Barium (Ba)
alkaline-earth-metalSolid
Standard Atomic Weight
137.327 uElectron configuration
[Xe] 6s2Melting point
726.85 °CBoiling point
1896.85 °CDensity
3620 kg/m³Oxidation states
+1, +2Electronegativity (Pauling)
0.89Ionization energy (1st)
5.211665 eVDiscovery year
1808Atomic radius
215 pmDetails
Barium is a soft alkaline earth metal, below strontium and above radium in group 2. It is highly reactive, forms Ba²⁺ compounds almost exclusively, and is not found free in nature. Its most important minerals are barite, barium sulfate, and witherite, barium carbonate. The element is technologically significant less as a metal than through dense, insoluble, or optically useful compounds.
Barium is a metallic element, soft, and when pure is silvery white; it belongs to the alkaline earth group, chemically resembling calcium. 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.
Barium was first isolated by Sir Humphry Davy, an English chemist, in 1808 through the electrolysis of molten baryta (BaO). Barium is never found free in nature since it reacts with oxygen in the air, forming barium oxide (BaO), and with water, forming barium hydroxide (Ba(OH)2) and hydrogen gas (H2). Barium is most commonly found as the mineral barite (BaSO4) and witherite (BaCO3) and is primarily produced through the electrolysis of barium chloride (BaCl2).
From the Greek word barys, heavy. Baryta was distinguished from lime by Scheele in 1774; the element was discovered by Sir Humphrey Davy in 1808.
Pure barium is a silvery-white to pale yellow metal when freshly cut. It tarnishes rapidly in air as oxide, nitride, and peroxide-containing surface films form. The metal is soft, relatively dense for an alkaline earth metal, and is normally stored under oil or inert gas.
Elemental barium has limited direct use because of its reactivity. It has been used as a getter in vacuum tubes, where it removes residual gases by forming stable compounds. Barium compounds have broader roles: barium sulfate (BaSO₄) is used as a radiopaque contrast material and as an inert filler; barium titanate (BaTiO₃) is a ferroelectric ceramic used in capacitors and related devices; and barium nitrate (Ba(NO₃)₂) and barium chlorate (Ba(ClO₃)₂) can produce green colors in pyrotechnics.
Barium is used as a getter, a material that combines with and removes trace gases from vacuum tubes.
Barium sulfate (BaSO4), a common barium compound, is used as a filler for rubber, plastics and resins. It can be combined with zinc oxide (ZnO) to make a white pigment known as lithophone or with sodium sulfate (Na2SO4) to make another white pigment known as blanc fixe. Stones made from impure barium sulfate glow when exposed to light and will glow in the dark for up to six years if intensely heated in the presence of charcoal. These stones, known as Bologna stones, were discovered near Bologna, Italy in the early 1500s and were thought to possess magical properties by alchemists. Although all barium compounds are poisonous, barium sulfate can be safely ingested since it does not dissolve in water. It is also a good absorber of X-rays and, when swallowed, can be used to produce X-ray images of the intestinal tract.
Barium carbonate (BaCO3), another common barium compound, is used in the manufacture of ceramics and some types of glass. It is a component in clay slurries used in drilling oil wells. Barium carbonate is used to purify some chemical solutions and is the primary base material for the manufacture of other barium compounds.
Barium forms several other useful compounds. Barium nitrate (Ba(NO3)2) burns with a bright green color and is used in signal flares and fireworks. Barium chloride (BaCl) is used as a water softener. Barium oxide (BaO) easily absorbs moisture and is used as a desiccant. Barium peroxide (BaO2) forms hydrogen peroxide (H2O2) when it is mixed with water and is used as a bleaching agent that activates when wet. Barium titanate (BaTiO3) is used as a dielectric material in capacitors. Barium ferrite (BaO·6Fe2O3) is used to make magnets.
Barium-137m, a radioactive form of barium produced by the decay of cesium-137, has a relatively short half-life and is commonly used in high school and college physics half-life determination experiments.
