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| Product Name: | Barium | | Synonyms: | bario;BARIUM, DISTILLED, DENDRITIC PIECES, 99. 99%;Barium, rods, ~2cm diam., 99+% metals basis;BARIUM, DENDRITIC PIECES, 99.9%;BARIUM, GRANULES, UNDER OIL, 99%;BARIUM DISTILLED DENDRITIC PIECES &;BARIUM PIECES 99%;BARIUM STICKS UNDER PARAFFIN OIL | | CAS: | 7440-39-3 | | MF: | Ba | | MW: | 137.33 | | EINECS: | 231-149-1 | | Product Categories: | Alkali MetalsMetal and Ceramic Science;Barium;Metals;Reduction;Synthetic Reagents;AA Standard SolutionsAlphabetic;AAS;B;BA - BHSpectroscopy;ChlorideSpectroscopy;Matrix Selection;Reference/Calibration Standards;Single Solution;Standard Solutions;metal or element;Inorganics | | Mol File: | 7440-39-3.mol |  |
| | Barium Chemical Properties |
| Melting point | 725 °C(lit.) | | Boiling point | 1640 °C(lit.) | | density | 3.6 g/mL at 25 °C(lit.) | | storage temp. | water-free area | | form | rod | | Specific Gravity | 3.51 | | color | Silver-gray | | resistivity | 50.0 μΩ-cm, 20°C | | Water Solubility | soluble with H2 evolution in cold H2O and hot H2O; slightly soluble alcohol; insoluble benzene [CRC10] | | Sensitive | air sensitive, moisture sensitive | | Merck | 13,967 | | Exposure limits | TLV-TWA 0.5 mg/m3 (for soluble compounds)
(ACGIH and MSHA); IDLH (for
soluble compounds) 250 mg/m3 (NIOSH).
. | | 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. Flammable. | | CAS DataBase Reference | 7440-39-3(CAS DataBase Reference) | | EPA Substance Registry System | Barium (7440-39-3) |
| Hazard Codes | C,Xi,F | | Risk Statements | 25-26-34-36/37/38-14/15-11 | | Safety Statements | 23-26-36-36/37/39-45-43-36/37-16 | | RIDADR | UN 3264 8/PG 3 | | WGK Germany | 3 | | RTECS | CQ8370000 | | TSCA | Yes | | HS Code | 2805 19 10 | | HazardClass | 8 | | PackingGroup | III | | Hazardous Substances Data | 7440-39-3(Hazardous Substances Data) | | Toxicity | An element; the heaviest
of the stable alkaline earths. Barium sulfate is used as a
diagnostic aid in radiology due to its radio-opaqueness and,
because of its insolubility and lack of absorption, it is safe barring
iatrogenic episodes. Poisoning usually results from deliberate
or accidental ingestion of soluble barium compounds.
The Ba2+ ion is a muscle poison due to the blocking of the K1
channels of the Na+/K+ pump in cell membranes. Because
cases of barium poisoning are accompanied by severe hypokalemia,
potassium infusion is an effective antidote. The toxicity
of barium compounds depends on their solubility, with the free
ion being readily absorbed from gastrointestinal tract or lung,
whereas the sulfate is essentially unabsorbed. Thus, administration
of soluble sulfates immediately after ingestion is
another effective antidote. | | IDLA | 50 mg Ba/m3 |
| | Barium Usage And Synthesis |
| Chemical Properties | Barium has the symbol Ba, atomic number 56, and is the fifth element in Group 2. Its atomic weight is 137.332 g/mol. Barium is a soft silvery metal. It is never found in nature in its pure form due to its reactivity with air. Its oxide is historically known as “Baryta” but because it reacts with water and carbon dioxide, it is not found as a mineral. The most common naturally occurring minerals are the very insoluble barium sulfate, BaSO4 (Barite), and barium carbonate, BaCO3 (Witherite). Barium s name originates from the Greek word bary , meaning heavy , describing the high density of some common barium-containing ores. Alchemists in the early Middle Ages knew about some barium minerals. Smooth pebble-like stones of mineral Baryte found in Bolona, Italy were known as Bologna Stones . After exposed to light, they would glow for years (probably because they contained some barium sulfide (BaS) formed during the calcination of the stone with charcoal carbon). It was this quality that attracted them to witches and alchemists.
