Radium (Ra)
alkaline-earth-metalSolid
Peso atomico standard
[226]Configurazione elettronica
[Rn] 7s2Punto di fusione
699,85 °CPunto di ebollizione
1139,85 °CDensità
5000 kg/m³Stati di ossidazione
+2Elettronegatività (Pauling)
0,9Energia di ionizzazione (1ª)
5,278424 eVAnno della scoperta
1898Raggio atomico
215 pmDettagli
Radium is a heavy alkaline earth metal and the element below barium in group 2. All of its isotopes are radioactive; ²²⁶Ra, with a half-life of about 1600 years, is the best known and occurs in uranium ores as part of the ²³⁸U decay series. Its chemistry is dominated by the Ra²⁺ ion, which resembles Ba²⁺ but is less commonly handled because intense radioactivity limits direct study.
Radium is obtained commercially as bromide and chloride; it is doubtful if any appreciable stock of the isolated element now exists. The pure metal is brilliant white when freshly prepared, but blackens on exposure to air, probably due to formation of the nitride. It exhibits luminescence, as do its slats; it decomposes in water and is somewhat more volatile than barium. It is a member of the alkaline-earth group of metals. Radium imparts a carmine red color to a flame. Radium emits alpha, beta, and gamma rays and when mixed with beryllium produce neutrons. One gram of 226Ra undergoes 3.7 x 1010 disintegrations per second. The curie is defined as that amount of radioactivity which has the same disintegration rate as 1 g of 226Ra. Twenty five isotopes are now known; radium 226, the common isotope, has a half-life of 1600 years.
Radium was discovered by Marie Sklodowska Curie, a Polish chemist, and Pierre Curie, a French chemist, in 1898. Marie Curie obtained radium from pitchblende, a material that contains uranium, after noticing that unrefined pitchblende was more radioactive than the uranium that was separated from it. She reasoned that pitchblende must contain at least one other radioactive element. Curie needed to refine several tons of pitchblende in order to obtain tiny amounts of radium and polonium, another radioactive element discovered by Curie. One ton of uranium ore contains only about 0.14 grams of radium. Today, radium can be obtained as a byproduct of refining uranium and is usually sold as radium chloride (RaCl2) or radium bromide (RaBr2) and not as a pure material. Radium's most stable isotope, radium-226, has a half-life of about 1600 years. It decays into radon-222 through alpha decay or into lead-212 by ejecting a carbon-14 nucleus.
Radium was discovered in 1898 by Madame Curie in the pitchblende or uraninite of North Bohemia, where it occurs. There is about 1 g of radium in 7 tons of pitchblende. The element was isolated in 1911 by Mme. Curie and Debierne by the electrolysis of a solution of pure radium chloride employing a mercury cathode; on distillation in an atmosphere of hydrogen, this amalgam yielded the pure metal.
Freshly prepared radium metal has been reported as silvery white, but it rapidly darkens in air, probably through formation of nitride and oxide surface films. Macroscopic samples are extremely rare, and many physical details are less well established than for stable alkaline earth metals.
Radium once had major uses in self-luminous paints, radiation sources, and early cancer radiotherapy, chiefly because ²²⁶Ra and its decay products emit penetrating radiation. These applications have largely been abandoned or replaced by safer, more controllable radionuclides and non-radioactive phosphor systems. Today radium is used only in limited scientific, calibration, and historical-material contexts; some isotopes, especially ²²³Ra in specific radiopharmaceutical preparations, have specialized medical use as radioactive nuclides rather than as elemental metal.
The Curie, a unit used to describe the activity of a radioactive substance, is based on radium-226. It is equal to the number of atoms in a one gram sample of radium-226 that will decay in one second, or 37,000,000,000 decays per second.
Radium had been used to make self-luminous paints for watches, aircraft instrument dials and other instrumentation, but has largely been replaced by cobalt-60, a less dangerous radioactive source. A mixture of radium and beryllium will emit neutrons and is used as a neutron source. Radium is used to produce radon, a radioactive gas used to treat some types of cancer. A single gram of radium-226 will produce 0.000l milliliters of radon a day.