The metal is used as a "getter" in vacuum tubes. The most important compounds are the peroxide, 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 is also used in paint, in X-ray diagnostic work, and in glassmaking. Barite is extensively used as a weighing agent in oil well drilling fluids, and is used in making rubber. The carbonate has been used as a rat poison, while the nitrate and chlorate give colors in pyrotechnics. The impure sulfide phosphoresces after exposure to the light. All barium compounds that are water or acid soluble are poisonous. Naturally occurring barium is a mixture of seven stable isotopes. Twenty two other radioactive isotopes are known to exist.
Isotopes in Earth/Planetary Science
Because molecules, atoms, and ions of the stable isotopes of barium possess slightly different physical and chemical properties, they can be fractionated during physical, chemical, and biological processes, giving rise to variations in isotopic abundances and in atomic weights. von Allmen et al. [410] K. v. Allmen, M. E. Böttcher, E. Samankassou, T. F. Nägler. Chem. Geol.277, 70 (2010). observed barium isotopic fractionation in the global barium cycle (Fig. IUPAC.56.1).
High-precision barium isotope measurements reveal differences of up to 25 parts per million in the isotope-amount ratio n(137Ba)/n(136Ba) and 60 parts per million in the n(138Ba)/n(136Ba) ratio between chondrites and the Earth. These differences probably arose from incomplete mixing of nucleosynthetic material in the solar nebula. Barium isotopes may be the decay products of now-extinct 135Cs (with a half-life of about 1.6×106 years), which is thought to be a nucleosynthetic component. Chondritic meteorites have a slight excess of supernova-derived material as compared to Earth, demonstrating that the solar nebula was not perfectly homogenized upon formation (Fig. IUPAC.56.1) [411] M. C. Ranen, S. B. Jacobsen. Science314, 809 (2006)., [412] H. Hidaka, Y. Ohta, S. Yoneda. Earth. Planet. Sci. Lett.214, 455 (2003)., [413] S. B. Jacobsen, M. C. Ranen. Geochim. Cosmochim. Acta70, A286 (2006)..
Barium chemistry is dominated by the +2 oxidation state and by large, mostly ionic Ba²⁺ salts. Barium oxide (BaO) is a basic oxide, while barium hydroxide (Ba(OH)₂) is a strong base. Barium sulfate (BaSO₄) is exceptionally insoluble, a property central to analytical sulfate tests and medical contrast use. Barium carbonate (BaCO₃), barium chloride (BaCl₂), and barium nitrate (Ba(NO₃)₂) are important laboratory or industrial salts, but soluble barium salts are toxic. Mixed oxides such as barium titanate (BaTiO₃) are important functional ceramics.
See more information at the Barium compound page.
Metallic barium reacts with moisture and can ignite or release hydrogen, so it is handled as an air-sensitive reactive metal. Soluble barium compounds, including barium chloride (BaCl₂) and barium nitrate (Ba(NO₃)₂), are poisonous because Ba²⁺ interferes with potassium ion transport and muscle function. Barium sulfate (BaSO₄) is far less hazardous by ingestion because of its very low solubility, provided it is free of soluble barium impurities.
Barium occurs naturally in crustal rocks, especially as barite, barium sulfate (BaSO₄), and witherite, barium carbonate (BaCO₃). Its mobility depends strongly on sulfate, carbonate, and pH conditions; insoluble sulfate tends to immobilize it, while soluble salts can enter groundwater locally. Barium is not an essential nutrient for most organisms, and elevated soluble barium can be harmful to aquatic and terrestrial life.
Barium is supplied mainly through mining and processing of barite, barium sulfate (BaSO₄), with smaller contributions from other barium minerals where available. Much barite is consumed directly after grinding, especially where high density and chemical inertness are useful, rather than being converted to metal. Barium metal is made by reducing barium compounds under controlled conditions and is a small specialty product. Demand is driven by drilling fluids, fillers, ceramics, glass, pyrotechnics, and chemical manufacture; substitution is possible in some uses but difficult where density, insolubility, or specific electronic properties are required.
