| Hazard Codes | Xi | | Risk Statements | 36/37/38 | | Safety Statements | 26-36 | | WGK Germany | 2 | | RTECS | OP0895000 | | Toxicity | mouse,LC,inhalation,> 3608ug/m3/2H (3.608mg/m3),American Industrial Hygiene Association Journal. Vol. 41, Pg. 494, 1980. |
| | Trimanganese tetraoxide Usage And Synthesis |
| Physical Properties | Black tetragonal crystal; exhibits two allotropic modifications—a stable alpha phase, occurring in tetragonal crystalline form (as hausmannite) and an unstable beta modification; Moh’s hardness 5.5; insoluble in water; soluble in hydrochloric acid.
| | Occurrence and Use | Manganese(II,III) oxide occurs in nature as the mineral hausmannite [1309-55-3]. It is used to make ferrites and thermistors. The oxide also is used in the thermite process for producing manganese.
| | Preparation | Manganese(II,III) oxide is made by heating manganese(IV) oxide, MnO2, or manganese(III) oxide, Mn2O3, above 950°C. When Mn2O3 is heated in air, the temperature should be above 940°C, but if heated in oxygen, the temperature should be above 1,090°C. Also, heating manganese(III) oxide at 230°C in hydrogen yields Mn3O4. However, further heating above 300°C converts Mn3O4 formed to green manganese(II) oxide, MnO.
Manganese(II,III) oxide also is obtained by heating the dioxide, MnO2, with carbon at 600 to 700°C.
| | Reactions | Manganese(II,III) oxide reacts with dilute acids forming the corresponding manganous salt and manganese(IV) oxide, MnO2:
Mn3O4 + 2H2SO4 → 2MnSO4 + MnO2 + 2H2O
The oxide, however, dissolves slowly in cold sulfuric acid forming a red solution that also contains manganic sulfate, Mn2(SO4)3:
Mn3O4 + 4H2SO4 → MnSO4 + Mn2(SO4)3 + 4H2O
Reaction with acetic acid yields manganese(II) acetate and manganese(III) oxide:
Mn3O4 + 2CH3COOH → Mn(CH3COO)2 + Mn2O3 + H2O
Manganese(II,III) oxide is reduced to manganese metal when heated with powdered aluminum (the Thermite process). The reaction is vigorous and exothermic:
3Mn3O4 + 8Al → 4Al2O3 + 9Mn
| | Chemical Properties | Grass-green powder.
but converted to Mn
3O4 if heated in air. Soluble in
acids; insoluble in water. Noncombustible. | | Uses | Textile printing, analytical chemistry, catalyst
in manufacture of allyl alcohol, ceramics, paints,
colored glass, bleaching tallow, animal feeds, fertilizers, food additive and dietary supplement. | | General Description | Manganese(II,III) oxide is a transition metal oxide that is formed by annealing manganese oxide in the air above 1000°C. It can be used for a variety of applications such as catalysis, electrochromic devices, and other energy storage applications. | | Reactivity Profile | Trimanganese tetraoxide is non-combustible but decomposes, generating toxic fumes when strongly heated strongly in the air. A good oxidizing agent. Reacts with hydrochloric acid to form gaseous chlorine and soluble manganese salts.
| | Hazard | Chronic manganese poisoning and pulmonary effects. | | Health Hazard | Manganese tetroxide affects the
central nervous system, and toxicity occurs
mostly in chronic form (manganism). | | Flammability and Explosibility | Nonflammable | | Safety Profile | Experimental reproductive effects. Reacts violently @ <l00℃. See also MANGANESE COMPOUNDS. |
| | Trimanganese tetraoxide Preparation Products And Raw materials |
|