Radium is about one million times more active than uranium. The lab notebooks used by the Curies are too highly contaminated to be safely handled today.
One gram of radium produces about 0.0001 ml (stp) of emanation, or radon gas, per day. This is purged from the radium and sealed in minute tubes, which are used in the treatment of cancer and other diseases. Radium was used in the producing of self-luminous paints, neutron sources, and in medicine for the treatment of disease. Other radioisotopes, such as 60Co, are now being used in place of radium. Some of these sources are much more powerful, and others are safer to use. Radium loses about 1% of its activity in 25 years, being transformed into elements of lower atomic weight. Lead is a final product of disintegration. Stored radium and radium-containing products or minerals should be ventilated to prevent build-up of radon.
Isotopes in Earth/Planetary Science
The radioactive isotopes 223Ra (with a half-life of 275 h), 224Ra (with a half-life of 88 h), 226Ra (with a half-life of 1600 years), and 228Ra (with a half-life of 5.75 years) are used as tracers to determine water flow rates. They are ideal environmental tracers because they behave conservatively once released into a water mass (meaning only mixing and decay processes affect their distribution) [578] United States Geological Survey. Resources on Isotopes-Periodic Table-Radium, U.S. Geological Survey (2014), Feb. 25; http://wwwrcamnl.wr.usgs.gov/isoig/period/ra_iig.html.. The activity ratios A(224Ra)/A(223Ra), A(223Ra)/A(226Ra), A(224Ra)/A(228Ra), and A(228Ra)/A(226Ra) have been used in lake studies to monitor and detect water inflow and mixing, to determine sources of inflowing water, and to monitor introduced water masses as they move within a body of water (i.e. a lake) [578] United States Geological Survey. Resources on Isotopes-Periodic Table-Radium, U.S. Geological Survey (2014), Feb. 25; http://wwwrcamnl.wr.usgs.gov/isoig/period/ra_iig.html., [579] T. F. Kraemer. Limnol. Oceanogr.50, 158 (2005).. For example, submarine groundwater discharge is an important pathway that transports dissolved substances from aquifers below a seabed to the coastal ocean. Submarine groundwater discharge can be difficult to quantify because it is both spatially and temporally variable. As a result, its relative importance in coastal ocean chemical budgets is commonly poorly known. Peterson et al. [572] R. N. Peterson, W. C. Burnett, M. Taniguchi, J. Chen, I. R. Santos, T. Ishitobi. J. Geophys. Res.113, C09021 (2008). used an hourly time series of measurements of multiple radium isotopes 223Ra, 224Ra, and 226Ra to quantify submarine groundwater discharge. They also used 222Rn (with a half-life of 3.8 days) measurements to independently quantify submarine groundwater discharge.
Isotopes in Geochronology
226Ra and 228Ra can be used for dating materials up to a few thousand years in age because the half-lives of 226Ra and 228Ra are 1600 years and 5.75 years, respectively, even though the long-lived 226Ra is found in nature as a result of its continuous production by the decay of 238U. For example, long-lived 226Ra has been used to date a limestone cave in central Switzerland, corals in the Indian Ocean, and Pleistocene gravel terraces [580] J. Eikenberg. “Radium isotope systematics in nature: applications in geochronology and hydrogeochemistry”, in Habilitation Thesis, Earth Science Department.. The activity ratio A(224Ra)/A(223Ra) is a potential age calculator for old lake water because the low 223Ra and 224Ra activities in old lake water are relatively unaffected by mixing [579] T. F. Kraemer. Limnol. Oceanogr.50, 158 (2005)..
