Chromium (Cr)
transition-metalSolid
Standard Atomic Weight
51.9961 uElectron configuration
[Ar] 3d5 4s1Melting point
1906.85 °CBoiling point
2670.85 °CDensity
7150 kg/m³Oxidation states
−4, −2, −1, 0, +1, +2, +3, +4, +5, +6Electronegativity (Pauling)
1.66Ionization energy (1st)
6.76651 eVDiscovery year
1797Atomic radius
140 pmDetails
Chromium is a hard transition metal best known for forming adherent, protective oxide films and for giving many minerals and compounds strong colors. It occurs mainly in chromite ores and is an important alloying element in stainless and heat-resisting steels. Its chemistry spans several oxidation states, especially +3 and +6, with a sharp contrast between relatively stable Cr(III) compounds and strongly oxidizing, often toxic Cr(VI) species.
Chromium is used extensively in automobile trim as chromium metal because of its shiny finish and corrosion resistance.
The name derives from the Greek chroma for "colour", from the many coloured compounds of chromium. It was discovered in 1797 by the French chemist and pharmacist Nicolas-Louis Vauquelin, who also isolated chromium in 1798.
Chromium was discovered by Louis-Nicholas Vauquelin while experimenting with a material known as Siberian red lead, also known as the mineral crocoite (PbCrO4), in 1797. He produced chromium oxide (CrO3) by mixing crocoite with hydrochloric acid (HCl). Although he believed a method for isolating chromium didn't yet exist, Vauquelin was pleasantly surprised in 1798 to discover that he was able to obtain metallic chromium by simply heating chromium oxide in a charcoal oven. Today, chromium is primarily obtained by heating the mineral chromite (FeCr2O4) in the presence of aluminum or silicon.
From the Greek word chroma, color. Chromium is a steel-gray, lustrous, hard metal that takes a high polish. Discovered in 1797 by the Frenchman Louis Nicolas Vauquelin.
Pure chromium is a lustrous, silvery-gray metal with a high polish and a relatively high melting point. It is hard and brittle at room temperature, and its surface is rapidly passivated by a very thin oxide layer that resists further corrosion under many conditions.
The largest use of chromium is in ferrochrome for stainless steel, where chromium provides corrosion resistance by forming a passive surface film. It is also used in tool steels, superalloys, wear-resistant coatings, and hard chromium electroplating. Chromium compounds have been used in pigments, leather tanning, wood preservation, catalysts, and refractory materials, although several Cr(VI)-based uses have been restricted or replaced because of toxicity and environmental persistence.
Chromium is a blue-white metal that is hard, brittle and very corrosion resistant. Chromium can be polished to form a very shiny surface and is often plated to other metals to form a protective and attractive covering. Chromium is added to steel to harden it and to form stainless steel, a steel alloy that contains at least 10% chromium. Other chromium-steel alloys are used to make armor plate, safes, ball bearings and cutting tools.
Chromium forms many colorful compounds that have industrial uses. Lead chromate (PbCrO4), also known as chrome yellow, has been used as a yellow pigment in paints. Chromic oxide (Cr2O3), also known as chrome green, is the ninth most abundant compound in the earth's crust and is a widely used green pigment. Rubies and emeralds also owe their colors to chromium compounds. Potassium dichromate (K2Cr2O7) is used in the tanning of leather while other chromium compounds are used as mordants, materials which permanently fix dyes to fabrics. Chromium compounds are also used to anodize aluminum, a process which coats aluminum with a thick, protective layer of oxide. Chromite, chromium's primary ore, is used to make molds for the firing of bricks because of its high melting point, moderate thermal expansion and stable crystal structure.
Chromium is used to harden steel, manufacture stainless steel, and form many useful alloys. It is mostly used in plating to produce a hard, beautiful surface and to prevent corrosion. Chromium gives glass an emerald green color and is widely used as a catalyst.
