Chromium (Cr)
transition-metalSolid
Peso atomico standard
51,9961 uConfigurazione elettronica
[Ar] 3d5 4s1Punto di fusione
1906,85 °CPunto di ebollizione
2670,85 °CDensità
7150 kg/m³Stati di ossidazione
−4, −2, −1, 0, +1, +2, +3, +4, +5, +6Elettronegatività (Pauling)
1,66Energia di ionizzazione (1ª)
6,76651 eVAnno della scoperta
1797Raggio atomico
140 pmDettagli
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.
Immagini
Proprietà
Fisiche
- Raggio atomico (empirico)
- 140 pm Confronta Raggio atomico (empirico) di tutti gli elementi →
- Raggio covalente
- 139 pm Confronta Raggio covalente di tutti gli elementi →
- Raggio di van der Waals
- 189 pm Confronta Raggio di van der Waals di tutti gli elementi →
- Raggio metallico
- 119 pm Confronta Raggio metallico di tutti gli elementi →
- Densità
- 7150 kg/m³ Confronta Densità di tutti gli elementi →
- Volume molare
- 0,00723 L/mol
- Fase in condizioni STP
- Solido Confronta Fase in condizioni STP di tutti gli elementi →
- Punto di fusione
- 1906,85 °C Confronta Punto di fusione di tutti gli elementi →
- Punto di ebollizione
- 2670,85 °C Confronta Punto di ebollizione di tutti gli elementi →
- Conducibilità termica
- 93,9 W/(m·K) Confronta Conducibilità termica di tutti gli elementi →
- Capacità termica specifica
- 0,449 J/(g·K) Confronta Capacità termica specifica di tutti gli elementi →
- Capacità termica molare
- 23,35 J/(mol·K) Confronta Capacità termica molare di tutti gli elementi →
- Struttura cristallina
- Cubica a corpo centrato Confronta Struttura cristallina di tutti gli elementi →
Chimiche
- Elettronegatività (Pauling)
- 1,66 Confronta Elettronegatività (Pauling) di tutti gli elementi →
- Elettronegatività (Allen)
- 1,65
- Affinità elettronica
- 0,675 eV
- Energia di ionizzazione (1ª)
- 6,76651 eV Confronta Energia di ionizzazione (1ª) di tutti gli elementi →
- Energia di ionizzazione (2ª)
- 16,486362 eV Confronta Energia di ionizzazione (2ª) di tutti gli elementi →
- Energia di ionizzazione (3ª)
- 30,959107 eV Confronta Energia di ionizzazione (3ª) di tutti gli elementi →
- Energia di ionizzazione (4ª)
- 49,160169 eV Confronta Energia di ionizzazione (4ª) di tutti gli elementi →
- Energia di ionizzazione (5ª)
- 69,460239 eV Confronta Energia di ionizzazione (5ª) di tutti gli elementi →
- Stati di ossidazione
- −4, −2, −1, 0, +1, +2, +3, +4, +5, +6 Confronta Stati di ossidazione di tutti gli elementi →
- Elettroni di valenza
- 6 Confronta Elettroni di valenza di tutti gli elementi →
- Configurazione elettronica
- [Ar] 3d5 4s1
Termodinamiche
- Calore di fusione
- 0,21246826 eV Confronta Calore di fusione di tutti gli elementi →
- Calore di vaporizzazione
- 3,518682 eV Confronta Calore di vaporizzazione di tutti gli elementi →
- Calore di sublimazione
- 4,119811 eV
- Calore di atomizzazione
- 4,119811 eV
- Entalpia di atomizzazione
- 4,119604 eV
Nucleari
- Protoni
- 24 Confronta Protoni di tutti gli elementi →
- Neutroni
- 28 Confronta Neutroni di tutti gli elementi →
- Isotopi noti
- 30 Confronta Isotopi noti di tutti gli elementi →
- Isotopi stabili
- 3 Confronta Isotopi stabili di tutti gli elementi →
- Isotopo più stabile
- Cr-52
- Anno della scoperta
- 1797
Abbondanza
- Abbondanza (crosta terrestre)
- 102 mg/kg Confronta Abbondanza (crosta terrestre) di tutti gli elementi →
- Abbondanza (oceano)
- 3 × 10−4 mg/L Confronta Abbondanza (oceano) di tutti gli elementi →
Struttura cristallina
- Costante reticolare a
- 288 pm
Struttura elettronica
- Elettroni per guscio
- 2, 8, 13, 1 Confronta Elettroni per guscio di tutti gli elementi →
Identificativi
- Numero CAS
- 7440-47-3 Confronta Numero CAS di tutti gli elementi →
- Simbolo di termine
- 7S3
- InChI
- InChI=1S/Cr
- Chiave InChI
- VYZAMTAEIAYCRO-UHFFFAOYSA-N
Configurazione elettronica Misurato
Cr: 3d⁵ 4s¹[Ar] 3d⁵ 4s¹1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁵ 4s¹Modello atomico
Gli isotopi modificano il numero di neutroni, la massa e la stabilità — non la configurazione elettronica di un atomo neutro.
