Barium

Not to be confused with Baryon or Bohrium.

Chemical element with atomic number 56 (Ba)

Barium, 56Ba

Barium
Pronunciation| /ˈbɛəriəm/ ⓘ ​(BAIR-ee-əm)
Appearance| silvery gray; with a pale yellow tint[1]
Standard atomic weight Ar°(Ba)

* 137.327±0.007[2]
* 137.33±0.01 (abridged)[3]

Barium in the periodic table
|  |

| Hydrogen |  | Helium

|
|

Lithium | Beryllium |  | Boron | Carbon | Nitrogen | Oxygen | Fluorine | Neon
Sodium | Magnesium |  | Aluminium | Silicon | Phosphorus | Sulfur | Chlorine | Argon
Potassium | Calcium |  | Scandium | Titanium | Vanadium | Chromium | Manganese | Iron | Cobalt | Nickel | Copper | Zinc | Gallium | Germanium | Arsenic | Selenium | Bromine | Krypton
Rubidium | Strontium |  |  | Yttrium | Zirconium | Niobium | Molybdenum | Technetium | Ruthenium | Rhodium | Palladium | Silver | Cadmium | Indium | Tin | Antimony | Tellurium | Iodine | Xenon
Caesium | Barium | Lanthanum | Cerium | Praseodymium | Neodymium | Promethium | Samarium | Europium | Gadolinium | Terbium | Dysprosium | Holmium | Erbium | Thulium | Ytterbium | Lutetium | Hafnium | Tantalum | Tungsten | Rhenium | Osmium | Iridium | Platinum | Gold | Mercury (element) | Thallium | Lead | Bismuth | Polonium | Astatine | Radon
Francium | Radium | Actinium | Thorium | Protactinium | Uranium | Neptunium | Plutonium | Americium | Curium | Berkelium | Californium | Einsteinium | Fermium | Mendelevium | Nobelium | Lawrencium | Rutherfordium | Dubnium | Seaborgium | Bohrium | Hassium | Meitnerium | Darmstadtium | Roentgenium | Copernicium | Nihonium | Flerovium | Moscovium | Livermorium | Tennessine | Oganesson

caesium ← barium → lanthanum
Atomic number (Z)| 56
Group| group 2 (alkaline earth metals)
Period| period 6
Block|  s-block
Electron configuration| [Xe] 6s2
Electrons per shell| 2, 8, 18, 18, 8, 2
Physical properties
Phase at STP| solid
Melting point| 1000 K ​(727 °C, ​1341 °F)
Boiling point| 2118 K ​(1845 °C, ​3353 °F)
Density (at 20° C)| 3.594 g/cm3 [4]
when liquid (at m.p.)| 3.338 g/cm3
Heat of fusion| 7.12 kJ/mol
Heat of vaporization| 142 kJ/mol
Molar heat capacity| 28.07 J/(mol·K)
Vapor pressure

| P (Pa) | 1  | 10  | 100  | 1 k  | 10 k  | 100 k

|
|
|
|
|
|

at T (K) | 911  | 1038  | 1185  | 1388  | 1686  | 2170

Atomic properties
Oxidation states| common: +2
+1[5]
Electronegativity| Pauling scale: 0.89
Ionization energies|

* 1st: 502.9 kJ/mol
* 2nd: 965.2 kJ/mol
* 3rd: 3600 kJ/mol

Atomic radius| empirical: 222 pm
Covalent radius| 215±11 pm
Van der Waals radius| 268 pm
Spectral lines of barium
Other properties
Natural occurrence| primordial
Crystal structure|  ​body-centered cubic (bcc) (cI2)
Lattice constant|

a = 502.5 pm (at 20 °C)[4]
Thermal expansion| 20.47×10−6/K (at 20 °C)[4]
Thermal conductivity| 18.4 W/(m⋅K)
Electrical resistivity| 332 nΩ⋅m (at 20 °C)
Magnetic ordering| paramagnetic[6]
Molar magnetic susceptibility| +20.6×10−6 cm3/mol[7]
Young's modulus| 13 GPa
Shear modulus| 4.9 GPa
Bulk modulus| 9.6 GPa
Speed of sound thin rod| 1620 m/s (at 20 °C)
Mohs hardness| 1.25
CAS Number| 7440-39-3
History
Naming| from Greek βαρὺς (barys), meaning 'heavy'
Discovery| Carl Wilhelm Scheele (1772)
First isolation| Humphry Davy (1808)
Isotopes of barium