Isotopes in Medicine
226Ra is used in brachytherapy (Fig. IUPAC.88.1), which is a method of localized treatment of various types of cancer. A sealed implant (such as a rod, seed, or needle) containing the radioactive isotope 226Ra is inserted into or near a patient’s tumor to apply a high dose of radiation to the tumor. The sealed implant is inserted by a physician or by an automated device (called a remote afterloader), and it is removed from the patient once the tumor is destroyed [75] J. Peterson, M. McDonell, L. Haroun, F. Monette, R. D. Hildebrand, A. Taboas. Radiological and Chemical Fact Sheets to Support Health Risk Analyses for Contaminated Areas, Prepared by Argonne National Laboratory Environmental Science Division in collaboration with U.S. Department of Energy, Richland Operations Office and Chicago Operations Office (2014), Feb. 22; http://www.remm.nlm.gov/ANL_ContaminantFactSheets_All_070418.pdf., [581] United States Nuclear Regulatory Commission (U.S. NRC). Frequently Asked Questions (FAQs) Regarding Radium-226 Overview, United States Nuclear Regulatory Commission (U.S. NRC) (2017), April 8; https://scp.nrc.gov/narmtoolbox/radium%20faq102008.pdf..
Radium chemistry is almost entirely divalent. Representative salts include radium chloride (RaCl₂), radium bromide (RaBr₂), radium sulfate (RaSO₄), and radium carbonate (RaCO₃). The sulfate is very sparingly soluble, resembling barium sulfate (BaSO₄), and this behavior is important in separations and environmental immobilization. Radium forms ionic compounds rather than strongly covalent species, and detailed structural data are limited by radioactivity and scarcity.
See more information at the Radium compound page.
Radium is highly radiotoxic. Ingested or inhaled Ra²⁺ can follow calcium pathways and deposit in bone, where alpha-emitting decay products deliver damaging local doses. ²²⁶Ra also produces radioactive radon (²²²Rn), creating an inhalation hazard in enclosed spaces. External gamma radiation, contamination spread, and long-lived residues make radium sources difficult to handle safely.
Inhalation, injection, or body exposure to radium can cause cancer and other body disorders. The maximum permissible border in the total body for 226Ra is 7400 becquerel.
Natural radium is produced continuously by decay of uranium and thorium isotopes in rocks and soils. It can enter groundwater, especially where reducing chemistry, salinity, or mineral dissolution mobilizes alkaline earth ions. Radium may co-precipitate with barite and other sulfate or carbonate minerals, limiting transport in some settings. Its environmental significance comes from radioactivity rather than chemical abundance.
Radium has no ordinary commodity market. It was historically isolated from uranium ores, notably pitchblende residues, by laborious chemical separations, but routine industrial demand disappeared as its hazards became clear and alternatives became available. Present supplies are small, controlled, and usually associated with legacy sources, regulatory management, or isotope-specific production and purification. Disposal, security, and contamination control are often more economically important than acquisition of new radium metal or salts.
Originally, radium was obtained from the rich pitchblende ore found in Joachimsthal, Bohemia. The carnotite sands of Colorado furnish some radium, but richer ores are found in the Republic of Zaire and the Great Lake region of Canada. Radium is present in all uranium minerals, and could be extracted, if desired, from the extensive wastes of uranium processing. Large uranium deposits are located in Ontario, New Mexico, Utah, Australia, and elsewhere.
Radium is not a primordial stable element. Its isotopes are generated in decay chains of heavier nuclides, mainly uranium and thorium, whose ultimate origins are rapid neutron-capture nucleosynthesis before incorporation into the Solar System. Because radium isotopes are short-lived on geological and cosmic timescales, any detectable natural radium indicates continuing production from longer-lived parents.
- Radium was named from the Latin word for ray because of its intense radioactivity.
- Pure radium compounds can self-warm from radioactive decay energy.
- Radium luminous paints used zinc sulfide phosphors, not glowing radium metal.
- The isotope ²²⁸Ra belongs to the ²³²Th decay series.
- Radium and barium are chemically similar enough to make separation difficult.
