Name | barium |
Synonyms | bario barium Barium BARIUM STICKS UNDER PARAFFIN OIL |
CAS | 7440-39-3 |
EINECS | 231-149-1 |
InChI | InChI=1/Ba.2H/rBaH2/h1H2 |
Molecular Formula | Ba |
Molar Mass | 137.33 |
Density | 3.6g/mLat 25°C(lit.) |
Melting Point | 725°C(lit.) |
Boling Point | 1640°C(lit.) |
Water Solubility | soluble with H2 evolution in cold H2O and hot H2O; slightly soluble alcohol; insoluble benzene [CRC10] |
Appearance | rod |
Specific Gravity | 3.51 |
Color | Silver-gray |
Exposure Limit | TLV-TWA 0.5 mg/m3 (for soluble compounds)(ACGIH and MSHA); IDLH (forsoluble compounds) 250 mg/m3 (NIOSH).. |
Merck | 13,967 |
Storage Condition | water-free area |
Stability | Stability Reacts vigorously or violently with acids, water, tetrachloromethane, small halogenated hydrocarbons. Should be stored under an inert material such as petroleum ether to exclude air. Flammab |
Sensitive | air sensitive, moisture sensitive |
Physical and Chemical Properties | The phase is a group II main group (alkaline earth metal) element. Atomic number 56. Stable Isotopes: 130,132,134,135,136,137,138. Atomic Weight 137.327. Silver-white metal. Slightly glossy. Density 3.76. Melting point 710 °c. The boiling point is about 1600 °c. Valence 2. The chemical nature is quite active, easy to oxidize, should be stored in the oil. Can decompose water to generate hydroxide and hydrogen. Combustion in oxygen at high temperatures produces barium peroxide (BaO2). Soluble in acid and salt formation. Barium Salt in addition to barium sulfate are toxic! |
Use | Used in the preparation of barium salt, alloy, fireworks, nuclear reactor, etc., is also an excellent oxygen scavenger when refining copper. |
Risk Codes | R25 - Toxic if swallowed R26 - Very Toxic by inhalation R34 - Causes burns R36/37/38 - Irritating to eyes, respiratory system and skin. R14/15 - R11 - Highly Flammable |
Safety Description | S23 - Do not breathe vapour. S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S36 - Wear suitable protective clothing. S36/37/39 - Wear suitable protective clothing, gloves and eye/face protection. 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 - Wear suitable protective clothing and gloves. S16 - Keep away from sources of ignition. |
UN IDs | UN 3264 8/PG 3 |
WGK Germany | 3 |
RTECS | CQ8370000 |
TSCA | Yes |
HS Code | 2805 19 10 |
Hazard Class | 8 |
Packing Group | III |
Toxicity | An element; the heaviestof the stable alkaline earths. Barium sulfate is used as adiagnostic aid in radiology due to its radio-opaqueness and,because of its insolubility and lack of absorption, it is safe barringiatrogenic episodes. Poisoning usually results from deliberateor accidental ingestion of soluble barium compounds.The Ba2+ ion is a muscle poison due to the blocking of the K1channels of the Na+/K+ pump in cell membranes. Becausecases of barium poisoning are accompanied by severe hypokalemia,potassium infusion is an effective antidote. The toxicityof barium compounds depends on their solubility, with the freeion being readily absorbed from gastrointestinal tract or lung,whereas the sulfate is essentially unabsorbed. Thus, administrationof soluble sulfates immediately after ingestion isanother effective antidote. |
Raw Materials | Barium chloride |
Introduction | element Ba; Atomic number 56; Atomic weight 137.327; Group IIA (group 2) alkaline earth element. Barium is a silver-white metal. In nature it is found only in ores containing a mixture of elements. Important combinations are peroxides, chlorides, sulfates, carbonates, nitrates and chlorates. Barium forms alloys and intermetallic compounds with lead, potassium, platinum, magnesium, silicon, zinc, aluminum and Mercury. Barium compounds show a close relationship with calcium and strontium compounds which are also alkaline earth metals. 25 kinds of Barium isotopes have been identified, of which 138Ba is the most abundant, and the rest are unstable isotopes, and the Half-Life is from 12.8 days of 140Ba to 12 s of 143Ba. Two of these isotopes, 131Ba and 139Ba, were used as radiotracers in the study. |