The refractory industry uses chromite for forming bricks and shapes, as it has a high melting point, moderate thermal expansion, and stability of crystalline structure.
Isotopes in Earth/Planetary Science
Molecules, atoms, and ions of the stable isotopes of chromium possess slightly different physical and chemical properties, and they commonly will be fractionated during physical, chemical, and biological processes, giving rise to variations in isotopic abundances and in atomic weights. There are measureable variations in the isotopic abundances of chromium in natural terrestrial materials (Fig. IUPAC.24.1).
SiC grains are formed in very high-temperature events that occurred before the formation of the Solar System. The chemical and isotopic composition of certain elements in these grains, such as chromium, provides insights into the origin of the Solar System. The 54Cr nucleus is only produced by supernovae. Excess amounts of this isotope in the SiC grains (relative to terrestrial isotopic composition) in primitive meteorites suggest a heterogeneous distribution of 54Cr in the early Solar System and different sources of material to our Solar System [206] L. Qin, L. R. Nittler, C. M. O. D. Alexander, J. Wang, F. J. Stadermann, R. W. Carlson. Geochim. Cosmochim. Acta.75, 629 (2010).. The early solar nebula was divided into two components. One contained chromium depleted in the lighter isotopes and the other contained heavier chromium isotopes. Isotopic studies indicate these components formed a homogeneous mixture in the early Earth, but they separated during partitioning of the Earth’s core (Fig. IUPAC.24.1) [207] F. Moynier, Q. Z. Yin, E. Schauble. Science331, 1417 (2011)., [208] W. F. McDonough. Science331, 1397 (2011)..
Mobility and toxicity of chromium metal depend largely on the oxidation state of the element. Isotopes of chromium are fractionated by reduction-oxidation (redox) chemical reactions. The isotopic composition has been used to trace the origin of the element in the environment and provide information on reduction-oxidation chemical processes [209] A. S. Ellis, T. M. Johnson, T. D. Bullen. Science295, 2060 (2002)..
Isotopes in Medicine
Stable isotopes of chromium are used to investigate the metabolism of chromium (III), which is an essential nutrient. Chromium stable isotopes (53Cr and 54Cr) have been administered to patients and the relative metabolic activity of each isotope is measured to study insulin function in patients suffering from diabetes (a disease in which the body is unable to produce any or enough insulin, and/or is not able to properly use the insulin that it does produce, resulting in elevated levels of glucose in the blood) [210] H. M. Silver, M. A. Seebeck, R. M. Cowett, K. Y. Patterson, C. Veillon. J. Soc. Gynecol. Investig.4, 254 (1997).. 51Cr and 53Cr have been used to label red blood cells to determine blood volume and life-time of red blood cells in the body [210] H. M. Silver, M. A. Seebeck, R. M. Cowett, K. Y. Patterson, C. Veillon. J. Soc. Gynecol. Investig.4, 254 (1997)..
Chromium forms compounds in oxidation states from negative values in organometallic chemistry to +6, but +3 and +6 dominate common inorganic chemistry. Chromium(III) oxide, Cr₂O₃, is a stable green solid and an important pigment and refractory material. Chromium(VI) oxide, CrO₃, chromates such as potassium chromate, K₂CrO₄, and dichromates such as potassium dichromate, K₂Cr₂O₇, are strong oxidants. Chromium(II) chloride, CrCl₂, is a reducing Cr(II) salt used in specialized synthesis.
All compounds of chromium are colored. The most important chromates are those of sodium and potassium, the dichromates, and the potassium and ammonium chrome alums. The dichromates are used as oxidizing agents in quantitative analysis, also in tanning leather.
Other compounds are of industrial value; lead chromate is chrome yellow, a valued pigment. Chromium compounds are used in the textile industry as mordants, and by the aircraft and other industries for anodizing aluminum.
See more information at the Chromium compound page.