* v
* e

| Main isotopes[8] | Decay

|

| abun­dance | half-life (t1/2) | mode | pro­duct
130Ba  | 0.11%  | (0.5–2.7)×1021 y  | εε | 130Xe
131Ba  | synth | 11.52 d | β+ | 131Cs
132Ba  | 0.1%  | stable
133Ba  | synth  | 10.51 y | ε | 133Cs
134Ba  | 2.42%  | stable
135Ba  | 6.59%  | stable
136Ba  | 7.85%  | stable
137Ba  | 11.2%  | stable
138Ba  | 71.7%  | stable
140Ba  | synth  | 12.7534 d | β− | 140La
Category: Barium

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Barium is a chemical element; it has symbol Ba and atomic number 56\. It is the fifth element in group 2 and is a soft, silvery alkaline earth metal. Because of its high chemical reactivity, barium is never found in nature as a free element.

The most common minerals of barium are barite (barium sulfate, BaSO4) and witherite (barium carbonate, BaCO3). The name barium originates from the alchemical derivative "baryta", from Greek βαρὺς (barys), meaning 'heavy'. Baric is the adjectival form of barium. Barium was identified as a new element in 1772, but not reduced to a metal until 1808 with the advent of electrolysis.

Barium has few industrial applications. Historically, it was used as a getter for vacuum tubes and in oxide form as the emissive coating on indirectly heated cathodes. It is a component of YBCO (high-temperature superconductors) and electroceramics, and is added to steel and cast iron to reduce the size of carbon grains within the microstructure. Barium compounds are added to fireworks to impart a green color. Barium sulfate is used as an insoluble additive to oil well drilling fluid. In a purer form it is used as X-ray radiocontrast agents for imaging the human gastrointestinal tract. Water-soluble barium compounds are poisonous and have been used as rodenticides.

## Characteristics

[edit]

### Physical properties

[edit]

Oxidized barium

Barium is a soft, silvery-white metal, with a slight golden shade when ultrapure.[9]: 2 The silvery-white color of barium metal rapidly vanishes upon oxidation in air yielding a dark gray layer containing the oxide. Barium has a medium specific weight and high electrical conductivity. Because barium is difficult to purify, many of its properties have not been accurately determined.[9]: 2

At room temperature and pressure, barium metal adopts a body-centered cubic structure, with a barium–barium distance of 503 picometers, expanding with heating at a rate of approximately 1.8×10−5/°C.[9]: 2 It is a soft metal with a Mohs hardness of 1.25.[9]: 2 Its melting temperature of 1,000 K (730 °C; 1,340 °F)[10]: 4–43 is intermediate between those of the lighter strontium (1,050 K or 780 °C or 1,430 °F)[10]: 4–86 and heavier radium (973 K or 700 °C or 1,292 °F);[10]: 4–78 however, its boiling point of 2,170 K (1,900 °C; 3,450 °F) exceeds that of strontium (1,655 K or 1,382 °C or 2,519 °F).[10]: 4–86 The density (3.62 g/cm3)[10]: 4–43 is again intermediate between those of strontium (2.36 g/cm3)[10]: 4–86 and radium (≈5 g/cm3).[10]: 4–78

### Chemical reactivity

[edit]

Barium is chemically similar to magnesium, calcium, and strontium, but more reactive. Its compounds are almost invariably found in the +2 oxidation state. As expected for a highly electropositive metal, barium's reaction with chalcogens is highly exothermic (release energy). Barium reacts with atmospheric oxygen in air at room temperature. For this reason, metallic barium is often stored under oil or in an inert atmosphere.[9]: 2 Reactions with other nonmetals, such as carbon, nitrogen, phosphorus, silicon, and hydrogen, proceed upon heating.[9]: 2–3 Reactions with water and alcohols are also exothermic and release hydrogen gas:[9]: 3