It is found only in combination with other elements, chiefly with sulfate and carbonate and is prepared by electrolysis of the chloride.
Barium is heavier than iron and is formed mainly by neutron-capture processes in stars, especially the slow s-process in evolved stars and the rapid r-process in explosive or merger environments. Its spectral lines are important in stellar abundance studies, and barium enrichment in some stars records past nucleosynthesis and mass transfer. In planetary materials it is a trace lithophile element concentrated in minerals and melts rather than metallic cores.
- Barium sulfate is so insoluble that it can be swallowed for X-ray imaging despite barium ion toxicity.
- The name comes from Greek barys, meaning heavy, reflecting the high density of barite.
- Barium flame tests give an apple-green color, though impurities can mask it.
- Natural barium is a mixture of several stable isotopes, with ¹³⁸Ba the most abundant.
- Barium titanate was one of the first widely important ferroelectric ceramics.
Images
Properties
Physical
- Atomic radius (empirical)
- 215 pm Compare Atomic radius (empirical) of all elements →
- Covalent radius
- 215 pm Compare Covalent radius of all elements →
- Van der Waals radius
- 268 pm Compare Van der Waals radius of all elements →
- Metallic radius
- 198 pm Compare Metallic radius of all elements →
- Density
- 3620 kg/m³ Compare Density of all elements →
- Molar volume
- 0.039 L/mol
- Phase at STP
- Solid Compare Phase at STP of all elements →
- Melting point
- 726.85 °C Compare Melting point of all elements →
- Boiling point
- 1896.85 °C Compare Boiling point of all elements →
- Specific heat capacity
- 0.204 J/(g·K) Compare Specific heat capacity of all elements →
- Molar heat capacity
- 28.07 J/(mol·K) Compare Molar heat capacity of all elements →
- Crystal structure
- Body-centered cubic Compare Crystal structure of all elements →
Chemical
- Electronegativity (Pauling)
- 0.89 Compare Electronegativity (Pauling) of all elements →
- Electronegativity (Allen)
- 0.881
- Electron affinity
- 0.1447 eV
- Ionization energy (1st)
- 5.211665 eV Compare Ionization energy (1st) of all elements →
- Ionization energy (2nd)
- 10.00386 eV Compare Ionization energy (2nd) of all elements →
- Ionization energy (3rd)
- 35.843923 eV Compare Ionization energy (3rd) of all elements →
- Ionization energy (4th)
- 47.000162 eV Compare Ionization energy (4th) of all elements →
- Ionization energy (5th)
- 58.0002 eV Compare Ionization energy (5th) of all elements →
- Oxidation states
- +1, +2 Compare Oxidation states of all elements →
- Valence electrons
- 2 Compare Valence electrons of all elements →
- Electron configuration
- [Xe] 6s2
Thermodynamic
- Heat of fusion
- 0.07939058 eV Compare Heat of fusion of all elements →
- Heat of vaporization
- 1.461367 eV Compare Heat of vaporization of all elements →
- Heat of sublimation
- 1.865575 eV
- Heat of atomization
- 1.865575 eV
- Atomization enthalpy
- 1.856247 eV
Nuclear
- Protons
- 56 Compare Protons of all elements →
- Neutrons
- 82 Compare Neutrons of all elements →
- Known isotopes
- 42 Compare Known isotopes of all elements →
- Stable isotopes
- 5 Compare Stable isotopes of all elements →
- Most stable isotope
- Ba-138
- Discovery year
- 1808
Abundance
- Abundance (Earth's crust)
- 425 mg/kg Compare Abundance (Earth's crust) of all elements →
- Abundance (ocean)
- 0.013 mg/L Compare Abundance (ocean) of all elements →
Crystal Structure
- Lattice constant a
- 502 pm
Electronic Structure
- Electrons per shell
- 2, 8, 18, 18, 8, 2 Compare Electrons per shell of all elements →
Identifiers
- CAS number
- 7440-39-3 Compare CAS number of all elements →
- Term symbol
- 1S0
- InChI
- InChI=1S/Ba
- InChI Key
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N
Electron Configuration Measured
Ba: 6s²[Xe] 6s²1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 6s²Atomic model
Isotopes change neutron count, mass, and stability — not the electron configuration of a neutral atom.
