Cesium , 99.98%metalsbasis , 7440-46-2
CAS NO.：7440-46-2
Empirical Formula: Cs
Molecular Weight: 132.91
MDL number: MFCD00134037
EINECS: 231-155-4
PRODUCT Properties
| Melting point: | 28.5 °C (lit.) |
| Boiling point: | 705 °C (lit.) |
| Density | 1.873 g/mL at 25 °C (lit.) |
| vapor pressure | 1 mm Hg ( 279 °C) |
| storage temp. | 2-8°C |
| solubility | H2O: soluble |
| form | ingot |
| color | Silver |
| Specific Gravity | 1.892 |
| PH | 0.5 (20°C in H2O) |
| Flame Color | Blue violet |
| Resistivity | 19 μΩ-cm, 0°C |
| Water Solubility | reacts with H2O to evolve H2; soluble liquid NH3 [MER06] |
| Sensitive | moisture sensitive |
| Merck | 13,2018 |
| 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) |
| Stability: | Flammable solid; highly flammable in powder form. Moisture-sensitive. Incompatible with chlorine, phosphorus, water. |
| Bulk Modulus | 1.57 GPa |
| CAS DataBase Reference | 7440-46-2(CAS DataBase Reference) |
| EPA Substance Registry System | Cesium (7440-46-2) |
Description and Uses
Cesium was discovered in 1860 by Robert Bunsen and Gustav Kirchoff. It is used in the most accurate atomic clocks. Cesium melts at 28.41°C (just below body temperature) and occurs in Earth’s crust at 2.6 ppm. Cesium is the rarest of the naturally occurring alkali metals as the isotope 133Cs. Its compounds are correspondingly rare. Granites contain about 1 ppm cesium and sedimentary rocks contain approximately 4 ppm cesium. The most common commercial source of cesium is pollucite, which contains between 5 and 32% cesium oxide. Radioactive forms of cesium (134Cs and 137Cs) can also be found in the environment. They are produced during nuclear fission, and are used in cancer treatment.
In photoelectric cells, as a "getter" in vacuum tubes; in photoemitter devices, scintillation counters. Adsorbent in CO2 purifn; scavenger of gases and impurities in metallurgy. For doping catalysts. For construction and operation of one type of atomic clock based on the vibrational frequency (9,192.76 megacycles/sec) of 133Cs. 137Cs in process control instruments, sewage and sludge sterilization.
Safety
| Symbol(GHS) |   GHS02,GHS05 |
| Signal word | Danger |
| Hazard statements | H260-H314 |
| Precautionary statements | P223-P231+P232-P280-P305+P351+P338-P370+P378-P422 |
| Hazard Codes | Xi,C,F |
| Risk Statements | 36/38-34-14/15-11 |
| Safety Statements | 26-45-43-36/37/39-16-8 |
| RIDADR | UN 3264 8/PG 3 |
| WGK Germany | 3 |
| RTECS | FK9225000 |
| F | 10 |
| TSCA | Yes |
| HazardClass | 4.3 |
| PackingGroup | I |
| HS Code | 28051990 |
| Hazardous Substances Data | 7440-46-2(Hazardous Substances Data) |
| Excepted Quantities | Not Permitted as Excepted Quantity |