Though barium minerals are dense, barium metal itself is comparatively light. Its cosmic abundance is estimated as 3.7 atoms (on the same basis, Si=106 atoms). Barium constitutes about 0.03% of the Earth s crust, chiefly as the minerals Barite (also called barytes or heavy spar) and Witherite . The abundance of barium is 0.0425% in the Earth s crust and 13 mg/l in seawater. A rare gem containing barium is known, called Benitoite (BaTiSi3O9). Large deposits of Barite are found in China, Germany, India, Morocco, and in the US. Because barium quickly oxidizes in air, it is difficult to obtain the free metal and it is never found free in nature. Barium is a soft and ductile metal. Its simple compounds are notable for their relatively high specific gravity (as compared to the other alkaline earth elements). Barium, which is slightly harder than lead, has a silvery white luster when freshly cut. | | Defination | Symbol Ba; atomic number 56; atomic weight 137.327; a Group IIA (Group 2) alkaline earth element; electronic configuration [Xe]s2; valence state +2; ionic radius of Ba2+ in crystal (corresponding to coordination number 8) 1.42 Å; first ionization potential 10.00eV; stable isotopes and their percent abundances: Ba–138 (71.70), Ba–137 (11.23), Ba–136 (7.85), Ba–135 (6.59), Ba–134 (2.42); minor isotopes: Ba–130 (0.106) and Ba–132 (0.101); also twenty-two radioisotopes are known.
| | Occurrence | Barium was discovered in 1808 by Sir Humphrey Davy. Its abundance in the earth’s crust is about 0.0425% (425 mg/kg). The element also is found in sea water at trace concentration, 13 μg/L. It occurs in the minerals barite or heavy spar (as sulfate) and witherite (as carbonate).
| | Uses | The most important use of barium is as a scavenger in electronic tubes. The metal, often in powder form or as an alloy with aluminum, is employed to remove the last traces of gases from vacuum and television picture tubes. Alloys of barium have numerous applications. It is incorporated to lead alloy grids of acid batteries for better performance; and added to molten steel and metals in deoxidizing alloys to lower the oxygen content. Thin films of barium are used as lubricant suitable at high temperatures on the rotors of anodes in vacuum X-ray tubes and on alloys used for spark plugs. A few radioactive isotopes of this element find applications in nuclear reactions and spectrometry.
| | Description | Barium is a silvery-white metal. It exists in nature only in ores containing mixtures of elements.
The important combinations are the peroxide, chloride, sulphate, carbonate, nitrate,
and chlorate. The pure metal oxidises readily and reacts with water emitting hydrogen. It
combines with other chemicals such as sulphur or carbon and oxygen to form barium compounds.
Barium compounds are used by the oil and gas industries to make drilling muds.
Barium attacks most metals with the formation of alloys; iron is the most resistant to alloy
formation. Barium forms alloys and intermetallic compounds with lead, potassium, platinum,
magnesium, silicon, zinc, aluminium, and mercury. Barium compounds exhibit close
relationships with the compounds of calcium and strontium, which are also alkaline earth
metals. Twenty-five barium isotopes have been identified, 138Ba being the most abundant,
and the others are unstable isotopes with half-lives ranging from 12.8 days for 140Ba to 12 s
for 143Ba. Two of these isotopes, 131Ba and 139Ba, are used in research as radioactive tracers.
The general population is exposed to barium through air, drinking water, and food. | | Chemical Properties | Barium is a silvery-white metal. It exists in nature only in ores containing mixtures of elements. The important combinations are peroxide, chloride, sulfate, carbonate, nitrate, and chlorate. The pure metal oxidizes readily and reacts with water, emitting hydrogen. It com- bines with other chemicals such as sulfur or carbon and oxygen to form barium compounds. Barium compounds are used by the oil and gas industries to make drilling muds. Barium attacks most metals with the formation of alloys; iron is the most resistant to alloy formation. Barium forms alloys and intermetallic compounds with lead, potassium, platinum, mag- nesium, silicon, zinc, aluminum, and mercury. Barium compounds exhibit close relation- ships with the compounds of calcium and strontium, which are also alkaline earth metals. Doctors sometimes use barium sulfate to perform medical tests and to take x-rays of the gastrointestinal tract. Twenty-i ve barium isotopes have been identii ed. 138Ba is the most abundant; the others are unstable isotopes with half-lives ranging from 12.8 days for 140Ba to 12 sec for 143Ba. Two of these isotopes, 131Ba and 139Ba, are used in research as radioactive tracers. The general population is exposed to barium through air, drinking water, and food.