Immagini
Proprietà
Fisiche
- Raggio atomico (empirico)
- 215 pm Confronta Raggio atomico (empirico) di tutti gli elementi →
- Raggio covalente
- 221 pm Confronta Raggio covalente di tutti gli elementi →
- Raggio di van der Waals
- 283 pm Confronta Raggio di van der Waals di tutti gli elementi →
- Densità
- 5000 kg/m³ Confronta Densità di tutti gli elementi →
- Volume molare
- 0,045 L/mol
- Fase in condizioni STP
- Solido Confronta Fase in condizioni STP di tutti gli elementi →
- Punto di fusione
- 699,85 °C Confronta Punto di fusione di tutti gli elementi →
- Punto di ebollizione
- 1139,85 °C Confronta Punto di ebollizione di tutti gli elementi →
Chimiche
- Elettronegatività (Pauling)
- 0,9 Confronta Elettronegatività (Pauling) di tutti gli elementi →
- Elettronegatività (Allen)
- 0,89
- Affinità elettronica
- 0,096 eV
- Energia di ionizzazione (1ª)
- 5,278424 eV Confronta Energia di ionizzazione (1ª) di tutti gli elementi →
- Energia di ionizzazione (2ª)
- 10,147215 eV Confronta Energia di ionizzazione (2ª) di tutti gli elementi →
- Energia di ionizzazione (3ª)
- 31,000107 eV Confronta Energia di ionizzazione (3ª) di tutti gli elementi →
- Energia di ionizzazione (4ª)
- 41,000141 eV Confronta Energia di ionizzazione (4ª) di tutti gli elementi →
- Energia di ionizzazione (5ª)
- 52,900182 eV Confronta Energia di ionizzazione (5ª) di tutti gli elementi →
- Stati di ossidazione
- +2 Confronta Stati di ossidazione di tutti gli elementi →
- Elettroni di valenza
- 2 Confronta Elettroni di valenza di tutti gli elementi →
- Configurazione elettronica
- [Rn] 7s2
Termodinamiche
- Calore di fusione
- 0,08291444 eV Confronta Calore di fusione di tutti gli elementi →
- Calore di vaporizzazione
- 1,171167 eV Confronta Calore di vaporizzazione di tutti gli elementi →
- Calore di sublimazione
- 1,647925 eV
- Calore di atomizzazione
- 1,647925 eV
- Entalpia di atomizzazione
- 1,647925 eV
Nucleari
- Protoni
- 88 Confronta Protoni di tutti gli elementi →
- Neutroni
- 138 Confronta Neutroni di tutti gli elementi →
- Isotopi noti
- 35 Confronta Isotopi noti di tutti gli elementi →
- Isotopi stabili
- 0 Confronta Isotopi stabili di tutti gli elementi →
- Numero di massa (isotopo più stabile)
- 226
- Isotopo più stabile
- Ra-226
- Anno della scoperta
- 1898
Abbondanza
- Abbondanza (crosta terrestre)
- 9e-7 mg/kg Confronta Abbondanza (crosta terrestre) di tutti gli elementi →
- Abbondanza (oceano)
- 8,9 × 10−11 mg/L Confronta Abbondanza (oceano) di tutti gli elementi →
Struttura cristallina
N/D
Struttura elettronica
- Elettroni per guscio
- 2, 8, 18, 32, 18, 8, 2 Confronta Elettroni per guscio di tutti gli elementi →
Identificativi
- Numero CAS
- 7440-14-4 Confronta Numero CAS di tutti gli elementi →
- Simbolo di termine
- 1S0
- InChI
- InChI=1S/Ra
- Chiave InChI
- HCWPIIXVSYCSAN-UHFFFAOYSA-N
Configurazione elettronica Misurato
Ra: 7s²[Rn] 7s²1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d¹⁰ 6s² 6p⁶ 7s²Modello 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
Nessun isotopo stabile.
| Numero di massa | Massa atomica (u) | Abbondanza naturale | Emivita |
|---|---|---|---|
| 206 Radioattivo | 206,003828 ± 0,000019 | N/D | 240 ms |
| 205 Radioattivo | 205,006268 ± 0,000076 | N/D | 220 ms |
| 216 Radioattivo | 216,0035334 ± 0,0000094 | N/D | 172 ns |
| 231 Radioattivo | 231,041027 ± 0,000012 | N/D | 104 secondi |
| 230 Radioattivo | 230,037055 ± 0,000011 | N/D | 93 minuti |
Fase / Stato
Motivo: 674,9 °C sotto il punto di fusione (699,85 °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 88. Ordinamento per carica ionica crescente.