Schematic atomic model, not to scale.
Atomic Fingerprint
Emission / Absorption Spectrum
Isotope Distribution
| Mass number | Atomic mass (u) | Natural abundance | Half-life |
|---|---|---|---|
| 134 Stable | 133.90450818 ± 0.0000003 | 2.4170% | Stable |
| 135 Stable | 134.90568838 ± 0.00000029 | 6.5920% | Stable |
| 136 Stable | 135.90457573 ± 0.00000029 | 7.8540% | Stable |
| 137 Stable | 136.90582714 ± 0.0000003 | 11.2320% | Stable |
| 138 Stable | 137.905247 ± 0.00000031 | 71.6980% | Stable |
Phase / State
Reason: 701.9 °C below melting point (726.85 °C)
Schematic, not to scale
Phase transition points
Transition energies
Energy required to melt 1 mol at melting point
Energy required to vaporize 1 mol at boiling point
Energy required to sublime 1 mol at sublimation point
Density
At standard conditions
At standard conditions
Atomic Spectra
Showing 10 of 56. Sorted by ion charge (ascending).
Lines Holdings ?
| Ion | Charge | Total lines | Transition probabilities | Level designations |
|---|---|---|---|---|
| Ba I | 0 | 312 | 109 | 312 |
| Ba II | +1 | 112 | 94 | 112 |
| Ba III | +2 | 535 | 5 | 529 |
| Ba IV | +3 | 42 | 3 | 42 |
| Ba V | +4 | 135 | 0 | 126 |
| Ba VI | +5 | 138 | 0 | 127 |
| Ba VII | +6 | 70 | 0 | 70 |
| Ba VIII | +7 | 141 | 141 | 141 |
| Ba IX | +8 | 110 | 110 | 110 |
| Ba X | +9 | 31 | 31 | 31 |
Levels Holdings ?
| Ion | Charge | Levels |
|---|---|---|
| Ba I | 0 | 356 |
| Ba II | +1 | 162 |
| Ba III | +2 | 162 |
| Ba IV | +3 | 34 |
| Ba V | +4 | 52 |
| Ba VI | +5 | 50 |
| Ba VII | +6 | 32 |
| Ba VIII | +7 | 79 |
| Ba IX | +8 | 55 |
| Ba X | +9 | 30 |
Ionic Radii
| Charge | Coordination | Spin | Radius |
|---|---|---|---|
| +2 | 6 | N/A | 135 pm |
| +2 | 7 | N/A | 138 pm |
| +2 | 8 | N/A | 142 pm |
| +2 | 9 | N/A | 147 pm |
| +2 | 10 | N/A | 152 pm |
| +2 | 11 | N/A | 157 pm |
| +2 | 12 | N/A | 161 pm |
Compounds
Isotopes (5)
| Mass number | Atomic mass (u) | Natural abundance | Half-life | Decay mode | |
|---|---|---|---|---|---|
| 134 Stable | 133.90450818 ± 0.0000003 | 2.4170% ± 0.0180% | Stable | stable | |
| 135 Stable | 134.90568838 ± 0.00000029 | 6.5920% ± 0.0120% | Stable | stable | |
| 136 Stable | 135.90457573 ± 0.00000029 | 7.8540% ± 0.0240% | Stable | stable | |
| 137 Stable | 136.90582714 ± 0.0000003 | 11.2320% ± 0.0240% | Stable | stable | |
| 138 Stable | 137.905247 ± 0.00000031 | 71.6980% ± 0.0420% | Stable | stable |
Spectral Lines
Showing 50 of 92. Only spectral lines with measured intensity are shown by default.