| | Physical properties | Barium is the fifth element in group 2 (IIA) of the alkali earth metals and has most of theproperties and characteristics of the other alkali earth metals in this group. For example, theyall are called alkaline earths because, when first discovered, they exhibited both characteristicsof alkaline (basic) substances and characteristics of the earth from which they came. Ancienthumans did not know they were metals because their metallic forms do not exist in nature.Barium is a silvery metal that is somewhat malleable and machineable (can be worked on alathe, stretched and pounded). Its melting point is 725°C, its boiling point is about 1640°C,and its density is 3.51 g/cm3. (The accurate figures for its properties are difficult to determinebecause of barium’s extreme activity—the pure metal will ignite when exposed to air, water,ammonia, oxygen, and the halogens. | | Isotopes | Naturally occurring barium is a mixture of seven stable isotopes: barium-138 (71.66%), barium-137 (11.32%), barium-136 (7.81%), barium-135 (6.59%), barium-134 (2.42%), barium-130 (0.101%), and barium- 132 (0.097%). About six times this many radioactive isotopes have been prepared with mass numbers ranging from 114 to 153. Of the 40 isotopes known, most are highly radioactive and have half-lives in the several milliseconds to a few days range. The only notable exceptions are 133Ba with a half-life of 10.51 years, 128Ba (2.43 days), 141Ba (11.50 days) and 140Ba (12.75 days). | | Origin of Name | The name barium is derived from the Latin word barys, which means
“heavy. | | Occurrence | Barium is the 17th most abundant element in the Earth’s crust, making up about 0.05%of the crust. It is found in the minerals witherite, which is barium carbonate (BaCO3), andbarite, known as barium sulfate (BaSO4). Pure barium metal does not exist on Earth—only ascompounds or in minerals and ores. Barium ores are found in Missouri, Arkansas, Georgia,Kentucky, Nevada, California, Canada, and Mexico.It is produced by the reduction of barium oxide (BaO), using aluminum or silicon ina high-temperature vacuum. It is also commercially produced by the electrolysis of moltenbarium chloride (BaCl2) at about 950oC, wherein the barium metal is collected at the cathodeand chlorine gas is emitted at the anode. | | Characteristics | When barium burns in air, it produces barium oxide (2Ba + O2 → 2BaO). When metallicbarium burns in water, it forms barium hydroxide [Ba + 2H2O → Ba(OH)2 + H2↑]. Severalbarium compounds burn with a bright green flame, which make them useful for fireworks.Barium is more reactive with water than are calcium and strontium. This is a result of thevalence electrons’ being further from the positive nucleus. Therefore, barium is more electronegative than the alkali earth metals with smaller nuclei.In powdered form, it will burst into a bright green flame at room temperature. | | History | Baryta was
distinguished from lime by Scheele in 1774; Barium was
discovered by Sir Humphrey Davy in 1808. It is found only in
combination with other elements, chiefly in barite or heavy
spar (sulfate) and witherite (carbonate) and is prepared by
electrolysis of the chloride. Large deposits of barite are found
in China, Germany, India, Morocco, and in the U.S. Barium
is a metallic element, soft, and when pure is silvery white like
lead; it belongs to the alkaline earth group, resembling calcium
chemically. The metal oxidizes very easily and should be
kept under petroleum or other suitable oxygen-free liquids to
exclude air. It is decomposed by water or alcohol. The metal is
used as a “getter” in vacuum tubes. The most important compounds
are the peroxide (BaO2), chloride, sulfate, carbonate,
nitrate, and chlorate. Lithopone, a pigment containing barium
sulfate and zinc sulfide, has good covering power, and does
not darken in the presence of sulfides. The sulfate, as permanent
white or blanc fixe, is also used in paint, in X-ray diagnostic
work, and in glassmaking. Barite is extensively used as
a weighting agent in oilwell drilling fluids, and also in making
rubber. The carbonate has been used as a rat poison, while
the nitrate and chlorate give green colors in pyrotechny. The
impure sulfide phosphoresces after exposure to the light. The
compounds and the metal are not expensive. Barium metal
(99.2 + % pure) costs about $3/g. All barium compounds that
are water or acid soluble are poisonous. Naturally occurring
barium is a mixture of seven stable isotopes. Thirty-six other
radioactive isotopes and isomers are known to exist. | | Uses | The element is used in metallurgy, and its compounds
in pyrotechnics, petroleum mining, and radiology.