Metallic chromium is not highly reactive in bulk form, but dusts and fumes from welding, grinding, or plating operations can be hazardous. Soluble Cr(VI) compounds are toxic, corrosive, sensitizing, and carcinogenic by inhalation, and they require strict exposure control. Cr(III) compounds are generally less mobile and less toxic, although concentrated salts and fine powders still present chemical and occupational hazards.
Chromium compounds are toxic and should be handled with proper safeguards.
Chromium is a natural trace constituent of rocks, soils, and sediments, commonly associated with ultramafic rocks and chromite minerals. In the environment, Cr(III) tends to form insoluble hydroxides and complexes with organic matter, while Cr(VI) oxyanions are more mobile in oxygenated waters. Industrial releases from plating, tanning, pigment manufacture, and waste disposal have produced localized contamination where redox conditions control persistence and transport.
Chromium is produced chiefly by mining chromite ore and reducing it to ferrochrome for steelmaking. South Africa, Kazakhstan, India, Turkey, and several other countries are important sources of chromite, so supply is tied to ore quality, energy costs, and metallurgical capacity. Demand is dominated by stainless steel production, with smaller markets for chemicals, refractories, and plating. Recycling occurs mainly through stainless steel and alloy scrap, which returns chromium to steel production and reduces dependence on primary ore.
The principal ore is chromite, which is found in Zimbabwe, Russia, New Zealand, Turkey, Iran, Albania, Finland, Democratic Republic of Madagascar, and the Phillippines. The metal is usually produced by reducing the oxide with aluminum.
Chromium is a minor but widespread element in the cosmos, made mainly in massive stars and supernova nucleosynthesis near the iron peak. It is present in the Sun, meteorites, and rocky planetary materials. Isotopic ratios of chromium in meteorites are used in cosmochemistry to trace early Solar System reservoirs and nucleosynthetic contributions.
- The name chromium comes from the Greek word for color, reflecting its vividly colored compounds.
- Ruby owes its red color to trace Cr³⁺ substituting for aluminum in corundum.
- Chrome plating can be decorative, but engineering hard chrome is used mainly for wear resistance.
- Passivation by chromium oxide is the key reason stainless steel does not behave like ordinary carbon steel.
- Lead chromate, PbCrO₄, was once a major yellow pigment but is now restricted in many applications.
- Chromium metal is usually traded through ferrochrome rather than as pure metal.
Images
Properties
Physical
- Atomic radius (empirical)
- 140 pm Compare Atomic radius (empirical) of all elements →
- Covalent radius
- 139 pm Compare Covalent radius of all elements →
- Van der Waals radius
- 189 pm Compare Van der Waals radius of all elements →
- Metallic radius
- 119 pm Compare Metallic radius of all elements →
- Density
- 7150 kg/m³ Compare Density of all elements →
- Molar volume
- 0.00723 L/mol
- Phase at STP
- Solid Compare Phase at STP of all elements →
- Melting point
- 1906.85 °C Compare Melting point of all elements →
- Boiling point