Modello atomico schematico, non in scala.
Impronta atomica
Spettro di emissione / assorbimento
Distribuzione isotopica
| Numero di massa | Massa atomica (u) | Abbondanza naturale | Emivita |
|---|---|---|---|
| 52 Stabile | 51,94050623 ± 0,00000063 | 83,7890% | Stabile |
| 53 Stabile | 52,94064815 ± 0,00000062 | 9,5010% | Stabile |
| 54 Stabile | 53,93887916 ± 0,00000061 | 2,3650% | Stabile |
Fase / Stato
Motivo: 1881,8 °C sotto il punto di fusione (1906,85 °C)
Schema non in scala
Punti di transizione di fase
Energie di transizione
Energia necessaria per fondere 1 mol al punto di fusione
Energia necessaria per vaporizzare 1 mol al punto di ebollizione
Energia necessaria per sublimare 1 mol al punto di sublimazione
Densità
In condizioni standard
In condizioni standard
Spettri atomici
Sono visualizzati 10 di 24. Ordinamento per carica ionica crescente.
Righe disponibili ?
| Ione | Carica | Righe totali | Probabilità di transizione | Designazioni dei livelli |
|---|---|---|---|---|
| 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 |
Livelli disponibili ?
| Ione | Carica | Livelli |
|---|---|---|
| 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 |
Raggi ionici
| Carica | Coordinazione | Spin | Raggio |
|---|---|---|---|
| +2 | 6 | low | 73 pm |
| +2 | 6 | high | 80 pm |
| +3 | 6 | N/D | 61.5 pm |
| +4 | 4 | N/D | 41 pm |
| +4 | 6 | N/D | 55.00000000000001 pm |
| +5 | 4 | N/D | 34.5 pm |
| +5 | 6 | N/D | 49 pm |
| +5 | 8 | N/D | 56.99999999999999 pm |
| +6 | 4 | N/D | 26 pm |
| +6 | 6 | N/D | 44 pm |
Composti
Isotopi (3)
| Numero di massa | Massa atomica (u) | Abbondanza naturale | Emivita | Modalità di decadimento | |
|---|---|---|---|---|---|
| 52 Stabile | 51,94050623 ± 0,00000063 | 83,7890% ± 0,0180% | Stabile | stable | |
| 53 Stabile | 52,94064815 ± 0,00000062 | 9,5010% ± 0,0170% | Stabile | stable | |
| 54 Stabile | 53,93887916 ± 0,00000061 | 2,3650% ± 0,0070% | Stabile | stable |
Righe spettrali
Sono visualizzati 50 di 2531. Per impostazione predefinita sono mostrate soltanto le righe spettrali con intensità misurata.