History of discovery | at the beginning of the Middle Ages, aldrans had some knowledge of barium ores. Some of the smoothed, gravel-like barite stones, known as the "pomade", found in Italy, have been noticed by aldrans because these minerals light up for years after exposure to light. In 1602, V. Casciorolone described this property of phosphorescence from heating barite with organic matter. In 1774, Karl William Scheler discovered that barite contained a new element that was not found, but it was impossible to separate and purify this element. Only its oxide, barium oxide, was obtained. Two years later, the barium oxide was obtained in the same study, by John goldbb Gann. Barium oxide was first referred to as "barote" by Guiton de Morveau and was later referred to as "baryta" by lavasite ". Also in the 18th century, British mineralogist William willinn noticed a heavy mineral, now known as Witherite, in the lead mine in Chamberland, whose main component is barium carbonate. In 1808, hanfrei David first separated barium simple substance by electrolysis of molten barium salt. David named barium (balium) by a method similar to calcium, using the name of barite (baryta) plus the suffix-ium representing the element. Robert Benson and sulstus mathosen obtain pure barium by electrolysis of a molten mixture of barium chloride and ammonium chloride. |
Source | barium is the 17th most abundant element in the crust, accounting for about 0.05% of the crust. It is found in Magnesia ores, which are barium carbonate (BaCO3) and barite, known as barium sulfate (BaSO4). Pure barium metal is not present on Earth, only in the form of compounds or in minerals and ores. Barium ores were found in Missouri, ar, Georgia, Kentucky, Nevada, California, Canada, and Mexico, which were made by reduction of barium oxide (BaO) using aluminum or silicon under high temperature vacuum. It is also produced by electrolytic melting of barium chloride (BaCl2) at a temperature of about 950 °c, where the barium metal is collected at the cathode and the chlorine gas is discharged at the anode. |
Application | The most important use of barium is as a scavenger in tubes. This metal is typically in powder form or alloyed with aluminum for removal of the last trace gases in vacuum and television tubes. Barium alloys have many applications. It is incorporated into the lead alloy mesh of the acid battery to achieve better performance; And is added to the molten steel and metal in the deoxygenated alloy to reduce the oxygen content. Barium films are used as lubricants and are suitable for use at high temperatures on anode rotors in vacuum X-ray tubes and on alloys for spark plugs. Several radioactive isotopes of this element can be used in nuclear reactions and spectroscopy. |
preparation | the mined ore needs to be washed, crushed, classified, and separated from quartz. If the penetration of quartz into the ore is too deep, or if the iron, zinc and lead content in the ore is too high, the foam flotation process must be used. The final product is barite with mass fraction of 98%, purity of not less than 95%, and the content of iron and silica is very small. Subsequent reduction of barium sulfate with carbon: BaSO4 +2 C → BaS +2 co2↑ after the formation of water-soluble barium sulfide, it can be used as a raw material for other products: reaction with oxygen to obtain barium sulfate, and nitric acid to produce barium nitrate, and carbon dioxide to produce barium carbonate. Barium nitrate can be decomposed by heating to produce barium oxide. Barium metal can be obtained by reacting barium oxide with aluminum at 100 ° C. (° F.). The intermetallic compound BaAl4:3 BaO +14 Al → 3 BaAl4 + Al2O3BaAl4 is an intermediate product that reacts with barium oxide to form a metal. Note that not all of the barium element is reduced. 8 BaO + BaAl4 → Ba ++ 7 BaAl2O4 the remaining barium oxide reacts with the generated alumina: BaO + Al2O3 → BaAl2O4 the total reaction is: 4 BaO +2 Al → 3 Ba ++ BaAl2O4 barium vapor was condensed in an argon atmosphere and loaded into a mold. This method is commercially used for the production of ultra-pure barium. Generally marketed barium is about 99% pure, with the major impurities being strontium and calcium (up to 0.8% and 0.25%), while the other impurity components are less than 0.1%. A similar reaction of barium sulfate with silicon at 200 ° C. (190 ° F.) can also occur to obtain barium and barium metasilicate. However, electrolysis is not generally used in industry because barium is readily soluble in molten halides and the product is of low purity. |