Ba + 2 ROH → Ba(OR)2 \+ H2↑ (R is an alkyl group or a hydrogen atom)

Barium reacts with ammonia to form the electride [Ba(NH3)6](e−)2, which near room temperature gives the amide Ba(NH2)2.[11]

The metal is readily attacked by acids. Sulfuric acid is a notable exception because passivation stops the reaction by forming the insoluble barium sulfate on the surface.[12] Barium combines with several other metals, including aluminium, zinc, lead, and tin, forming intermetallic phases and alloys.[13]

### Compounds

[edit]

Selected alkaline earth and zinc salts densities, g/cm3 | O2−
| S2−
| F−
| Cl−
| SO2−
4 | CO2−
3 | O2−
2 | H−

|
|
|
|
|
|
|
|

Ca2+
[10]: 4–48–50 | 3.34  | 2.59  | 3.18  | 2.15  | 2.96  | 2.83  | 2.9  | 1.7
Sr2+
[10]: 4–86–88 | 5.1  | 3.7  | 4.24  | 3.05  | 3.96  | 3.5  | 4.78  | 3.26
Ba2+
[10]: 4–43–45 | 5.72 | 4.3 | 4.89 | 3.89 | 4.49 | 4.29 | 4.96 | 4.16
Zn2+
[10]: 4–95–96 | 5.6  | 4.09  | 4.95  | 2.09  | 3.54  | 4.4  | 1.57  | —

Barium salts are typically white when solid and colorless when dissolved.[14] They are denser than the strontium or calcium analogs, except for the halides (see table; zinc is given for comparison).

Barium hydroxide ("baryta") was known to alchemists, who produced it by heating barium carbonate. Unlike calcium hydroxide, it absorbs very little CO2 in aqueous solutions and is therefore insensitive to atmospheric fluctuations. This property is used in calibrating pH equipment.

Barium compounds burn with a green to pale green flame, which is an efficient test to detect a barium compound. The color results from spectral lines at 455.4, 493.4, 553.6, and 611.1 nm.[9]: 3

Organobarium compounds are a growing field of knowledge: recently discovered are dialkylbariums and alkylhalobariums.[9]: 3

### Isotopes

[edit]

Main article: Isotopes of barium

Barium found in the Earth's crust is a mixture of seven primordial nuclides, barium-130, 132, and 134 through 138.[15] Barium-130 undergoes very slow radioactive decay to xenon-130 by double beta plus decay, with a half-life of (0.5–2.7)×1021 years (about 1011 times the age of the universe). Its abundance is ≈0.1% that of natural barium.[15] Theoretically, barium-132 can similarly undergo double beta decay to xenon-132; this decay has not been detected.[16] The radioactivity of these isotopes is so weak that they pose no danger to life.

Of the stable isotopes, barium-138 composes 71.7% of all barium; other isotopes have decreasing abundance with decreasing mass number.[15]

In total, barium has 40 known isotopes, ranging in mass between 114 and 153. The most stable artificial radioisotope is barium-133 with a half-life of approximately 10.51 years. Five other isotopes have half-lives longer than a day.[16] Barium also has 10 meta states, of which barium-133m1 is the most stable with a half-life of about 39 hours.[16]

## History

[edit]

Portrait of Sir Humphry Davy by Thomas Lawrence, 1821. Sir Humphry Davy was the first to isolate barium metal.