| Wavelength (nm) | Intensity | Ion stage | Type | Transition | Accuracy | Source | |
|---|---|---|---|---|---|---|---|
| 392.686 nm | 25 | Ba III | emission | 5p5.(2P*<3/2>).6s 2[3/2]* → 5p5.(2P*<3/2>).6p 2[1/2] | Measured | NIST | |
| 399.306 nm | 25 | Ba III | emission | 5p5.(2P*<3/2>).6s 2[3/2]* → 5p5.(2P*<3/2>).6p 2[5/2] | Measured | NIST | |
| 381.3128 nm | 16 | Ba III | emission | 5p5.(2P*<1/2>).6s 2[1/2]* → 5p5.(2P*<1/2>).4f 2[5/2] | Measured | NIST | |
| 469.7428 nm | 15 | Ba III | emission | 5p5.(2P*<1/2>).5d 2[3/2]* → 5p5.(2P*<1/2>).6p 2[1/2] | Measured | NIST | |
| 448.1646 nm | 14 | Ba III | emission | 5p5.(2P*<1/2>).5d 2[3/2]* → 5p5.(2P*<3/2>).6p 2[5/2] | Measured | NIST | |
| 610.1987 nm | 13 | Ba III | emission | 5p5.(2P*<1/2>).5d 2[3/2]* → 5p5.(2P*<1/2>).4f 2[5/2] | Measured | NIST | |
| 389.6957 nm | 12 | Ba III | emission | 5p5.(2P*<3/2>).5d 2[5/2]* → 5p5.(2P*<3/2>).4f 2[3/2] | Measured | NIST | |
| 392.723 nm | 10 | Ba III | emission | 5p5.(2P*<3/2>).5d 2[5/2]* → 5p5.(2P*<3/2>).4f 2[9/2] | Measured | NIST | |
| 432.793 nm | 10 | Ba III | emission | 5p5.(2P*<3/2>).6s 2[3/2]* → 5p5.(2P*<3/2>).6p 2[1/2] | Measured | NIST | |
| 482.0642 nm | 10 | Ba III | emission | 5p5.(2P*<3/2>).5f 2[3/2] → 5p5.(2P*<3/2>).5g 2[5/2]* | Measured | NIST | |
| 485.0833 nm | 10 | Ba III | emission | 5p5.(2P*<3/2>).5f 2[3/2] → 5p5.(2P*<3/2>).5g 2[5/2]* | Measured | NIST | |
| 496.4038 nm | 10 | Ba III | emission | 5p5.(2P*<3/2>).5f 2[5/2] → 5p5.(2P*<3/2>).5g 2[7/2]* | Measured | NIST | |
| 504.9533 nm | 10 | Ba III | emission | 5p5.(2P*<3/2>).5f 2[5/2] → 5p5.(2P*<3/2>).5g 2[7/2]* | Measured | NIST | |
| 509.7537 nm | 10 | Ba III | emission | 5p5.(2P*<3/2>).5f 2[7/2] → 5p5.(2P*<3/2>).5g 2[9/2]* | Measured | NIST | |
| 513.4529 nm | 10 | Ba III | emission | 5p5.(2P*<3/2>).5f 2[7/2] → 5p5.(2P*<3/2>).5g 2[9/2]* | Measured | NIST | |
| 599.7996 nm | 10 | Ba III | emission | 5p5.(2P*<3/2>).7p 2[5/2] → 5p5.(2P*<3/2>).7d 2[7/2]* | Measured | NIST | |
| 637.7094 nm | 10 | Ba III | emission | 5p5.(2P*<3/2>).7p 2[3/2] → 5p5.(2P*<3/2>).7d 2[5/2]* | Measured | NIST | |
| 638.3756 nm | 10 | Ba III | emission | 5p5.(2P*<3/2>).7p 2[5/2] → 5p5.(2P*<3/2>).7d 2[7/2]* | Measured | NIST | |