Metallic barium has few industrial uses. It has been
historically used to scavenge air in vacuumtubes. There,
the metal is used as a getter in electron tubes to perfect
the vacuum by combining with final traces of gases. It
is also used as a deoxidizer in copper refining, and as
a constituent in certain alloys. The alloy with nickel
readily emits electrons when heated and, for this reason,
is used in electron tubes and in spark plug electrodes.
The presence of barium (atomic number 56), observed
after uranium (atomic number 92) had been bombarded
by neutrons, was the clue that led to the recognition of
nuclear fission (1939).
The most important use of elemental barium is as
a scavenger removing last traces of oxygen and other
gases in television and other electronic tubes. Additionally,
an isotope of barium, 133Ba, is routinely used as
a standard source in the calibration of gamma ray detectors
in nuclear physics studies. | | Uses | The element barium (Ba) has the atomic number 56 and is classified as a heavy metal. Barium metal is highly
reactive and therefore no elemental barium exists in nature. Natural sources of barium are the water-insoluble
minerals barite (barium sulfate) and whiterite (barium carbonate). In order to obtain pure barium compounds,
the mineral barite is reacted with carbon, and barium sulfide is formed. | | Uses | Pure barium metal has few commercial uses because of it reactivity with air and water.Nevertheless, this property makes it useful as a “getter” or scavenger to remove the last tracesof gas from vacuum tubes. Barium metal is used to form alloys with other metals. One alloy isused to make sparkplugs that easily emit electrons when heated, thus improving the efficiencyof internal combustion engines.Its compounds have many practical uses. For example, when the mineral barite is groundup into a fine powder, it can be used as a filler and brightener for writing and computer paper.It is also used (along with zinc sulfide) as a pigment, called lithopone, for white paint. Bariumcompounds are also used in the manufacture of plastics, rubber, resins, ceramics, rocket fuel,fireworks, insecticides, and fungicides and to refine vegetable oils.A major medical use is a solution of barium sulfide (with flavoring) that is ingested bypatients undergoing stomach and intestinal X-ray and CT scan examinations. Barium sulfideis opaque to X-rays, and thus it blocks the transmission of the rays. The organs appear in contrast against a background, which highlights any problems with the digestive system. | | Definition | barium: Symbol Ba. A silvery-whitereactive element belonging to group2 (formerly IIA) of the periodic table;a.n. 56; r.a.m. 137.34; r.d. 3.51; m.p.725°C; b.p. 1640°C. It occurs as theminerals barytes (BaSO4) andwitherite (BaCO3). Extraction is byhigh-temperature reduction of bariumoxide with aluminium or siliconin a vacuum, or by electrolysis offused barium chloride. The metal isused as a getter in vacuum systems.It oxidizes readily in air and reactswith ethanol and water. Soluble bariumcompounds are extremely poisonous.It was first identified in 1774 byKarl Scheele, and was extracted byHumphry Davy in 1808. | | Definition | A dense, low-melting
reactive metal; the fifth member of
group 2 (formerly IIA) of the periodic table
and a typical alkaline-earth element. The
electronic configuration is that of xenon
with two additional outer 6s electrons.
Barium is of low abundance; it is found as
witherite (BaCO3) and barytes (BaSO4).
The metal is obtained by the electrolysis of
the fused chloride using a cooled cathode
which is slowly withdrawn from the melt.
Because of its low melting point barium is
readily purified by vacuum distillation.
Barium metal is used as a ‘getter’, i.e., a
compound added to a system to seek out
the last traces of oxygen; and as an alloy
constituent for certain bearing metals.