Righe disponibili ?
| Ione | Carica | Righe totali | Probabilità di transizione | Designazioni dei livelli |
|---|---|---|---|---|
| Ra I | 0 | 143 | 19 | 112 |
| Ra II | +1 | 63 | 9 | 63 |
Livelli disponibili ?
| Ione | Carica | Livelli |
|---|---|---|
| Ra I | 0 | 82 |
| Ra II | +1 | 37 |
| Ra III | +2 | 2 |
| Ra IV | +3 | 2 |
| Ra V | +4 | 2 |
| Ra VI | +5 | 2 |
| Ra VII | +6 | 2 |
| Ra VIII | +7 | 2 |
| Ra IX | +8 | 2 |
| Ra X | +9 | 2 |
Dati sulla struttura cristallina non disponibili
Raggi ionici
| Carica | Coordinazione | Spin | Raggio |
|---|---|---|---|
| +2 | 8 | N/D | 148 pm |
| +2 | 12 | N/D | 170 pm |
Composti
Isotopi (5)
| Numero di massa | Massa atomica (u) | Abbondanza naturale | Emivita | Modalità di decadimento | |
|---|---|---|---|---|---|
| 206 Radioattivo | 206,003828 ± 0,000019 | N/D | 240 ms | α ≈100%β+ ? | |
| 205 Radioattivo | 205,006268 ± 0,000076 | N/D | 220 ms | α ≈100%β+ ? | |
| 216 Radioattivo | 216,0035334 ± 0,0000094 | N/D | 172 ns | α =100%ε<1e-8% | |
| 231 Radioattivo | 231,041027 ± 0,000012 | N/D | 104 secondi | β- =100% | |
| 230 Radioattivo | 230,037055 ± 0,000011 | N/D | 93 minuti | β- =100% |
Righe spettrali
Sono visualizzati 50 di 90. Per impostazione predefinita sono mostrate soltanto le righe spettrali con intensità misurata.
| Lunghezza d'onda (nm) | Intensità | Stadio di ionizzazione | Tipo | Transizione | Accuratezza | Fonte | |
|---|---|---|---|---|---|---|---|
| 381.44219 nm | 200 | Ra II | emission | 7s 2S → 7p 2P* | Misurata | NIST | |
| 468.22394 nm | 100 | Ra II | emission | 7s 2S → 7p 2P* | Misurata | NIST | |
| 482.59281 nm | 100 | Ra I | emission | 7s2 1S → 7s.7p 1P* | Misurata | NIST | |
| 566.0812 nm | 50 | Ra I | emission | 7s.6d 3D → 6d.7p 3F* | Misurata | NIST | |
| 714.12167 nm | 50 | Ra I | emission | 7s2 1S → 7s.7p 3P* | Misurata | NIST | |
| 453.3111 nm | 30 | Ra II | emission | 7p 2P* → 8s 2S | Misurata | NIST | |
| 620.0304 nm | 30 | Ra I | emission | 7s.6d 3D → 6d.7p 3F* | Misurata | NIST | |
| 443.6259 nm | 20 | Ra II | emission | 7p 2P* → 7d 2D | Misurata | NIST | |
| 540.0231 nm | 20 | Ra I | emission | 7s.6d 3D → 6d.7p 3D* | Misurata | NIST | |
| 540.6796 nm | 20 | Ra I | emission | 7s.6d 3D → 6d.7p 3D* | Misurata | NIST | |
| 555.5852 nm | 20 | Ra I | emission | 7s.7p 3P* → 7s.7d 3D | Misurata | NIST | |
| 581.3628 nm | 20 | Ra II | emission | 7p 2P* → 8s 2S | Misurata | NIST | |
| 644.62 nm | 20 | Ra I | emission | 7s.7p 3P* → 7s.7d 3D | Misurata | NIST | |
| 648.7319 nm | 20 | Ra I | emission | 7s.6d 3D → 6d.7p 3F* | Misurata | NIST | |