| 438.5824 nm | 9 | Ba III | emission | 5p5.(2P*<1/2>).5d 2[5/2]* → 5p5.(2P*<3/2>).6p 2[5/2] | Measured | NIST | |
| 464.6207 nm | 9 | Ba III | emission | 5p5.(2P*<3/2>).5d 2[5/2]* → 5p5.(2P*<3/2>).4f 2[3/2] | Measured | NIST | |
| 542.699 nm | 9 | Ba III | emission | 5p5.(2P*<1/2>).5d 2[5/2]* → 5p5.(2P*<3/2>).6p 2[5/2] | Measured | NIST | |
| 491.7171 nm | 8 | Ba III | emission | 5p5.(2P*<1/2>).5f 2[7/2] → 5p5.(2P*<1/2>).5g 2[9/2]* | Measured | NIST | |
| 494.5436 nm | 8 | Ba III | emission | 5p5.(2P*<1/2>).5f 2[5/2] → 5p5.(2P*<1/2>).5g 2[7/2]* | Measured | NIST | |
| 495.2914 nm | 8 | Ba III | emission | 5p5.(2P*<1/2>).5f 2[5/2] → 5p5.(2P*<1/2>).5g 2[7/2]* | Measured | NIST | |
| 496.3235 nm | 8 | Ba III | emission | 5p5.(2P*<1/2>).5f 2[7/2] → 5p5.(2P*<1/2>).5g 2[9/2]* | Measured | NIST | |
| 503.3498 nm | 8 | Ba III | emission | 5p5.(2P*<3/2>).7p 2[5/2] → 5p5.(2P*<3/2>).5g 2[5/2]* | Measured | NIST | |
| 503.7341 nm | 8 | Ba III | emission | 5p5.(2P*<1/2>).5d 2[3/2]* → 5p5.(2P*<1/2>).6p 2[1/2] | Measured | NIST | |
| 590.0288 nm | 8 | Ba III | emission | 5p5.(2P*<3/2>).5f 2[9/2] → 5p5.(2P*<3/2>).7d 2[7/2]* | Measured | NIST | |
| 601.6412 nm | 8 | Ba III | emission | 5p5.(2P*<1/2>).5d 2[3/2]* → 5p5.(2P*<1/2>).6p 2[3/2] | Measured | NIST | |
| 603.6589 nm | 8 | Ba III | emission | 5p5.(2P*<3/2>).5f 2[5/2] → 5p5.(2P*<3/2>).7d 2[7/2]* | Measured | NIST | |
| 607.7807 nm | 8 | Ba III | emission | 5p5.(2P*<3/2>).6s 2[3/2]* → 5p5.(2P*<3/2>).4f 2[3/2] | Measured | NIST | |
| 627.0084 nm | 8 | Ba III | emission | 5p5.(2P*<3/2>).7p 2[3/2] → 5p5.(2P*<3/2>).7d 2[5/2]* | Measured | NIST | |
| 652.6166 nm | 8 | Ba III | emission | 5p5.(2P*<3/2>).7p 2[5/2] → 5p5.(2P*<3/2>).8s 2[3/2]* | Measured | NIST | |
| 709.5497 nm | 8 | Ba III | emission | 5p5.(2P*<3/2>).6s 2[3/2]* → 5p5.(2P*<3/2>).4f 2[3/2] | Measured | NIST | |
| 519.6426 nm | 7 | Ba III | emission | 5p5.(2P*<3/2>).7p 2[5/2] → 5p5.(2P*<3/2>).5g 2[7/2]* | Measured | NIST | |
| 552.8138 nm | 7 | Ba III | emission | 5p5.(2P*<1/2>).5d 2[3/2]* → 5p5.(2P*<3/2>).6p 2[1/2] | Measured | NIST | |
| 574.0413 nm | 7 | Ba III | emission | 5p5.(2P*<3/2>).5f 2[3/2] → 5p5.(2P*<3/2>).7d 2[7/2]* | Measured | NIST | |