| Lunghezza d'onda (nm) | Intensità | Stadio di ionizzazione | Tipo | Transizione | Accuratezza | Fonte | |
|---|---|---|---|---|---|---|---|
| 540.978408 nm | 8500 | Cr I | emission | 3d4.4s2 a 5D → 3d5.(6S).4p z 5P* | Misurata | NIST | |
| 534.57965 nm | 5100 | Cr I | emission | 3d4.4s2 a 5D → 3d5.(6S).4p z 5P* | Misurata | NIST | |
| 529.827202 nm | 3540 | Cr I | emission | 3d4.4s2 a 5D → 3d5.(6S).4p z 5P* | Misurata | NIST | |
| 435.17622 nm | 3500 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5F* | Misurata | NIST | |
| 534.83147 nm | 3200 | Cr I | emission | 3d4.4s2 a 5D → 3d5.(6S).4p z 5P* | Misurata | NIST | |
| 434.450128 nm | 3100 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5F* | Misurata | NIST | |
| 433.944609 nm | 2600 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5F* | Misurata | NIST | |
| 526.415341 nm | 2600 | Cr I | emission | 3d4.4s2 a 5D → 3d5.(6S).4p z 5P* | Misurata | NIST | |
| 464.616212 nm | 2400 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) y 5P* | Misurata | NIST | |
| 529.669109 nm | 2100 | Cr I | emission | 3d4.4s2 a 5D → 3d5.(6S).4p z 5P* | Misurata | NIST | |
| 391.915844 nm | 2030 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5D* | Misurata | NIST | |
| 433.755701 nm | 1900 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5F* | Misurata | NIST | |
| 740.01798 nm | 1900 | Cr I | emission | 3d5.(6S).4p z 7P* → 3d5.(6S).5s e 7S | Misurata | NIST | |
| 465.215743 nm | 1750 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) y 5P* | Misurata | NIST | |
| 435.962444 nm | 1420 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5F* | Misurata | NIST | |
| 437.127465 nm | 1400 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5F* | Misurata | NIST | |
| 735.58903 nm | 1400 | Cr I | emission | 3d5.(6S).4p z 7P* → 3d5.(6S).5s e 7S | Misurata | NIST | |
| 461.612404 nm | 1360 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) y 5P* | Misurata | NIST | |
| 390.875593 nm | 1310 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5D* | Misurata | NIST | |
| 449.685195 nm | 1300 | Cr I | emission | 3d5.(6S).4s a 5S → 3d4.(5D).4s.4p.(3P*) y 5P* | Misurata | NIST | |
| 524.756509 nm | 1250 | Cr I | emission | 3d4.4s2 a 5D → 3d5.(6S).4p z 5P* | Misurata | NIST | |
| 460.074835 nm | 1190 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) y 5P* | Misurata | NIST | |
| 433.971051 nm | 1120 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5F* | Misurata | NIST | |
| 462.617342 nm | 1100 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) y 5P* | Misurata | NIST | |
| 435.104951 nm | 1080 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5F* | Misurata | NIST | |
| 438.4975 nm | 1060 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5F* | Misurata | NIST | |
| 526.571497 nm | 1050 | Cr I | emission | 3d4.4s2 a 5D → 3d5.(6S).4p z 5P* | Misurata | NIST | |
| 452.64538 nm | 960 | Cr I | emission | 3d5.(4G).4s a 5G → 3d5.(4G).4p z 5G* | Misurata | NIST | |
| 454.595302 nm | 930 | Cr I | emission | 3d5.(6S).4s a 5S → 3d4.(5D).4s.4p.(3P*) y 5P* | Misurata | NIST | |
| 532.832346 nm | 930 | Cr I | emission | 3d5.(6S).4p z 7P* → 3d5.(6S).4d e 7D | Misurata | NIST | |
| 388.32867 nm | 910 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5D* | Misurata | NIST | |
| 392.86372 nm | 880 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5D* | Misurata | NIST | |
| 388.521354 nm | 810 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5D* | Misurata | NIST | |
| 746.23079 nm | 800 | Cr I | emission | 3d5.(6S).4p z 7P* → 3d5.(6S).5s e 7S | Misurata | NIST | |
| 453.073802 nm | 770 | Cr I | emission | 3d5.(4G).4s a 5G → 3d5.(4G).4p z 5G* | Misurata | NIST | |
| 388.679508 nm | 740 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5D* | Misurata | NIST | |
