cesium
Cesium
CAS: 7440-46-2
Molecular Formula: Cs
cesium - Names and Identifiers
| Name | Cesium |
| Synonyms | Cesium caesium CESIUM STANDARD SOLUTION 100 ML Cesiumbreaksealampouleunderargon Cesiumprescoredampouleunderargon Cesium Metal in breakseal ampoule CESIUM ICP STANDARD TRACEABLE TO SRM FRO |
| CAS | 7440-46-2 |
| EINECS | 231-155-4 |
| InChI | InChI=1/Cs |
cesium - Physico-chemical Properties
| Molecular Formula | Cs |
| Molar Mass | 132.91 |
| Density | 1.873 g/mL at 25 °C (lit.) |
| Melting Point | 28.5 °C (lit.) |
| Boling Point | 705 °C (lit.) |
| Water Solubility | reacts with H2O to evolve H2; soluble liquid NH3 [MER06] |
| Solubility | H2O: soluble |
| Vapor Presure | 1 mm Hg ( 279 °C) |
| Appearance | ingot |
| Specific Gravity | 1.892 |
| Color | Silver |
| Exposure Limit | ACGIH: TWA 2 ppm; STEL 4 ppmOSHA: TWA 2 ppm(5 mg/m3)NIOSH: IDLH 25 ppm; TWA 2 ppm(5 mg/m3); STEL 4 ppm(10 mg/m3) |
| Merck | 13,2018 |
| Storage Condition | 2-8°C |
| Stability | Flammable solid; highly flammable in powder form. Moisture-sensitive. Incompatible with chlorine, phosphorus, water. |
| Sensitive | moisture sensitive |
| Physical and Chemical Properties | A silver-white ductile metal. Relative density 1.892(18 degrees C). Melting point 28.44 °c. Boiling point 671 °c. Rapid oxidation in humid air, can spontaneous ignition. Hardness 0.2 Mohs. Resistivity (0 ℃)19 μ Ω? cm,(30℃)36.6μΩ? cm. Specific heat capacity (20 degrees C) 0.217 J/(g? K). Heat of fusion: 2.087kJ/mol; Heat of vaporization: 68.85 kJ/mol. Thermal conductivity: 35.9W/(m? K), at the melting point of the liquid is 18.4w/(m? K), at the boiling point of the vapor is 0.0046w/(m? K). Reaction with water to release H2, soluble in liquid ammonia. It is second only to Mercury as a fusible metal. The properties of cesium are similar to potassium, but more reactive than potassium (the most active of the alkali metals). In contact with air, there is a fire, and an explosive reaction occurs when organic matter is mixed. Intense reaction with water or acids releases H2 for combustion. Have severe reactivity, sometimes explosive |
| Use | Widely used in the electronics industry, glass-ceramic industry, pharmaceutical and metallurgical industries |
cesium - Risk and Safety
| Risk Codes | R36/38 - Irritating to eyes and skin. R34 - Causes burns R14/15 - R11 - Highly Flammable |
| Safety Description | S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S45 - In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) S43 - In case of fire use ... (there follows the type of fire-fighting equipment to be used.) S36/37/39 - Wear suitable protective clothing, gloves and eye/face protection. S16 - Keep away from sources of ignition. S8 - Keep container dry. |
| UN IDs | UN 3264 8/PG 3 |
| WGK Germany | 3 |
| RTECS | FK9225000 |
| FLUKA BRAND F CODES | 10 |
| TSCA | Yes |
| HS Code | 28051990 |
| Hazard Class | 4.3 |
| Packing Group | I |
cesium - Reference Information
| resistivity | 19 ++-cm, 0°C |
| EPA chemical substance information | information provided by: ofmpeb.epa.gov (external link) |
| Overview | cesium, atomic weight 132.90545(2). Atomic number 55. Silver-white hexagonal metal (the clean surface of the simple substance is golden yellow). Light, soft and extendable. The melting point is 28.55±0.16 ℃, the boiling point is 669.5 ℃, and the relative density is 1.873. Among the alkali metals, it is the most electropositive strong basic element. An explosion occurred in reaction with cold water. At -116 °c, it can still react with water. Soluble in liquid ammonia, the formation of amino compounds and hydrogen. It can directly react with halogen, phosphorus and sulfur to generate corresponding binary compounds. It is found in cesium-aragonite, carnallite and scaly Mica. Obtained by electrolytic melting of cesium chloride. Very pure gaseous cesium can be obtained from the thermal decomposition of cesium azide. Cesium is mainly used in the manufacture of photoelectric tube, spectrograph, scintillation counter, electron tube, infrared signal lamp, and optical automatic control instrument, and also used for oxygen absorber of electron tube. Cesium salts are used as medicines in medical treatment. The isotope cesium -137, used to treat cancer. 