Barium has a low ionization potential
and a large radius. It is therefore strongly
electropositive and its properties, and
those of its compounds, are very similar to
those of the other alkaline-earth elements
calcium and strontium. | | General Description | Barium alloy, pyrophoric is mixture of barium and other metals or nonmetallic elements to improve the specific usefulness of barium. Barium alloys are a solid and can ignite spontaneously in contact with air. Barium is toxic and products given off in fire could be very toxic. | | Air & Water Reactions | Finely divided metal powder is pyrophoric, ignites spontaneously in air [Bretherick 1979 p. 170-171]. Alloys containing a substantial proportion of barium rapidly decomposed water. The heat of the reaction is sufficient that the evolved hydrogen may ignite [Lab. Govt. Chemist 1965]. | | Reactivity Profile | Alloys containing a substantial amount of barium react violently with acids [Lab. Gov. Chemist 1965]. | | Hazard | Barium metal, in powder form, is flammable at room temperature. It must be stored in anoxygen-free atmosphere or in petroleum.
Many of barium’s compounds are toxic, especially barium chloride, which affects the functioningof the heart, causing ventricular fibrillation, an erratic heartbeat that can lead to death.Several of barium’s compounds are explosive as well as toxic if ingested or inhaled. Care shouldbe used when working with barium and other alkali metals in the laboratory or in industry. | | Health Hazard | The health effects of barium compounds depend on how well the compound dissolves
in water or in the stomach contents. Barium compounds that do not dissolve well, such
as barium sulfate, are considered not harmful. Barium carbonate dust and barium oxide
dust have been reported to be a bronchial irritant. While barium carbonate is a dermal
irritant, barium oxide is a nasal irritant. Occupational workers exposed to barium dust,
usually in the form of barium sulfate or carbonate, often develop a benign pneumoco-
niosis also called “baritosis.” The effect of baritosis has been shown to be reversible and
has not caused any kind of severe pulmonary adverse effect. Barium compounds that
do not dissolve in water are considered safe. However, the health effects of the different
barium compounds depend on the degree of their water solubility. The compounds that
dissolve well in water are known to cause harmful health effects when ingested in high
levels. Symptoms of poisoning include stomach irritation, brain swelling, muscle weak-
ness, liver and kidney damage, adverse effects to the heart, increased blood pressure,
changes in heart rhythm, effects on the spleen, difi culties in breathing, and swelling of
the brain. Exposures to high concentrations of barium through food and drinking water cause gastrointestinal disturbances. Barium causes vomiting, abdominal cramps, diar-
rhea, difi culties in breathing, increased or decreased blood pressure, numbness around
the face, and muscle weakness, changes in heart rhythm or paralysis, and possibly death.
Animals exposed to barium over long periods showed kidney damage, decreased body
weight, and fatal injury. Ingestion of large amounts of barium chloride (2 and 4 g) causes
fatal injury, because barium ions paralyze the heart. Acute poisoning with barium causes
nausea and diarrhea, cardiac problems, and muscular spasms, as well as cardiac arrest.