| 579.8254 nm | 7 | Ba III | emission | 5p5.(2P*<3/2>).5f 2[5/2] → 5p5.(2P*<3/2>).7d 2[5/2]* | Measured | NIST | |
| 585.9192 nm | 7 | Ba III | emission | 5p5.(2P*<3/2>).7p 2[5/2] → 5p5.(2P*<3/2>).7d 2[5/2]* | Measured | NIST | |
| 588.1879 nm | 7 | Ba III | emission | 5p5.(2P*<3/2>).5f 2[9/2] → 5p5.(2P*<3/2>).7d 2[7/2]* | Measured | NIST | |
| 598.3721 nm | 7 | Ba III | emission | 5p5.(2P*<3/2>).7p 2[1/2] → 5p5.(2P*<3/2>).7d 2[1/2]* | Measured | NIST | |
| 658.3333 nm | 7 | Ba III | emission | 5p5.(2P*<3/2>).7p 2[3/2] → 5p5.(2P*<3/2>).7d 2[3/2]* | Measured | NIST | |
| 565.8601 nm | 6 | Ba III | emission | 5p5.(2P*<1/2>).5d 2[5/2]* → 5p5.(2P*<3/2>).4f 2[7/2] | Measured | NIST | |
| 569.7415 nm | 6 | Ba III | emission | 5p5.(2P*<3/2>).5f 2[3/2] → 5p5.(2P*<3/2>).7d 2[3/2]* | Measured | NIST | |
| 571.6614 nm | 6 | Ba III | emission | 5p5.(2P*<3/2>).7p 2[1/2] → 5p5.(2P*<3/2>).7d 2[3/2]* | Measured | NIST | |
| 572.6169 nm | 6 | Ba III | emission | 5p5.(2P*<3/2>).7p 2[3/2] → 5p5.(2P*<3/2>).7d 2[3/2]* | Measured | NIST | |
| 581.3545 nm | 6 | Ba III | emission | 5p5.(2P*<3/2>).5f 2[3/2] → 5p5.(2P*<3/2>).7d 2[1/2]* | Measured | NIST | |
| 607.6665 nm | 6 | Ba III | emission | 5p5.(2P*<3/2>).5f 2[7/2] → 5p5.(2P*<3/2>).7d 2[5/2]* | Measured | NIST | |
| 613.1372 nm | 6 | Ba III | emission | 5p5.(2P*<3/2>).7p 2[5/2] → 5p5.(2P*<3/2>).7d 2[1/2]* | Measured | NIST | |
| 640.614 nm | 6 | Ba III | emission | 5p5.(2P*<3/2>).7p 2[1/2] → 5p5.(2P*<3/2>).7d 2[3/2]* | Measured | NIST |
Extended Properties
Covalent Radii (Extended)
- Covalent radius (Pyykkö)
- 196 pm
- Covalent radius (Pyykkö, double)
- 161 pm
- Covalent radius (Pyykkö, triple)
- 149 pm
- Covalent radius (Bragg)
- 210 pm
Van der Waals Radii
- Truhlar
- 268 pm
- Batsanov
- 270 pm
- Alvarez
- 303 pm
- UFF
- 370.3 pm
- MM3
- 307 pm
Atomic & Metallic Radii
- Atomic radius (Rahm)
- 293 pm
- Metallic radius (C12)
- 222 pm
Numbering Scales
- Mendeleev
- 9
- Pettifor
- 14
- Glawe
- 14
Electronegativity Scales
- Ghosh
- 0
- Miedema
- 2
- Gunnarsson–Lundqvist
- 3
- Robles–Bartolotti
- 2
Polarizability & Dispersion
- Dipole polarizability
- 272 a.u.
- Dipole polarizability (unc.)
- 10 a.u.