1860 German chemist Benson (R.Bunsen) and Kirchhoff (G.R.Kirchoff) found Cesium in the study of the spectrum of mineral water, which is the first element found by spectroscopy, according to the color of its spectral lines in Latin Caesius (Sky Blue) named cecum (Cesium). Cesium metal was first produced in 1881 by C.Setterberg when the cesium cyanide-barium cyanide mixed molten salt was electrolyzed. Cesium has not been used in industry for more than 60 years after its preparation. The photoelectric cell was made of cesium in 326, but the amount was very small. Before the First World War only Germany produced a small amount of cesium, only a few kilograms. Cesium production began in the United States in the 1930s. During the Second World War, cesium as a photosensitive material, the amount of increase, but because of the high price of cesium and rare, the application is limited. In, the United States successfully studied the method of recovering cesium and rubidium from the mother liquor of lithium extraction from Lepidolite, mixed carbonate alkali solution (containing Cs2O2% and Rb2O 23%), which led to a sudden increase in cesium production. Cesium as a by-product of lithium production, the cost is low, the price also decreased significantly, which greatly promoted the application of cesium and the study of cesium properties. Since the 60s of the 20th century, cesium has been applied in atomic clocks, optical instruments, lasers, organic synthesis and so on. At the same time, a variety of methods for extracting cesium have been developed, which makes the extraction and metallurgy technology of cesium reach a considerable level, product quality continues to improve, the price further decline. China began its research on the smelting of cesium in 1956, In the early 60 s, cesium was produced, and cesium resources in Xinjiang, Jiangxi, Sichuan and other provinces have been developed. Now more than 20 kinds of cesium and rubidium products can be produced, to meet the needs of domestic economic development and scientific research on cesium. |
| physical properties | cesium metal is a body-centered cubic crystal structure, soft and ductile, which can be cut by knife. The configuration of the outer electron layer of the cesium atom is [Xe]6 S1. In the alkali metal, cesium has the lowest melting point and boiling point, the highest vapor pressure, the highest density, the best thermal conductivity and conductivity, and the lowest ionization potential. There are 22 kinds of isotopes of cesium, and its mass number is between 123 and 144. 133Cs is a stable isotope in nature. Radioisotope 137Cs is the fusion product of an atomic reactor with a half-life of 30.23a. (2015-11-16) |
| Chemical properties | cesium has all the chemical characteristics of alkali metals, and is the most active element in alkali metal chemical reaction. The common cesium valence is positive monovalent, and the reduction potential of Cs → Cs0 is -2.923V. Cesium and rubidium are similar in nature and difficult to separate. When the metal cesium burns in the air, it sputters thick alkaline smoke, which can harm the eyes, respiratory system and skin. The oxidation of cesium in moist air gives off sufficient heat to cause the cesium to ignite and melt. Cesium and oxygen react vigorously to form a mixture of various oxides. Cesium has two oxidation states, Cs-1(s2) and Cs. The interaction of cesium and water will be a strong explosion, even with the 157K temperature of the ice contact is also a sharp reaction, the formation of hydroxide, the release of hydrogen. Unlike lithium, cesium does not react with nitrogen. Cesium reacts with hydrogen at high temperatures to produce a fairly stable hydride. Cesium and acetylene react to form ethynides. The vigorous reaction of cesium and halogen is different from the reaction of other alkali metals with halogen. Cesium can form stable polyhalides, such as csi3. Cesium reacts with ammonia to form amino-cesium (CsNH2). At low temperatures, cesium reacts with CO to form a crystalline compound of variable composition. Cesium carbonate can be reduced by metal magnesium to metal cesium, and cesium chloride can be reduced by calcium. Cesium and other alkali metals can form liquid alloys with low melting points, such as Cs-12Na-47K alloy, which has a melting point of Cs-55Na K;Cs ~ 13Rb alloy, which has a melting point of K; And alloy, which has a melting point of K. Cesium salts can produce alum, such as CsCl · SbCl3, which is very difficult to dissolve. Smelting on the use of cesium alum insoluble characteristics to separate cesium, analysis for quantitative determination of cesium content. |
| resources and mineral raw materials | The crustal abundance of cesium is lithium, sodium, potassium, rubidium, cesium five alkali metal elements in the smallest, 2.6 x 10-4%, seawater containing 5 x 10-8% cesium. Cesium is normally symbiotic with lithium, rubidium, and potassium. Although cesium is much less abundant than rubidium in the crust, there are industrial independent minerals for cesium. Lepidolite is one of the main resources for the extraction of cesium. Some Lepidolite minerals contain high cesium. For example, the Lepidolite mineral in California, USA contains CszOO.30%, and the lepidolite in Kola Peninsula of the former Soviet Union contains Cs20 O.24%. The Lepidolite reserves in Zimbabwe are larger than those in the Kita region, but contain only cs. OO.08%. Cesium aragonite is an important industrial resource of cesium, which is mainly produced in the United States, the United States, the bernicke Lake, Canada, Zimbabwe, the