Cerium , 99%(REO) , 7440-45-1
Synonym(s):
;Cerium
CAS NO.：7440-45-1
Empirical Formula: Ce
Molecular Weight: 140.116
MDL number: MFCD00010924
EINECS: 231-154-9
PRODUCT Properties
| Melting point: | 795 °C (lit.) |
| Boiling point: | 3443 °C (lit.) |
| Density | 6.67 g/mL at 25 °C (lit.) |
| solubility | soluble in dilute acid solutions |
| form | powder |
| Specific Gravity | 6.9 |
| color | Silver-gray |
| Resistivity | 73 μΩ-cm, 20°C |
| Water Solubility | soluble dilute mineral acids [KIR78] |
| Sensitive | Air & Moisture Sensitive |
| Merck | 13,2003 |
| Exposure limits | ACGIH: TWA 2 ppm; STEL 4 ppm OSHA: TWA 2 ppm(5 mg/m3) NIOSH: IDLH 25 ppm; TWA 2 ppm(5 mg/m3); STEL 4 ppm(10 mg/m3) |
| CAS DataBase Reference | 7440-45-1(CAS DataBase Reference) |
| EPA Substance Registry System | Cerium (7440-45-1) |
Description and Uses
Cerium is a rare earth metal and the most abundant member of the lanthanide series discovered by Jons J. Berzelius and W. von Hisinger in 1803 in Sweden. Berzelius and Hisinger discovered the new element in a rare reddish-brown mineral now known as cerite, a cerium–lanthanide silicate. Although they could not isolate the pure metal, they found that cerium had two oxidation states: trivalent state (Ce3+, cerous, usually orangered) and the tetravalent state (Ce4+, ceric, usually colorless). Cerium is the only material known to have a solid-state critical point.
Cerium metal finds wide application in mischmetal, which is a rareearth metal comprised of 50% Ce, 25% La, 18% Nd, 5% Pr, and 2% other rare earths. This alloy is used in shell linings for military projectiles, as an alloying agent for improving the malleability of ductile iron, and in lighter “flints” where the alloy is compounded with a 30% iron alloy. The pyrophoric and incendiary nature of cerium are evident when ceriumbase alloys are machined. Mischmetal also improves the creep resistance of magnesium alloys, the resistance to oxidation of nickel alloys, the hardness of copper alloys, and the strength of aluminum alloys. Both cerium metal and mischmetal are used as getters to remove traces of oxygen in vacuum tubes and equipment. When alloyed with cobalt, cerium is gaining importance as a magnet material. CeCo5, as a permanent magnet material, has properties that exceed those of the alnicos and ferrites. Mixed rare-earth oxides and fluorides containing up to 50% cerium are used as cores for carbon arcs which, for illuminating purposes, have much greater intensity and color balance. The mixed oxides with cerium also are used as catalysts (petroleum cracking and chemical oxidation reactions) and in a variety of waterproofing agents, fungicides, and polishing materials.
Safety
| Symbol(GHS) |  GHS02 |
| Signal word | Danger |
| Hazard statements | H228 |
| Precautionary statements | P210-P240-P241-P280-P370+P378 |
| Hazard Codes | C,Xn,F |
| Risk Statements | 22-23-36/38-36/37/38-20/21/22-11-15-14/15 |
| Safety Statements | 26-36-36/37/39-16-43 |
| RIDADR | UN 2031 8/PG 2 |
| WGK Germany | 3 |
| F | 10 |
| TSCA | Yes |
| HazardClass | 4.1 |
| PackingGroup | II |
| HS Code | 28053090 |