hazard | barium metal in powder form is flammable at room temperature. It must be stored in an oxygen-free atmosphere or in oil. Many compounds of barium are toxic, especially barium chloride, which can affect heart function, cause ventricular fibrillation, arrhythmia, and even lead to death. Several barium compounds are explosive and toxic if ingested or inhaled. Care should be exercised when using barium and other alkali metals in the laboratory or industry. |
toxicity | dust is prone to spontaneous combustion at room temperature. Ignition and explosion can be caused by exposure to heat, flame or chemical reaction. It is easy to decompose in water and react with acids to release hydrogen, which can be caused by the heat of reaction. Barium metal is generated in water, barium hydroxide, corrosion, and water-soluble barium salt has great toxicity. Accidental ingestion or inhalation of dust can cause poisoning. Patients should be separated from the contaminated area and placed to rest and keep warm. The patient was given a large amount of water to flush his eyes. Skin contact first rinse with water, then wash thoroughly with soap, if there is a burn treatment. Gargle immediately. The patient was sent to the hospital for emergency treatment. |
Chemical properties | yellow-silver-white soft metal. The relative density was 3.62. Melting point 729 °c. Boiling point 1640 °c. Body-centered cubic: α = 0.5025 nm. Heat of fusion: 7.66 kJ/mol; Heat of vaporization: 149.20 kJ/mol. Vapor pressure: 0.00133 kPa(629 °c),1.33 kPa(1050 °c),101.3 kPa(1640 °c). Resistivity: 29.4 μΩ? cm. Electronegativity 1.02.: Ba2 radius 0.143 nm. Thermal conductivity 18.4(25 degrees C) w/(m? K). Coefficient of thermal expansion: linear expansion coefficient 1.85 × 10-5m/(m? C). It is easy to react with water at room temperature to release hydrogen, which is slightly soluble in alcohol and insoluble in benzene. |
Application | is widely used in alloys, such as lead, calcium, magnesium, sodium, lithium, aluminum and nickel. For the removal of residual trace gases in the radio vacuum tube. It is used for making barium salt, alloy, fireworks, nuclear reactor, etc. It is also an excellent oxygen scavenger for refining copper. |
production method | barium oxide is prepared by thermal decomposition of barium nitrate by aluminothermic reduction method, using fine-grained aluminum as reducing agent, and the ratio of ingredients is 3BaO:2Al, the barium oxide and aluminum were first made into a pellet, the pellet was charged into a distillation apparatus, and the reduction distillation was carried out by heating to 1150 ° C. To obtain a barium purity of 99%. |
category | flammable articles in water |
toxicity grade | highly toxic |
Acute toxicity | oral-dog LDL0: 1 mg/kg (reference: barium metal) |
explosive hazard characteristics | explosive in water |
flammability hazard characteristics | spontaneous combustion in air; Flammable in water; Flammable hydrogen in water, alcohol and acid; water and acid soluble barium salt poisoning |
storage and transportation characteristics | The warehouse is ventilated and dried at low temperature; It is stored separately from acid, oxidant and halogenated hydrocarbon |
extinguishing agent | graphite powder, dry sand |
Occupational Standard | TWA 0.5 mg (barium)/m3 |
EPA chemical substance information | information provided by: ofmpeb.epa.gov (external link) |
toxic substance data | information provided by: pubchem.ncbi.nlm.nih.gov (external link) |
immediate life-threatening and health concentration | 50 mg Ba/m3 |