- 2670.85 °C Compare Boiling point of all elements →
- Thermal conductivity
- 93.9 W/(m·K) Compare Thermal conductivity of all elements →
- Specific heat capacity
- 0.449 J/(g·K) Compare Specific heat capacity of all elements →
- Molar heat capacity
- 23.35 J/(mol·K) Compare Molar heat capacity of all elements →
- Crystal structure
- Body-centered cubic Compare Crystal structure of all elements →
Chemical
- Electronegativity (Pauling)
- 1.66 Compare Electronegativity (Pauling) of all elements →
- Electronegativity (Allen)
- 1.65
- Electron affinity
- 0.675 eV
- Ionization energy (1st)
- 6.76651 eV Compare Ionization energy (1st) of all elements →
- Ionization energy (2nd)
- 16.486362 eV Compare Ionization energy (2nd) of all elements →
- Ionization energy (3rd)
- 30.959107 eV Compare Ionization energy (3rd) of all elements →
- Ionization energy (4th)
- 49.160169 eV Compare Ionization energy (4th) of all elements →
- Ionization energy (5th)
- 69.460239 eV Compare Ionization energy (5th) of all elements →
- Oxidation states
- −4, −2, −1, 0, +1, +2, +3, +4, +5, +6 Compare Oxidation states of all elements →
- Valence electrons
- 6 Compare Valence electrons of all elements →
- Electron configuration
- [Ar] 3d5 4s1
Thermodynamic
- Heat of fusion
- 0.21246826 eV Compare Heat of fusion of all elements →
- Heat of vaporization
- 3.518682 eV Compare Heat of vaporization of all elements →
- Heat of sublimation
- 4.119811 eV
- Heat of atomization
- 4.119811 eV
- Atomization enthalpy
- 4.119604 eV
Nuclear
- Protons
- 24 Compare Protons of all elements →
- Neutrons
- 28 Compare Neutrons of all elements →
- Known isotopes
- 30 Compare Known isotopes of all elements →
- Stable isotopes
- 3 Compare Stable isotopes of all elements →
- Most stable isotope
- Cr-52
- Discovery year
- 1797
Abundance
- Abundance (Earth's crust)
- 102 mg/kg Compare Abundance (Earth's crust) of all elements →
- Abundance (ocean)
- 3 × 10−4 mg/L Compare Abundance (ocean) of all elements →
Crystal Structure
- Lattice constant a
- 288 pm
Electronic Structure
- Electrons per shell
- 2, 8, 13, 1 Compare Electrons per shell of all elements →
Identifiers
- CAS number
- 7440-47-3 Compare CAS number of all elements →
- Term symbol
- 7S3
- InChI
- InChI=1S/Cr
- InChI Key
- VYZAMTAEIAYCRO-UHFFFAOYSA-N
Electron Configuration Measured
Cr: 3d⁵ 4s¹[Ar] 3d⁵ 4s¹1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁵ 4s¹Atomic 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 |
|---|---|---|---|
| 52 Stable | 51.94050623 ± 0.00000063 | 83.7890% | Stable |
| 53 Stable | 52.94064815 ± 0.00000062 | 9.5010% | Stable |
| 54 Stable | 53.93887916 ± 0.00000061 | 2.3650% | Stable |
Phase / State
Reason: 1881.8 °C below melting point (1906.85 °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 24. Sorted by ion charge (ascending).
Lines Holdings ?
| Ion | Charge | Total lines | Transition probabilities | Level designations |
|---|---|---|---|---|
| Cr I | 0 | 4369 | 527 | 4369 |
| Cr II | +1 | 5370 | 92 | 5370 |
| Cr III | +2 | 136 | 0 | 0 |
| Cr IV | +3 | 188 | 102 | 102 |
| Cr V | +4 | 193 | 104 | 193 |
| Cr VI | +5 | 102 | 26 | 102 |
| Cr VII | +6 | 143 | 4 | 143 |
| Cr VIII | +7 | 36 | 9 | 36 |
| Cr IX | +8 | 58 | 18 | 58 |
| Cr X | +9 | 75 | 46 | 75 |
Levels Holdings ?