Thus, barium, at concentrations normally found in our environment, does not pose any
signii cant risk for the general population. However, for specii c subpopulations and
under conditions of high barium exposure, the potential for adverse health effects should
be taken into account. | | Fire Hazard | Flammable/combustible material. May ignite on contact with moist air or moisture. May burn rapidly with flare-burning effect. Some react vigorously or explosively on contact with water. Some may decompose explosively when heated or involved in a fire. May re-ignite after fire is extinguished. Runoff may create fire or explosion hazard. Containers may explode when heated. | | Industrial uses | Barium (symbol Ba) is a metallic element thatoccurs in combination in the minerals witheriteand barite, which are widely distributed. Themetal is silvery white in color and can beobtained by electrolysis from the chloride, butit oxidizes so easily that it is difficult to obtainin the metallic state. Its melting point is 850°C,and its specific gravity 3.78. The most extensiveuse of barium is in the form of its compounds.The salts that are soluble, such as sulfide andchloride, are toxic. An insoluble, nontoxic bariumsulfate salt is used in radiography. Bariumcompounds are used as pigments, in chemicalmanufacturing, and in deoxidizing alloys of tin, copper, lead, and zinc. Barium is introducedinto lead-bearing metals by electrolysis toharden the lead.Barium is also a key ingredient in ceramicsuperconductors. | | Safety Profile | Water and stomach
acids solubilize barium salts and can cause
poisoning. Symptoms are vomiting, colic,
diarrhea, slow irregular pulse, transient
hypertension, and convulsive tremors and
muscular paralysis. Death may occur in a
few hours to a few days. Half-life of barium
in bone has been estimated at 50 days. Dust
is dangerous and explosive when exposed to
heat, flame, or chemical reaction. Violent or
explosive reaction with water, CCh,
fluorotrichloromethane, trichloroethylene,
and C2Cl4. Incompatible with acids, C2CLF3,
C2H2FCl3, C2HCl3 and water, 1,1,2-
trichlorotrifluoroethane, and
fluorotrichloroethane. The powder may
ignite or explode in air or other oxidizing
gases. See also BARIUM COMPOUNDS. | | Potential Exposure | Metallic barium is used for removal of
residual gas in vacuum tubes and in alloys with nickel, lead,
calcium, magnesium, sodium, and lithium. Barium compounds
are used in the manufacture of lithopone (a white
pigment in paints), chlorine, sodium hydroxide, valves, and
green flares; in synthetic rubber vulcanization; X-ray diagnostic
work, glassmaking, papermaking, beet-sugar purification;
animal and vegetable oil refining. They are used in the
brick and tile, pyrotechnics, and electronics industries. They
are found in lubricants, pesticides, glazes, textile dyes and
finishes; pharmaceuticals; in cements which will be exposed
to saltwater; and barium is used as a rodenticide, a flux for
magnesium alloys, a stabilizer and mold lubricant in the rubber
and plastics industries, an extender in paints; a loader for
paper, soap, rubber, and linoleum; and as a fire extinguisher
for uranium or plutonium fires. | | Environmental Fate | Ingestion of toxic doses of barium affects the muscles, especially
the heart. Barium has a digitalis-type effect on the heart.
Ventricular fibrillation and slowed pulse rate are noted. This
may be related to barium’s tendency to displace potassium; the
resulting potassium deficiency causes muscle weakness. | | Shipping | UN1400 Barium, Hazard Class: 4.3; Labels:
4.3—Dangerous when wet material. UN1854 Barium alloys,
pyrophoric, Hazard Class: 4.2; Labels: 4.2—Spontaneously
combustible material. UN1564 Barium compound, n.o.s.,
Hazard Class: 6.1; Labels: 6.1—Poisonous materials. | | Purification Methods | Barium is cleaned by washing with diethyl ether to remove adhering paraffin, then filed in an argon-filled glove box, washed first with ethanol containing 2% conc HCl, then with dry ethanol. It is dried in a vacuum and stored under argon [Addison et al. J Chem Soc 3868 1962]. It has also been purified by double distillation under 10mm of argon pressure. | | Toxicity evaluation | Barium is a highly reactive metal that occurs naturally only in
a combined state. The element is released to environmental
media by both natural processes and anthropogenic sources.
Barium is released primarily to the atmosphere as a result of
industrial emissions during the mining, refining, and production
of barium and barium chemicals, fossil fuel combustion,
and entrainment of soil and rock dust into the air. In addition,
coal ash, containing widely variable amounts of barium, is also
a source of airborne barium particulates. Most barium released
to the environment from industrial sources is in forms that do
not become widely dispersed. In the atmosphere, barium is
likely to be present in particulate form. Although chemical
reactions may cause changes in speciation of barium in air, the
main mechanisms for the removal of barium compounds from
the atmosphere are likely to be wet and dry depositions. | | Incompatibilities | Barium powder may spontaneously
ignite on contact with air. It is a strong reducing agent and
Barium 337
reacts violently with oxidizers and acids. Reacts with water,
forming combustible hydrogen gas and barium hydroxide.
Reacts violently with halogenated hydrocarbon solvents,
causing a fire and explosion hazard. | | Waste Disposal | Barium in solution (see spill
handling) may be precipitated with soda ash and the sludge
may be landfilled. |
| | Barium Preparation Products And Raw materials |
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