| 698.0232 nm | 20 | Ra I | emission | 7s.6d 3D → 6d.7p 3F* | Misurata | NIST | |
| 711.8486 nm | 20 | Ra I | emission | 7s.6d 3D → 6d.7p 3F* | Misurata | NIST | |
| 722.5166 nm | 20 | Ra I | emission | 7s.6d 1D → 6d.7p 1D* | Misurata | NIST | |
| 485.6071 nm | 10 | Ra I | emission | 7s.6d 3D → 7s.5f 3F* | Misurata | NIST | |
| 485.942 nm | 10 | Ra II | emission | 5f 2F* → 6g 2G | Misurata | NIST | |
| 492.752 nm | 10 | Ra II | emission | 5f 2F* → 6g 2G | Misurata | NIST | |
| 520.5948 nm | 10 | Ra I | emission | 7s.6d 3D → 6d.7p 3D* | Misurata | NIST | |
| 528.3277 nm | 10 | Ra I | emission | 7s.7p 3P* → 7s.7d 3D | Misurata | NIST | |
| 532.029 nm | 10 | Ra I | emission | 7s.6d 3D → 6d.7p 3D* | Misurata | NIST | |
| 539.9784 nm | 10 | Ra I | emission | 7s.6d 3D → 6d.7p 3D* | Misurata | NIST | |
| 550.1985 nm | 10 | Ra I | emission | 7s.7p 3P* → 7p2? 3P | Misurata | NIST | |
| 555.3574 nm | 10 | Ra I | emission | 7s.7p 3P* → 7s.7d 3D | Misurata | NIST | |
| 561.6661 nm | 10 | Ra I | emission | 7s.6d 3D → 6d.7p 3D* | Misurata | NIST | |
| 633.6899 nm | 10 | Ra I | emission | 7s.6d 1D → 7s.8p 1P* | Misurata | NIST | |
| 659.3341 nm | 10 | Ra II | emission | 5f 2F* → 5g 2G | Misurata | NIST | |
| 671.932 nm | 10 | Ra II | emission | 5f 2F* → 5g 2G | Misurata | NIST | |
| 731.0269 nm | 10 | Ra I | emission | 7s.7p 3P* → 7s.8s 3S | Misurata | NIST | |
| 419.4091 nm | 8 | Ra II | emission | 5f 2F* → 7g 2G | Misurata | NIST | |
| 424.472 nm | 8 | Ra II | emission | 5f 2F* → 7g 2G | Misurata | NIST | |
| 464.1284 nm | 8 | Ra I | emission | 7s.6d 3D → 7s.5f 3F* | Misurata | NIST | |
| 469.9272 nm | 8 | Ra I | emission | 7s.6d 3D → 7s.5f 3F* | Misurata | NIST | |
| 548.215 nm | 8 | Ra I | emission | 7s.6d 3D → 6d.7p 3D* | Misurata | NIST | |
| 508.1036 nm | 6 | Ra I | emission | 7s.6d 3D → 6d.7p 3P* | Misurata | NIST | |
| 566.165 nm | 6 | Ra II | emission | 8p 2P* → 9d 2D | Misurata | NIST | |
| 389.455 nm | 5 | Ra II | emission | 5f 2F* → 8g 2G | Misurata | NIST | |
| 497.179 nm | 5 | Ra I | emission | 7s.6d 3D → 6d.7p 3P* | Misurata | NIST | |
| 504.154 nm | 5 | Ra I | emission | 7s.6d 3D → 6d.7p 3P* | Misurata | NIST | |
| 560.143 nm | 5 | Ra I | emission | 7s.6d 3D → 7s.8p 3P* | Misurata | NIST | |
| 577.824 nm | 5 | Ra I | emission | 7s.6d 1D → 6d.7p 3P* | Misurata | NIST | |
| 579.5745 nm | 5 | Ra I | emission | 7s.7p 3P* → 7p2? 3P | Misurata | NIST | |
| 581.1588 nm | 5 | Ra I | emission | 7s.6d 3D → 6d.7p 1D* | Misurata | NIST | |
| 616.7051 nm | 5 | Ra I | emission | 7s.6d 3D → 6d.7p 1D* | Misurata | NIST | |
| 707.79042 nm | 5 | Ra II | emission | 6d 2D → 7p 2P* | Misurata | NIST | |