| Ion | Charge | Levels |
|---|---|---|
| Cr I | 0 | 659 |
| Cr II | +1 | 914 |
| Cr III | +2 | 215 |
| Cr IV | +3 | 155 |
| Cr V | +4 | 47 |
| Cr VI | +5 | 63 |
| Cr VII | +6 | 66 |
| Cr VIII | +7 | 34 |
| Cr IX | +8 | 49 |
| Cr X | +9 | 39 |
Ionic Radii
| Charge | Coordination | Spin | Radius |
|---|---|---|---|
| +2 | 6 | low | 73 pm |
| +2 | 6 | high | 80 pm |
| +3 | 6 | N/A | 61.5 pm |
| +4 | 4 | N/A | 41 pm |
| +4 | 6 | N/A | 55.00000000000001 pm |
| +5 | 4 | N/A | 34.5 pm |
| +5 | 6 | N/A | 49 pm |
| +5 | 8 | N/A | 56.99999999999999 pm |
| +6 | 4 | N/A | 26 pm |
| +6 | 6 | N/A | 44 pm |
Compounds
Isotopes (3)
| Mass number | Atomic mass (u) | Natural abundance | Half-life | Decay mode | |
|---|---|---|---|---|---|
| 52 Stable | 51.94050623 ± 0.00000063 | 83.7890% ± 0.0180% | Stable | stable | |
| 53 Stable | 52.94064815 ± 0.00000062 | 9.5010% ± 0.0170% | Stable | stable | |
| 54 Stable | 53.93887916 ± 0.00000061 | 2.3650% ± 0.0070% | Stable | stable |
Spectral Lines
Showing 50 of 2531. Only spectral lines with measured intensity are shown by default.
| Wavelength (nm) | Intensity | Ion stage | Type | Transition | Accuracy | Source | |
|---|---|---|---|---|---|---|---|
| 540.978408 nm | 8500 | Cr I | emission | 3d4.4s2 a 5D → 3d5.(6S).4p z 5P* | Measured | NIST | |
| 534.57965 nm | 5100 | Cr I | emission | 3d4.4s2 a 5D → 3d5.(6S).4p z 5P* | Measured | NIST | |
| 529.827202 nm | 3540 | Cr I | emission | 3d4.4s2 a 5D → 3d5.(6S).4p z 5P* | Measured | NIST | |
| 435.17622 nm | 3500 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5F* | Measured | NIST | |
| 534.83147 nm | 3200 | Cr I | emission | 3d4.4s2 a 5D → 3d5.(6S).4p z 5P* | Measured | NIST | |
| 434.450128 nm | 3100 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5F* | Measured | NIST | |
| 433.944609 nm | 2600 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5F* | Measured | NIST | |
| 526.415341 nm | 2600 | Cr I | emission | 3d4.4s2 a 5D → 3d5.(6S).4p z 5P* | Measured | NIST | |
| 464.616212 nm | 2400 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) y 5P* | Measured | NIST | |
| 529.669109 nm | 2100 | Cr I | emission | 3d4.4s2 a 5D → 3d5.(6S).4p z 5P* | Measured | NIST | |
| 391.915844 nm | 2030 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5D* | Measured | NIST | |
| 433.755701 nm | 1900 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5F* | Measured | NIST | |
| 740.01798 nm | 1900 | Cr I | emission | 3d5.(6S).4p z 7P* → 3d5.(6S).5s e 7S | Measured | NIST | |
| 465.215743 nm | 1750 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) y 5P* | Measured | NIST | |
| 435.962444 nm | 1420 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5F* | Measured | NIST | |
| 437.127465 nm | 1400 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5F* | Measured | NIST | |
| 735.58903 nm | 1400 | Cr I | emission | 3d5.(6S).4p z 7P* → 3d5.(6S).5s e 7S | Measured | NIST | |
| 461.612404 nm | 1360 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) y 5P* | Measured | NIST | |
| 390.875593 nm | 1310 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5D* | Measured | NIST | |
| 449.685195 nm | 1300 | Cr I | emission | 3d5.(6S).4s a 5S → 3d4.(5D).4s.4p.(3P*) y 5P* | Measured | NIST | |
| 524.756509 nm | 1250 | Cr I | emission | 3d4.4s2 a 5D → 3d5.(6S).4p z 5P* | Measured | NIST | |
| 460.074835 nm | 1190 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) y 5P* | Measured | NIST | |