bikitta region and Namibia. In addition, there are a small number of Swedish, mozambique and East Kazakhstan. General cesium-aragonite containing cesium is very high, containing lithium, rubidium is low, and some even contain very little rubidium. For example, the cesium aragonite in the United States of America contains Csz0 36% and Li20 0.04%, the cesium aragonite in the Kola Peninsula of the former Soviet Union contains Cs20 27.1%, and the cesium aragonite in the Italian island of Elba contains Cs:O 34%(Liz0 trace). Cs content of cesium aragonite in Xinjiang, China: 0 29% ~ 30%. Almost none of the above minerals contain rubidium. In addition, the cesium aragonite in Lake bernicke, Canada contains Cs20 28.6%, Rb20 1.36%, Li20 O.31%; Cesium aragonite in biketa, Zimbabwe contains Cs20 22.4%, Rb20O.84%, Li20 O.30%. Carnallite is also an important source of cesium, mainly produced in Germany. The former Soviet Union Kola Peninsula has the world's largest carnallite producing area. Salt lakes, underground brine, gas field water, oil well water, hot spring water and geothermal water contain a large amount of cesium, and some contain relatively high amounts of cesium. For example, the lake water of Salton in the United States contains cszO(16~21)× 10-'%, and the oilfield water of Wood Lake contains Csa0 25 × 10-'%. The total cesium reserves identified in the world are 120000T, of which 80000T in Canada, 25000T in Zimbabwe and 10000t in Namibia. China is rich in cesium resources, mainly distributed in the Yichun of Jiangxi, Xinjiang's hoto sea, Sichuan's Kangding, Hunan's xianghualing and Qinghai. Lepidolite in Jiangxi contains Cs20 0.3% and Rb. 0 1.72%, is the largest cesium resource base in China. China's salt lake brine, rich in cesium resources, the average content of cs in the Tibetan plateau brine. 0 0.03g/L, the cesium in Zigong brine in Sichuan has also been developed and utilized. |
| preparation method | cesium aragonite is calcined with calcium oxide and calcium chloride to obtain cesium chloride, which is then fused and electrolyzed, cesium metal can be obtained. 2CsAlSi2O6 3CaO CaCl2→ 2CsCl Al2O3 4CaSiO3 2CsCl→2Cs Cl2 |
| extraction metallurgy | mainly includes cesium extraction (preparation of compounds) and cesium metal preparation two major steps. Sometimes in order to obtain high purity cesium metal products, need for high purity cesium metal preparation. Cesium extraction is the process of extracting cesium compounds from cesium raw materials such as Lepidolite, cesium aragonite and carnallite. Cesium-aragonite extraction of cesium, rubidium cesium aragonite hydrochloric acid decomposition, cesium aragonite sulfuric acid decomposition, alkali molten salt roasting, chlorination roasting and ore direct reduction method. The first two methods are mainly used in industry. Cesium compounds extracted from cesium raw materials often contain a certain amount of impurities, and pure cesium compounds need to be prepared by methods such as solvent extraction and cesium extraction. |
| uses | cesium and its compounds are mainly used in the research and development of high technology, such as magnetic fluid power generation, Thermionic power generation, turbine power generation and ion propulsion technology research and development, these technologies are in the development stage. The amount of cesium used in high technology in the United States accounts for 50% ~ 70% of the total amount of cesium. Industrial applications of cesium are mainly in the electronics industry, glass-ceramics, and pharmaceuticals. The properties of cesium and its compounds are similar to rubidium, and they can be substituted mutually in many applications, but some properties of cesium are better than rubidium, for example, the photoelectric conversion sensitivity of cesium is higher than that of rubidium. Magnetic Fluid Power generation is the high temperature conductive flow generated by various fuels through a strong magnetic field, which is directly converted into electrical energy by thermal energy under the action of electrical induction. Cesium is added to the fuel as an inducing material, the temperature required for fuel ionization can be reduced, the ionic flame conductivity can be improved, and the energy generated can be increased. Approximately 3000t Caesium carbonate is required per year for a 600,000 magnetic current-steam combined power plant. The thermoelectric transducer is a diode that generates a large current output by using the phenomenon of thermal electron emission, and the thermal energy is directly converted into electric energy. The diode made of cesium can improve the power generation efficiency of the thermionic generator. After ionized, the vaporized metal cesium can be accelerated to near the speed of light under the action of an electric field, and then neutralized by the electron beam and ejected from the engine, which can produce a