Alchemists in the early Middle Ages knew about some barium minerals. Smooth pebble-like stones of mineral baryte were found in volcanic rock near Bologna, Italy, and so were called "Bologna stones". Alchemists were attracted to them because after exposure to light they would glow for years.[17] The phosphorescent properties of baryte heated with organics were described by V. Casciorolus in 1602.[9]: 5

Carl Scheele determined that baryte contained a new element in 1772, but could not isolate barium, only barium oxide. Johan Gottlieb Gahn also isolated barium oxide two years later in similar studies. Oxidized barium was at first called "barote" by Guyton de Morveau, a name that was changed by Antoine Lavoisier to baryte (in French) or baryta (in Latin). Also in the 18th century, English mineralogist William Withering noted a heavy mineral in the lead mines of Cumberland, now known to be witherite. Barium was first isolated by electrolysis of molten barium salts in 1808 by Sir Humphry Davy in England.[18] Davy, by analogy with calcium, named "barium" after baryta, with the "-ium" ending signifying a metallic element.[17] Robert Bunsen and Augustus Matthiessen obtained pure barium by electrolysis of a molten mixture of barium chloride and ammonium chloride.[19][20]

The production of pure oxygen in the Brin process was a large-scale application of barium peroxide in the 1880s, before it was replaced by electrolysis and fractional distillation of liquefied air in the early 1900s. In this process barium oxide reacts at 500–600 °C (932–1,112 °F) with air to form barium peroxide, which decomposes above 700 °C (1,292 °F) by releasing oxygen:[21][22]

2 BaO + O2 ⇌ 2 BaO2

Barium sulfate was first applied as a radiocontrast agent in X-ray imaging of the digestive system in 1908.[23]

## Occurrence and production

[edit]

The abundance of barium is 0.0425% in the Earth's crust and 13 μg/L in sea water. The primary commercial source of barium is baryte (also called barytes or heavy spar), a barium sulfate mineral.[9]: 5 with deposits in many parts of the world. Another commercial source, far less important than baryte, is witherite, barium carbonate. The main deposits are located in Britain, Romania, and the former USSR.[9]: 5

Barite, left to right: appearance, graph showing trends in production over time, and the map showing shares of the most important producer countries in 2010.

The baryte reserves are estimated between 0.7 and 2 billion tonnes. The highest production, 8.3 million tonnes, was achieved in 1981, but only 7–8% was used for barium metal or compounds.[9]: 5 Baryte production has risen since the second half of the 1990s from 5.6 million tonnes in 1996 to 7.6 in 2005 and 7.8 in 2011. China accounts for more than 50% of this output, followed by India (14% in 2011), Morocco (8.3%), US (8.2%), Iran and Kazakhstan (2.6% each) and Turkey (2.5%).[24]

The mined ore is washed, crushed, classified, and separated from quartz. If the quartz penetrates too deeply into the ore, or the iron, zinc, or lead content is abnormally high, then froth flotation is used. The product is a 98% pure baryte (by mass); the purity should be no less than 95%, with a minimal content of iron and silicon dioxide.[9]: 7 It is then reduced by carbon to barium sulfide:[9]: 6

BaSO4 \+ 2 C → BaS + 2 CO2

The water-soluble barium sulfide is the starting point for other compounds: treating BaS with oxygen produces the sulfate, with nitric acid the nitrate, with aqueous carbon dioxide the carbonate, and so on.[9]: 6 The nitrate can be thermally decomposed to yield the oxide.[9]: 6 Barium metal is produced by reduction with aluminium at 1,100 °C (2,010 °F). The intermetallic compound BaAl4 is produced first:[9]: 3

3 BaO + 14 Al → 3 BaAl4 \+ Al2O3

BaAl4 is an intermediate reacted with barium oxide to produce the metal. Note that not all barium is reduced.[9]: 3

8 BaO + BaAl4 → Ba↓ + 7 BaAl2O4

The remaining barium oxide reacts with the formed aluminium oxide:[9]: 3

BaO + Al2O3 → BaAl2O4

and the overall reaction is[9]: 3

4 BaO + 2 Al → 3 Ba↓ + BaAl2O4

Barium vapor is condensed and packed into molds in an atmosphere of argon.[9]: 3 This method is used commercially, yielding ultrapure barium.[9]: 3 Commonly sold barium is about 99% pure, with main impurities being strontium and calcium (up to 0.8% and 0.25%) and other contaminants contributing less than 0.1%.[9]: 4

A similar reaction with silicon at 1,200 °C (2,190 °F) yields barium and barium metasilicate.[9]: 3 Electrolysis is not used because barium readily dissolves in molten halides and the product is rather impure.[9]: 3

Benitoite crystals on natrolite. The mineral is named for the San Benito River in San Benito County where it was first found.