| 433.971051 nm | 1120 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5F* | Measured | NIST | |
| 462.617342 nm | 1100 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) y 5P* | Measured | NIST | |
| 435.104951 nm | 1080 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5F* | Measured | NIST | |
| 438.4975 nm | 1060 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5F* | Measured | NIST | |
| 526.571497 nm | 1050 | Cr I | emission | 3d4.4s2 a 5D → 3d5.(6S).4p z 5P* | Measured | NIST | |
| 452.64538 nm | 960 | Cr I | emission | 3d5.(4G).4s a 5G → 3d5.(4G).4p z 5G* | Measured | NIST | |
| 454.595302 nm | 930 | Cr I | emission | 3d5.(6S).4s a 5S → 3d4.(5D).4s.4p.(3P*) y 5P* | Measured | NIST | |
| 532.832346 nm | 930 | Cr I | emission | 3d5.(6S).4p z 7P* → 3d5.(6S).4d e 7D | Measured | NIST | |
| 388.32867 nm | 910 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5D* | Measured | NIST | |
| 392.86372 nm | 880 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5D* | Measured | NIST | |
| 388.521354 nm | 810 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5D* | Measured | NIST | |
| 746.23079 nm | 800 | Cr I | emission | 3d5.(6S).4p z 7P* → 3d5.(6S).5s e 7S | Measured | NIST | |
| 453.073802 nm | 770 | Cr I | emission | 3d5.(4G).4s a 5G → 3d5.(4G).4p z 5G* | Measured | NIST | |
| 388.679508 nm | 740 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5D* | Measured | NIST | |
| 392.102067 nm | 740 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5D* | Measured | NIST | |
| 394.148757 nm | 720 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5D* | Measured | NIST | |
| 697.83983 nm | 640 | Cr I | emission | 3d4.(5D).4s.4p.(3P*) y 7P* → 3d5.(6S).4d e 7D | Measured | NIST | |
| 396.3684 nm | 620 | Cr I | emission | 3d5.(4G).4s a 5G → 3d5.(4G).4p y 5H* | Measured | NIST | |
| 453.569676 nm | 600 | Cr I | emission | 3d5.(4G).4s a 5G → 3d5.(4G).4p z 5G* | Measured | NIST | |
| 390.290908 nm | 590 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5D* | Measured | NIST | |
| 455.864413 nm | 590 | Cr II | emission | 3d5 b 4F → 3d4.(5D).4p z 4D* | Measured | NIST | |
| 461.335727 nm | 590 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) y 5P* | Measured | NIST | |
| 396.974253 nm | 570 | Cr I | emission | 3d5.(4G).4s a 5G → 3d5.(4G).4p y 5H* | Measured | NIST | |
| 458.004789 nm | 560 | Cr I | emission | 3d5.(6S).4s a 5S → 3d4.(5D).4s.4p.(3P*) y 5P* | Measured | NIST | |
| 530.074563 nm | 530 | Cr I | emission | 3d4.4s2 a 5D → 3d5.(6S).4p z 5P* | Measured | NIST | |
| 397.665859 nm | 520 | Cr I | emission | 3d5.(4G).4s a 5G → 3d5.(4G).4p y 5H* | Measured | NIST | |
| 454.04987 nm | 500 | Cr I | emission | 3d5.(4G).4s a 5G → 3d5.(4G).4p z 5G* | Measured | NIST | |
| 459.139098 nm | 490 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) y 5P* | Measured | NIST |
Extended Properties
Covalent Radii (Extended)
- Covalent radius (Pyykkö)
- 122 pm
- Covalent radius (Pyykkö, double)
- 111 pm
- Covalent radius (Pyykkö, triple)
- 103 pm
- Covalent radius (Bragg)
- 140 pm
Van der Waals Radii
- Batsanov
- 205 pm
- Alvarez
- 245 pm
- UFF
- 302.3 pm
- MM3
- 225 pm
Atomic & Metallic Radii
- Atomic radius (Rahm)
- 233 pm
- Metallic radius (C12)
- 128 pm
Numbering Scales
- Mendeleev
- 51
- Pettifor
- 57
- Glawe
- 55
Electronegativity Scales
- Ghosh
- 0
- Miedema
- 5
- Gunnarsson–Lundqvist
- 4
- Robles–Bartolotti
- 2
Polarizability & Dispersion
- Dipole polarizability
- 83 a.u.