| 392.102067 nm | 740 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5D* | Misurata | NIST | |
| 394.148757 nm | 720 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5D* | Misurata | NIST | |
| 697.83983 nm | 640 | Cr I | emission | 3d4.(5D).4s.4p.(3P*) y 7P* → 3d5.(6S).4d e 7D | Misurata | NIST | |
| 396.3684 nm | 620 | Cr I | emission | 3d5.(4G).4s a 5G → 3d5.(4G).4p y 5H* | Misurata | NIST | |
| 453.569676 nm | 600 | Cr I | emission | 3d5.(4G).4s a 5G → 3d5.(4G).4p z 5G* | Misurata | NIST | |
| 390.290908 nm | 590 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) z 5D* | Misurata | NIST | |
| 455.864413 nm | 590 | Cr II | emission | 3d5 b 4F → 3d4.(5D).4p z 4D* | Misurata | NIST | |
| 461.335727 nm | 590 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) y 5P* | Misurata | NIST | |
| 396.974253 nm | 570 | Cr I | emission | 3d5.(4G).4s a 5G → 3d5.(4G).4p y 5H* | Misurata | NIST | |
| 458.004789 nm | 560 | Cr I | emission | 3d5.(6S).4s a 5S → 3d4.(5D).4s.4p.(3P*) y 5P* | Misurata | NIST | |
| 530.074563 nm | 530 | Cr I | emission | 3d4.4s2 a 5D → 3d5.(6S).4p z 5P* | Misurata | NIST | |
| 397.665859 nm | 520 | Cr I | emission | 3d5.(4G).4s a 5G → 3d5.(4G).4p y 5H* | Misurata | NIST | |
| 454.04987 nm | 500 | Cr I | emission | 3d5.(4G).4s a 5G → 3d5.(4G).4p z 5G* | Misurata | NIST | |
| 459.139098 nm | 490 | Cr I | emission | 3d4.4s2 a 5D → 3d4.(5D).4s.4p.(3P*) y 5P* | Misurata | NIST |
Proprietà estese
Raggi covalenti (dati estesi)
- Raggio covalente (Pyykkö)
- 122 pm
- Raggio covalente (Pyykkö, legame doppio)
- 111 pm
- Raggio covalente (Pyykkö, legame triplo)
- 103 pm
- Raggio covalente (Bragg)
- 140 pm
Raggi di van der Waals
- Batsanov
- 205 pm
- Alvarez
- 245 pm
- UFF
- 302,3 pm
- MM3
- 225 pm
Raggi atomici e metallici
- Raggio atomico (Rahm)
- 233 pm
- Raggio metallico (C12)
- 128 pm
Scale di numerazione
- Mendeleev
- 51
- Pettifor
- 57
- Glawe
- 55
Scale di elettronegatività
- Ghosh
- 0
- Miedema
- 5
- Gunnarsson–Lundqvist
- 4
- Robles–Bartolotti
- 2
Polarizzabilità e dispersione
- Polarizzabilità dipolare
- 83 a.u.
- Polarizzabilità dipolare (inc.)
- 12 a.u.
- C₆
- 602 Ha·Bohr6
- C₆ (Gould–Bučko)
- 709 Ha·Bohr6
Affinità chimica
- Affinità protonica
- 791,3 kJ/mol
- Basicità in fase gassosa
- 768,4 kJ/mol
Parametri di Miedema
- Volume molare di Miedema
- 7,23 cm3/mol
- Densità elettronica di Miedema
- 5
Rischio di approvvigionamento ed economia
- Concentrazione della produzione
- 37
- Rischio relativo di approvvigionamento
- 6
- Distribuzione delle riserve
- 46
- Stabilità politica (principale produttore)
- 44
- Stabilità politica (principale detentore di riserve)
- 62
Transizioni di fase e allotropi
| Punto di fusione | 2180,15 K |
| Punto di ebollizione | 2944,15 K |
Categorie degli stati di ossidazione
Dati di riferimento avanzati
Costanti di schermaggio (7)
| n | Orbitale | 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 |
Dettaglio dei raggi cristallini (10)
| Carica | CN | Spin | rcrystal (pm) | Origine |
|---|---|---|---|---|
| 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, |
Modalità di decadimento degli isotopi (52)
| Isotopo | Modalità | Intensità |
|---|---|---|
| 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% |
Fattori di diffusione dei raggi X (751)
| Energia (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 |
Dati aggiuntivi
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
1.02×102 milligrams per kilogram
Riferimenti (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
Riferimenti (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.
Riferimenti (1)
- [6] Chromium https://periodic.lanl.gov/24.shtml
Riferimenti
(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.