| 417.798 nm | 4 | Ra I | emission | 7s.6d 3D → 7s.6f 3F* | Misurata | NIST | |
| 430.5 nm | 4 | Ra I | emission | 7s.6d 3D → 7s.6f 3F* | Misurata | NIST | |
| 490.3263 nm | 4 | Ra I | emission | 7s.6d 3D → 6d.7p 3P* | Misurata | NIST |
Proprietà estese
Raggi covalenti (dati estesi)
- Raggio covalente (Pyykkö)
- 201 pm
- Raggio covalente (Pyykkö, legame doppio)
- 173 pm
- Raggio covalente (Pyykkö, legame triplo)
- 159 pm
Raggi di van der Waals
- Truhlar
- 283 pm
- UFF
- 367,7 pm
- MM3
- 327 pm
Raggi atomici e metallici
- Raggio atomico (Rahm)
- 292 pm
Scale di numerazione
- Mendeleev
- 10
- Pettifor
- 13
- Glawe
- 13
Scale di elettronegatività
- Ghosh
- 0
Polarizzabilità e dispersione
- Polarizzabilità dipolare
- 246 a.u.
- Polarizzabilità dipolare (inc.)
- 4 a.u.
Transizioni di fase e allotropi
| Punto di fusione | 969,15 K |
Categorie degli stati di ossidazione
Dati di riferimento avanzati
Dettaglio dei raggi cristallini (2)
| Carica | CN | Spin | rcrystal (pm) | Origine |
|---|---|---|---|---|
| 2 | VIII | 162 | from r^3 vs V plots, | |
| 2 | XII | 184 | from r^3 vs V plots, |
Modalità di decadimento degli isotopi (55)
| Isotopo | Modalità | Intensità |
|---|---|---|
| 201 | A | 100% |
| 202 | A | 100% |
| 203 | A | 100% |
| 203 | B+ | — |
| 204 | A | 100% |
| 204 | B+ | — |
| 205 | A | 100% |
| 205 | B+ | — |
| 206 | A | 100% |
| 206 | B+ | — |
Fattori di diffusione dei raggi X (516)
| Energia (eV) | f₁ | f₂ |
|---|---|---|
| 10 | — | 0,04162 |
| 10,1617 | — | 0,04479 |
| 10,3261 | — | 0,0482 |
| 10,4931 | — | 0,05188 |
| 10,6628 | — | 0,05584 |
| 10,8353 | — | 0,0601 |
| 11,0106 | — | 0,06468 |
| 11,1886 | — | 0,06961 |
| 11,3696 | — | 0,07492 |
| 11,5535 | — | 0,08102 |
Dati aggiuntivi
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
9×10-7 milligrams per kilogram
Riferimenti (1)
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
8.9×10-11 milligrams per liter
Riferimenti (1)
Sources
Sources of this element.
Originally, radium was obtained from the rich pitchblende ore found in Joachimsthal, Bohemia. The carnotite sands of Colorado furnish some radium, but richer ores are found in the Republic of Zaire and the Great Lake region of Canada. Radium is present in all uranium minerals, and could be extracted, if desired, from the extensive wastes of uranium processing. Large uranium deposits are located in Ontario, New Mexico, Utah, Australia, and elsewhere.
Riferimenti (1)
- [6] Radium https://periodic.lanl.gov/88.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 Radium.
The element property data was retrieved from publications.