- Dipole polarizability (unc.)
- 12 a.u.
- C₆
- 602 Ha·Bohr6
- C₆ (Gould–Bučko)
- 709 Ha·Bohr6
Chemical Affinity
- Proton affinity
- 791.3 kJ/mol
- Gas basicity
- 768.4 kJ/mol
Miedema Parameters
- Miedema molar volume
- 7.23 cm3/mol
- Miedema electron density
- 5
Supply Risk & Economics
- Production concentration
- 37
- Relative supply risk
- 6
- Reserve distribution
- 46
- Political stability (top producer)
- 44
- Political stability (top reserve)
- 62
Phase Transitions & Allotropes
| Melting point | 2180.15 K |
| Boiling point | 2944.15 K |
Oxidation State Categories
Advanced Reference Data
Screening Constants (7)
| n | Orbital | σ |
|---|---|---|
| 1 | s | 0.5862 |
| 2 | p | 3.9248 |
| 2 | s | 7.0162 |
| 3 | d | 14.2434 |
| 3 | p | 12.534 |
| 3 | s | 11.6322 |
| 4 | s | 18.8668 |
Crystal Radii Detail (10)
| Charge | CN | Spin | rcrystal (pm) | Origin |
|---|---|---|---|---|
| 2 | VI | LS | 87 | estimated, |
| 2 | VI | HS | 94 | from r^3 vs V plots, |
| 3 | VI | 75.5 | from r^3 vs V plots, | |
| 4 | IV | 55 | ||
| 4 | VI | 69 | from r^3 vs V plots, | |
| 5 | IV | 48.5 | from r^3 vs V plots, | |
| 5 | VI | 63 | estimated, from r^3 vs V plots, | |
| 5 | VIII | 71 | ||
| 6 | IV | 40 | ||
| 6 | VI | 58 | calculated, |
Isotope Decay Modes (52)
| Isotope | Mode | Intensity |
|---|---|---|
| 41 | p | — |
| 42 | B+ | 100% |
| 42 | B+p | 94.4% |
| 42 | 2p | — |
| 43 | B+ | 100% |
| 43 | B+p | 79.3% |
| 43 | 2p | 11.6% |
| 43 | 3p | 0.1% |
| 43 | B+A | — |
| 44 | B+ | 100% |
X‑ray Scattering Factors (751)
| Energy (eV) | f₁ | f₂ |
|---|---|---|
| 0.42 | -0.0076 | 0.02756 |
| 0.46 | -0.01 | 0.03022 |
| 0.5 | -0.0123 | 0.03301 |
| 0.54 | -0.0148 | 0.03586 |
| 0.58 | -0.0176 | 0.03897 |
| 0.62 | -0.0202 | 0.04225 |
| 0.66 | -0.0225 | 0.04515 |
| 0.7 | -0.0257 | 0.04771 |
| 0.74 | -0.0292 | 0.05056 |
| 0.78 | -0.0332 | 0.05331 |
Additional Data
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
1.02×102 milligrams per kilogram
References (1)
- [5] Chromium https://education.jlab.org/itselemental/ele024.html
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
3×10-4 milligrams per liter
References (1)
- [5] Chromium https://education.jlab.org/itselemental/ele024.html
Sources
Sources of this element.
The principal ore is chromite, which is found in Zimbabwe, Russia, New Zealand, Turkey, Iran, Albania, Finland, Democratic Republic of Madagascar, and the Phillippines. The metal is usually produced by reducing the oxide with aluminum.
References (1)
- [6] Chromium https://periodic.lanl.gov/24.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 Chromium.
The element property data was retrieved from publications.