### Gemstone

[edit]

The barium mineral, benitoite (barium titanium silicate), occurs as a very rare blue fluorescent gemstone, and is the official state gem of California.

### Barium in seawater

[edit]

Barium exists in seawater as the Ba2+ ion with an average oceanic concentration of 109 nmol/kg.[25] Barium also exists in the ocean as BaSO4, or barite.[26] Barium has a nutrient-like profile[27] with a residence time of 10,000 years.[25]

Barium shows a relatively consistent concentration in upper ocean seawater, excepting regions of high river inputs and regions with strong upwelling.[28] There is little depletion of barium concentrations in the upper ocean for an ion with a nutrient-like profile, thus lateral mixing is important.[28] Barium isotopic values show basin-scale balances instead of local or short-term processes.[28]

## Applications

[edit]

### Metal and alloys

[edit]

Barium, as a metal or when alloyed with aluminium, is used to remove unwanted gases (gettering) from vacuum tubes, such as TV picture tubes.[9]: 4 Barium is suitable for this purpose because of its low vapor pressure and reactivity towards oxygen, nitrogen, carbon dioxide, and water; it can even partly remove noble gases by dissolving them in the crystal lattice. This application is gradually disappearing due to the rising popularity of the tubeless LCD, LED, and plasma sets.[9]: 4

Other uses of elemental barium are minor and include an additive to silumin (aluminium–silicon alloys) that refines their structure, as well as[9]: 4

* bearing alloys;
* lead–tin soldering alloys – to increase the creep resistance;
* alloy with nickel for spark plugs;
* additive to steel and cast iron as an inoculant;
* alloys with calcium, manganese, silicon, and aluminium as high-grade steel deoxidizers.

### Barium sulfate and baryte

[edit]

Amoebiasis as seen in a radiograph of a barium-filled colon

Barium sulfate (the mineral baryte, BaSO4) is important to the petroleum industry as a drilling fluid in oil and gas wells.[10]: 4–5 The precipitate of the compound (called "blanc fixe", from the French for "permanent white") is used in paints and varnishes; as a filler in ringing ink, plastics, and rubbers; as a paper coating pigment; and in nanoparticles, to improve physical properties of some polymers, such as epoxies.[9]: 9

Barium sulfate has a low toxicity and relatively high density of ca. 4.5 g/cm3 (and thus opacity to X-rays). For this reason it is used as a radiocontrast agent in X-ray imaging of the digestive system ("barium meals" and "barium enemas").[10]: 4–5 Lithopone, a pigment that contains barium sulfate and zinc sulfide, is a permanent white with good covering power that does not darken when exposed to sulfides.[29]

### Other barium compounds

[edit]

Green barium fireworks

Other compounds of barium find only niche applications, limited by the toxicity of Ba2+ ions (see § Toxicity), which is not a problem for the insoluble BaSO4.

* Barium oxide coating on the electrodes of fluorescent lamps facilitates the release of electrons.
* By its great atomic density, barium carbonate increases the refractive index and luster of glass[10]: 4–5 and reduces leaks of X-rays from CRT screens.[9]: 12–13
* Barium, typically as barium nitrate imparts a yellow or "apple" green color to fireworks when no chlorine donors are present.[30]; emerald greens are generated using chlorine donors (barium chlorate acting as the donor and oxidizer in many formulas) to produce barium chloride in-situ.[citation needed]
* Barium peroxide is a catalyst in the aluminothermic reaction (thermite) for welding rail tracks. It is also a green flare in tracer ammunition and a bleaching agent.[31]
* Barium titanate is a promising electroceramic.[32]
* Barium fluoride is used for optics in infrared applications because of its wide transparency range of 0.15–12 micrometers.[33]
* YBCO was the first high-temperature superconductor cooled by liquid nitrogen, with a transition temperature of 93 K (−180.2 °C; −292.3 °F) greater than the boiling point of nitrogen (77 K or −196.2 °C or −321.1 °F).[34]
* Ferrite, a type of sintered ceramic composed of iron oxide (Fe2O3) and barium oxide (BaO), is both electrically nonconductive and ferrimagnetic, and can be temporarily or permanently magnetized.