- C₆ (Gould–Bučko)
- 5540 Ha·Bohr6
Miedema Parameters
- Miedema molar volume
- 38.1 cm3/mol
- Miedema electron density
- 1
Supply Risk & Economics
- Production concentration
- 44
- Relative supply risk
- 8
- Reserve distribution
- 42
- Political stability (top producer)
- 24
- Political stability (top reserve)
- 24
Phase Transitions & Allotropes
| Melting point | 1000.15 K |
| Boiling point | 2118.15 K |
Oxidation State Categories
Advanced Reference Data
Screening Constants (12)
| n | Orbital | σ |
|---|---|---|
| 1 | s | 1.1139 |
| 2 | p | 4.1904 |
| 2 | s | 14.7532 |
| 3 | d | 13.9757 |
| 3 | p | 18.6836 |
| 3 | s | 18.8444 |
| 4 | d | 32.216 |
| 4 | p | 29.1968 |
| 4 | s | 28.08 |
| 5 | p | 41.1995 |
Crystal Radii Detail (7)
| Charge | CN | Spin | rcrystal (pm) | Origin |
|---|---|---|---|---|
| 2 | VI | 149 | ||
| 2 | VII | 152 | calculated, | |
| 2 | VIII | 156 | ||
| 2 | IX | 161 | ||
| 2 | X | 166 | ||
| 2 | XI | 171 | ||
| 2 | XII | 175 | calculated, |
Isotope Decay Modes (55)
| Isotope | Mode | Intensity |
|---|---|---|
| 113 | p | — |
| 113 | A | — |
| 114 | B+ | 100% |
| 114 | B+p | 20% |
| 114 | A | 0.9% |
| 114 | 12C | 0% |
| 115 | B+ | 100% |
| 115 | B+p | 15% |
| 116 | B+ | 100% |
| 116 | B+p | 3% |
X‑ray Scattering Factors (508)
| Energy (eV) | f₁ | f₂ |
|---|---|---|
| 10 | — | 0.10258 |
| 10.1617 | — | 0.10761 |
| 10.3261 | — | 0.11287 |
| 10.4931 | — | 0.1184 |
| 10.6628 | — | 0.1242 |
| 10.8353 | — | 0.13028 |
| 11.0106 | — | 0.13666 |
| 11.1886 | — | 0.14335 |
| 11.3696 | — | 0.15037 |
| 11.5535 | — | 0.15773 |
Additional Data
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
4.25×102 milligrams per kilogram
References (1)
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
1.3×10-2 milligrams per liter
References (1)
Sources
Sources of this element.
It is found only in combination with other elements, chiefly with sulfate and carbonate and is prepared by electrolysis of the chloride.
References (1)
- [6] Barium https://periodic.lanl.gov/56.shtml
References
(9)
Data deposited in or computed by PubChem
The half-life and atomic mass data was provided by the Atomic Mass Data Center at the International Atomic Energy Agency.
Element data are cited from the Atomic weights of the elements (an IUPAC Technical Report). The IUPAC periodic table of elements can be found at https://iupac.org/what-we-do/periodic-table-of-elements/. Additional information can be found within IUPAC publication doi:10.1515/pac-2015-0703 Copyright © 2020 International Union of Pure and Applied Chemistry.
The information are cited from Pure Appl. Chem. 2018; 90(12): 1833-2092, https://doi.org/10.1515/pac-2015-0703.
Thomas Jefferson National Accelerator Facility (Jefferson Lab) is one of 17 national laboratories funded by the U.S. Department of Energy. The lab's primary mission is to conduct basic research of the atom's nucleus using the lab's unique particle accelerator, known as the Continuous Electron Beam Accelerator Facility (CEBAF). For more information visit https://www.jlab.org/
The periodic table at the LANL (Los Alamos National Laboratory) contains basic element information together with the history, source, properties, use, handling and more. The provenance data may be found from the link under the source name.
The periodic table contains NIST's critically-evaluated data on atomic properties of the elements. The provenance data that include data for atomic spectroscopy, X-ray and gamma ray, radiation dosimetry, nuclear physics, and condensed matter physics may be found from the link under the source name. Ref: https://www.nist.gov/pml/atomic-spectra-database
This section provides all form of data related to element Barium.
The element property data was retrieved from publications.