powerful driving force. The specific impulse of rocket engine with cesium propellant can reach 2000s (the specific impulse of most chemical fuels is only 300 ~ 400s). The range of an ion-propelled spacecraft with 150g of cesium is about times that of commonly used fuel ships. The energy of ordinary light is enough to make cesium free-bid electrons. This characteristic of cesium is used in the manufacture of phototubes, spectrographs, Radio Electron Tubes, military infrared signal lamps and various optical instruments and testing instruments, the use of cesium photovoltaic power supply to find the target guide warhead, can track, intercept the enemy's flying objects. Low-voltage electron beam camera tubes made of cesium cathodes are used in television technology. Cesium halides have luminescent properties and are used in the fabrication of scintillation counters. Sodium-activated cesium iodide is much more resistant to X-rays than other halides, and the image intensifier made of sodium iodide has high resolution, strength and stability, the medical X-ray machine can be observed by many people without the use of a darkroom without the use of X-ray radiation. Many countries use a cesium atomic clock as the frequency and time standard, Its accuracy reaches 1 × 10-13S, which is widely used in communication, transportation, military and aerospace industries. Cesium nitrate is a photorefractive modifier for multi-component special glasses and is widely used in the production of optical fibers and fibrous lenses. Cesium has high chemical activity and low ionization potential, which can change the surface properties of the main catalyst. The catalyst containing cesium has better catalytic activity, selectivity and stability, which can prolong the service life of the catalyst, to prevent poisoning of the catalyst. Cesium-containing catalysts are widely used in ammonia synthesis, sulfuric acid production and organic matter oxidation, hydrogenation, polymerization, nitrile formation and other organic synthesis. Cesium salt has a sedative effect, can be used in the manufacture of sleeping pills, sedatives, epilepsy treatment. 137Cs is used as a radioisotope marker to diagnose tumors and is replacing 60Co in the treatment of cancer. Caesium chloride is used as a density-gradient medium for the separation of Virus, destilin-ribonucleic acid and other macromolecules by ultracentrifugation. Cesium is used as a degassing agent and refining agent in the metallurgical industry. photoelectric element. Catalysts for polymerization. Infrared lamp. Atomic clock. widely used in the electronics industry, glass-ceramic industry, pharmaceutical and metallurgical industry is an important material for the manufacture of vacuum devices, Phototubes and other chemical catalysts. |
| toxicity | can easily cause fire. Contact with the humid air ignition, and the oxygen in the air reaction to form superoxide, when mixed with organic matter, produce explosive reaction. Contact with water or acid reacts vigorously and releases hydrogen to cause combustion. Contact with halogen, sulfur and oxidant reacts vigorously. The toxicity is stronger than sodium, but there are no cases of poisoning caused by cesium. Cesium mainly on the eyes, skin and mucous membranes have strong irritation and corrosive. Rat abdominal LD50:89 mg/kg. When Burns occur, immediately rinse with water, clean the wound, and send to hospital for treatment. |
| production method | vacuum distillation purification the device is first pumped to a vacuum with a diffusion pump, the whole apparatus was heated from A to E to 400-450 °c and allowed to dry for several hours. Then, the purified argon gas is filled into the whole device, the Part A is cut open, and the container containing the metal cesium with the volatile oil is sent to the tube B. After the volatile oil is evaporated, the tube B is sealed again, the apparatus was evacuated (≤ 10-6 Torr), and heated in the vicinity of E in an electric furnace to precipitate cesium by distillation in tube D. Fig. By rotating the device, molten cesium flows from tube D into the ampoule. After cooling, the device is filled with argon, and the ampoule melt is cut off to obtain high purity cesium. |
| category | water burning articles |
| toxicity grade | poisoning |
| Acute toxicity | intraperitoneal-mouse LD50: 1700 mg/kg |
| explosive hazard characteristics | explosion of hydrogen emitted by water, moist air and oxidant |
| flammability hazard characteristics | when water or moist air emits hydrogen |
| storage and transportation characteristics | The warehouse is ventilated and dried at low temperature; It is not stored in hydrocarbons; It is mixed with oxidants, halogens, strong acid stored separately |
| extinguishing agent | dry powder, dry sand, dry powder |
| toxic substance data | information provided by: pubchem.ncbi.nlm.nih.gov (external link) |
Last Update：2024-09-05 07:59:09