### Palaeoceanography

[edit]

The lateral mixing of barium is caused by water mass mixing and ocean circulation.[35] Global ocean circulation reveals a strong correlation between dissolved barium and silicic acid.[35] The large-scale ocean circulation combined with remineralization of barium show a similar correlation between dissolved barium and ocean alkalinity.[35]

Dissolved barium's correlation with silicic acid can be seen both vertically and spatially.[36] Particulate barium shows a strong correlation with particulate organic carbon or POC.[36] Barium is becoming more popular as a base for palaeoceanographic proxies.[36] With both dissolved and particulate barium's links with silicic acid and POC, it can be used to determine historical variations in the biological pump, carbon cycle, and global climate.[36]

The barium particulate barite (BaSO4), as one of many proxies, can be used to provide a host of historical information on processes in different oceanic settings (water column, sediments, and hydrothermal sites).[26] In each setting there are differences in isotopic and elemental composition of the barite particulate.[26] Barite in the water column, known as marine or pelagic barite, reveals information on seawater chemistry variation over time.[26] Barite in sediments, known as diagenetic or cold seeps barite, gives information about sedimentary redox processes.[26] Barite formed via hydrothermal activity at hydrothermal vents, known as hydrothermal barite, reveals alterations in the condition of the earth's crust around those vents.[26]

## Toxicity

[edit]

Barium  Hazards

GHS labelling:[37]

Pictograms

Signal word

| Danger

Hazard statements

| H228, H260, H301, H314

Precautionary statements

| P210, P231+P232, P260, P280, P303+P361+P353, P304+P340+P310, P305+P351+P338
NFPA 704 (fire diamond)  |

Chemical compound

Soluble barium compounds have LD50 near 10 mg/kg (oral rats). Symptoms include "convulsions... paralysis of the peripheral nerve system ... severe inflammation of the gastrointestinal tract".[9]: 18 The insoluble sulfate is nontoxic and is not classified as a dangerous goods in transport regulations.[9]: 9

Little is known about the long term effects of barium exposure.[38] The US EPA considers it unlikely that barium is carcinogenic when consumed orally. Inhaled dust containing insoluble barium compounds can accumulate in the lungs, causing a benign condition called baritosis.[39]

Barium carbonate has been used as a rodenticide.[40] Though considered obsolete, it may still be in use in some countries.[41]

## See also

[edit]

* Han purple and Han blue – synthetic barium copper silicate pigments developed and used in ancient and imperial China

## References

[edit]

1. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 112\. ISBN 978-0-08-037941-8.
2. ^ "Standard Atomic Weights: Barium". CIAAW. 1985.
3. ^ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
4. ^ a b c Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. ISBN 978-1-62708-155-9.
5. ^ Xu, Wei; Lerner, Michael M. (2018). "A New and Facile Route Using Electride Solutions to Intercalate Alkaline Earth Ions into Graphite". Chemistry of Materials. 30 (19): 6930–6935\. doi:10.1021/acs.chemmater.8b03421. S2CID 105295721.
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18. ^ Davy, H (1808). "Electro-chemical researches on the decomposition of the earths; with observations on the metals obtained from the alkaline earths, and on the amalgam procured from ammonia". Philosophical Transactions of the Royal Society of London. 98: 333–370\. Bibcode:1808RSPT...98..333D. doi:10.1098/rstl.1808.0023. S2CID 96364168.
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26. ^ a b c d e f Griffith, Elizabeth M.; Paytan, Adina (2012). "Barite in the ocean – occurrence, geochemistry and palaeoceanographic applications". Sedimentology. 59 (6): 1817–1835\. Bibcode:2012Sedim..59.1817G. doi:10.1111/j.1365-3091.2012.01327.x. ISSN 1365-3091. S2CID 28056031.
27. ^ "Graph". www.mbari.org. Retrieved 2020-11-24.
28. ^ a b c Hsieh, Yu-Te; Henderson, Gideon M. (2017). "Barium stable isotopes in the global ocean: Tracer of Ba inputs and utilization". Earth and Planetary Science Letters. 473: 269–278\. Bibcode:2017E&PSL.473..269H. doi:10.1016/j.epsl.2017.06.024.
29. ^ Jones, Chris J. & Thornback, John (2007). Medicinal applications of coordination chemistry. Royal Society of Chemistry. p. 102. ISBN 978-0-85404-596-9.
30. ^ Russell, Michael S. & Svrcula, Kurt (2008). Chemistry of Fireworks. Royal Society of Chemistry. p. 110\. ISBN 978-0-85404-127-5.
31. ^ Brent, G. F.; Harding, M. D. (1995). "Surfactant coatings for the stabilization of barium peroxide and lead dioxide in pyrotechnic compositions". Propellants, Explosives, Pyrotechnics. 20 (6): 300. doi:10.1002/prep.19950200604.
32. ^ Wadhawan, Vinod K. (2000). Introduction to ferroic materials. CRC Press. p. 740\. ISBN 978-90-5699-286-6.
33. ^ "Crystran Ltd. Optical Component Materials". crystran.co.uk. Archived from the original on 2010-06-11. Retrieved 2010-12-29.
34. ^ Wu, M.; Ashburn, J.; Torng, C.; Hor, P.; Meng, R.; Gao, L.; Huang, Z.; Wang, Y.; Chu, C. (1987). "Superconductivity at 93 K in a New Mixed-Phase Y-Ba-Cu-O Compound System at Ambient Pressure". Physical Review Letters. 58 (9): 908–910\. Bibcode:1987PhRvL..58..908W. doi:10.1103/PhysRevLett.58.908. PMID 10035069.
35. ^ a b c Pyle, Kimberley M.; Hendry, Katharine R.; Sherrell, Robert M.; Legge, Oliver; Hind, Andrew J.; Bakker, Dorothee; Venables, Hugh; Meredith, Michael P. (2018-08-20). "Oceanic fronts control the distribution of dissolved barium in the Southern Ocean" (PDF). Marine Chemistry. 204: 95–106\. Bibcode:2018MarCh.204...95P. doi:10.1016/j.marchem.2018.07.002. hdl:1983/ff280483-67cd-46a3-9548-1a782098ea27. ISSN 0304-4203. S2CID 104170533.
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41. ^ "Barium carbonate". Pesticide Properties Database.

## External links

[edit]

* Barium at The Periodic Table of Videos (University of Nottingham)
* Elementymology & Elements Multidict
* 3-D Holographic Display Using Strontium Barium Niobate

* v
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Barium compounds

* BaB6
* Ba(BO2)2
* BaBr2
* Ba(BrO3)2
* Ba(CH3CO2)2
* Ba(C5H7O2)2
* Ba(ClO)2
* BaC2
* BaCO3
* BaC2O4
* Ba(ClO3)2
* BaClF
* Ba(ClO4)2
* Ba(CN)2
* BaCl2
* BaCrO4
* BaF2
* BaFeO4
* BaFe2O4
* BaH2
* BaI2
* Ba(IO3)2
* BaMnO4
* Ba(MnO4)2
* Ba(N3)2
* Ba(NO2)2
* Ba(NO3)2
* BaO
* BaO2
* Ba(OH)2
* Ba(PO3)2
* Ba3(PO4)2
* BaS
* BaSe
* BaSeO4
* Ba(SCN)2
* BaSO3
* BaSO4
* BaRuO3
* BaSnO3
* BaTiO3
* Ba2TiO4
* BaWO4
* BaZnGa
* Sr2Ba1−xNb2O6
* YBa2Cu3O7−x
* BaGeF6
* BaSiF6

* v
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* e

Periodic table

|  | 1 | 2 |  | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18

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1 | H |  | He
2 | Li | Be |  | B | C | N | O | F | Ne
3 | Na | Mg |  | Al | Si | P | S | Cl | Ar
4 | K | Ca |  | Sc | Ti | V | Cr | Mn | Fe | Co | Ni | Cu | Zn | Ga | Ge | As | Se | Br | Kr
5 | Rb | Sr |  | Y | Zr | Nb | Mo | Tc | Ru | Rh | Pd | Ag | Cd | In | Sn | Sb | Te | I | Xe
6 | Cs | Ba | La | Ce | Pr | Nd | Pm | Sm | Eu | Gd | Tb | Dy | Ho | Er | Tm | Yb | Lu | Hf | Ta | W | Re | Os | Ir | Pt | Au | Hg | Tl | Pb | Bi | Po | At | Rn
7 | Fr | Ra | Ac | Th | Pa | U | Np | Pu | Am | Cm | Bk | Cf | Es | Fm | Md | No | Lr | Rf | Db | Sg | Bh | Hs | Mt | Ds | Rg | Cn | Nh | Fl | Mc | Lv | Ts | Og

| s-block | f-block | d-block | p-block

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Alkaline earth metals

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Beryllium

Atomic Number: 4
Atomic Weight: 9.012182
Melting Point: 1560.15 K
Boiling Point: 2742 K
Specific mass: 1.85 g/cm3
Electronegativity: 1.57

Magnesium

Atomic Number: 12
Atomic Weight: 24.3050
Melting Point: 923.15 K
Boiling Point: 1363 K
Specific mass: 1.738 g/cm3
Electronegativity: 1.31

Calcium

Atomic Number: 20
Atomic Weight: 40.078
Melting Point: 1112.15 K
Boiling Point: 1757 K
Specific mass: 1.54 g/cm3
Electronegativity: 1

Strontium

Atomic Number: 38
Atomic Weight: 87.62
Melting Point: 1042.15 K
Boiling Point: 1655 K
Specific mass: 2.64 g/cm3
Electronegativity: 0.95

Barium

Atomic Number: 56
Atomic Weight: 137.327
Melting Point: 1002.15 K
Boiling Point: 2170 K
Specific mass: 3.594 g/cm3
Electronegativity: 0.89

Radium

Atomic Number: 88
Atomic Weight: [226]
Melting Point: 973.15 K
Boiling Point: 2010 K
Specific mass: 5.5 g/cm3
Electronegativity: 0.9

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Portals:

* Chemistry
* Medicine

Barium at Wikipedia's sister projects:

* Definitions from Wiktionary
* Media from Commons
* Texts from Wikisource
* Resources from Wikiversity

Authority control databases: National |

* Germany
* United States
* France
* BnF data
* Japan
* Czech Republic
* Spain
* Latvia
* Israel

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*[P]: Pressure
*[T]: Temperature
*[v]: View this template
*[e]: Edit this template
*[H228]: H228: Flammable solid
*[H260]: H260: In contact with water releases flammable gases which may ignite spontaneously
*[H301]: H301: Toxic if swallowed
*[H314]: H314: Causes severe skin burns and eye damage
*[P210]: P210: Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
*[P231+P232]: P231+P232: Handle and store contents under inert gas. Protect from moisture
*[P260]: P260: Do not breathe dust/fume/gas/mist/vapours/spray.
*[P280]: P280: Wear protective gloves/protective clothing/eye protection/face protection.
*[P303+P361+P353]: P303+P361+P353: IF ON SKIN (or hair): Remove/Take off immediately all contaminated clothing. Rinse skin with water [or shower].
*[P304+P340+P310]: P304+P340+P310: IF INHALED: Remove victim to fresh air and keep at rest in a position comfortable for breathing. Immediately call a POISON CENTER or doctor/physician.
*[P305+P351+P338]: P305+P351+P338: IF IN EYES: Rinse continuously with water for several minutes. Remove contact lenses if present and easy to do. Continue rinsing.
*[t]: Discuss this template