Bohrium (Bh)
transition-metalSolid
Peso atómico estándar
[270]Configuración electrónica
[Rn] 7s2 5f14 6d5Punto de fusión
N/DPunto de ebullición
N/DDensidad
3,71e+4 kg/m³Estados de oxidación
+3, +4, +5, +7Electronegatividad (Pauling)
N/DEnergía de ionización (1.ª)
7,7 eVAño de descubrimiento
1976Radio atómico
128 pmDetalles
Bohrium is a synthetic transactinide element in group 7, below rhenium. It has no stable isotopes and has been made only atom by atom in heavy-ion nuclear reactions or as decay products of heavier superheavy nuclei. Its chemistry is known from a small number of rapid experiments and is consistent with a very heavy group 7 metal, with the +7 state especially important. No natural role or technological use is known.
Bohrium does not occur naturally in the Earth’s crust. Bohrium was first synthesized by German scientists at the GSI Center for Heavy Ion Research in Darmstadt, Germany in 1981 using the nuclear reaction 209Bi (54Cr, n) 262Bh. The element is named for Niels Bohr (Fig. IUPAC.107.1), the Nobel Prize winning physicist [649], [650]. Bohrium has no known isotopic applications aside from scientific research.
Bohrium is named after Niels Bohr.
First produced in 1976 by scientists working at the Joint Institute for Nuclear Research in Dubna, Russia, and later confirmed in 1981 by Peter Armbruster, Gottfried Münzenber and their team working at the Gesellschaft für Schwerionenforschung in Darmstadt, Germany, bohrium was produced by bombarding a target of bismuth-209 with ions of chromium-54. Bohrium's most stable isotope, bohrium-270, has a half-life of about 1 minute. It decays into dubnium-266 through alpha decay.
Formally known as Ns, Nielsbohrium
In 1976 Soviet scientists at Dubna announced they had synthesized element 107 by bombarding 204Bi with heavy nuclei of 54Cr. Reports say that experiments in 1975 had allowed scientists "to glimpse" the new element for 2/1000 s. A rapidly rotating cylinder, coated with a thin layer of bismuth metal, was used as a target. This was bombarded by a stream of 54Cr ions fired tangentially.
The existence of element 107 was confirmed by a team of West German physicists at the Heavy Ion Research Laboratory at Darmstadt, who created and identified six nuclei of element 107.
No macroscopic sample of bohrium has been prepared, so its visible appearance is unknown. It is expected from periodic trends and calculations to be a dense metallic solid under ordinary conditions, but this has not been directly observed.
Bohrium has no practical use outside scientific research. Its isotopes are used as subjects in nuclear-structure studies, decay-chain assignments, and tests of models for superheavy-element stability. Chemical experiments with individual atoms have also used bohrium to examine whether group trends continue into the 6d transition series. The element is not available for devices, materials, medicine, or industrial chemistry.
Since only a few atoms of bohrium have ever been made, there are currently no uses for bohrium outside of basic scientific research.
No weighable bohrium compound has been isolated. The best established chemical evidence concerns bohrium in the +7 oxidation state, especially a volatile oxychloride assigned as bohrium oxychloride, BhO₃Cl, formed and transported in gas-phase atom-at-a-time experiments. Its behavior resembles that of rhenium oxychloride, ReO₃Cl, supporting placement in group 7. Other oxidation states and compounds, including oxides and halides, are predicted by analogy and relativistic calculations but remain poorly characterized experimentally.
See more information at the Bohrium compound page.
Bohrium isotopes are radioactive and decay by alpha emission or spontaneous fission, depending on the isotope. Because only a few atoms are produced, chemical toxicity has not been measured and is not a practical exposure issue outside specialized laboratories. The main hazards in production experiments are ionizing radiation, activated targets and equipment, and decay products handled under accelerator radiological controls.
Bohrium has no known natural occurrence and no environmental cycle. Any atom released from an experiment would decay rapidly to other nuclides, so persistence, transport, and bioaccumulation of elemental bohrium have not been observed. Its environmental relevance is therefore limited to controlled research facilities and the management of radioactive activation products from those facilities.
Bohrium has no commodity market, commercial supply chain, or recoverable inventory. It is produced in accelerator experiments by fusing heavy target nuclei with ion beams, for example in reactions involving bismuth or actinide targets, or it appears in decay chains of heavier synthetic elements. Production yields are at the level of individual atoms, and separation is performed only for immediate detection or chemical study. Economic considerations are those of superheavy-element research infrastructure rather than material demand, substitution, or recycling.
Obtained by bombarding bismuth-204 with chromium-54.
Bohrium is not expected to survive as a primordial element because all known and predicted accessible isotopes are far too short-lived on geological or cosmic timescales. Superheavy nuclei near bohrium could be formed transiently in extreme neutron-rich nucleosynthesis, but no extraterrestrial bohrium has been detected. Claims about longer-lived superheavy nuclei remain theoretical for this element.
- Bohrium is named for Niels Bohr, with the spelling chosen to fit the usual element-name ending.
- The accepted symbol is Bh; the temporary systematic name was unniseptium.
- Unambiguous identification relies on correlated decay chains, not on collecting visible material.
- Atom-at-a-time chemistry showed bohrium behaves more like rhenium than like a chemically anomalous outlier.
- The first confirmed syntheses used cold-fusion heavy-ion reactions.
Imágenes
Propiedades
Físicas
- Radio atómico (empírico)
- 128 pm Comparar Radio atómico (empírico) de todos los elementos →
- Densidad
- 3,71 × 104 kg/m³ Comparar Densidad de todos los elementos →
Químicas
- Afinidad electrónica
- 0,44 eV
- Energía de ionización (1.ª)
- 7,7 eV Comparar Energía de ionización (1.ª) de todos los elementos →
- Energía de ionización (2.ª)
- 17,50006 eV Comparar Energía de ionización (2.ª) de todos los elementos →
- Energía de ionización (3.ª)
- 26,700092 eV Comparar Energía de ionización (3.ª) de todos los elementos →
- Energía de ionización (4.ª)
- 37,300128 eV Comparar Energía de ionización (4.ª) de todos los elementos →
- Energía de ionización (5.ª)
- 49,000169 eV Comparar Energía de ionización (5.ª) de todos los elementos →
- Estados de oxidación
- +3, +4, +5, +7 Comparar Estados de oxidación de todos los elementos →
- Electrones de valencia
- 7 Comparar Electrones de valencia de todos los elementos →
- Configuración electrónica
- [Rn] 7s2 5f14 6d5
Termodinámicas
N/D
Nucleares
- Protones
- 107 Comparar Protones de todos los elementos →
- Neutrones
- 163 Comparar Neutrones de todos los elementos →
- Isótopos conocidos
- 19 Comparar Isótopos conocidos de todos los elementos →
- Isótopos estables
- 0 Comparar Isótopos estables de todos los elementos →
- Número másico (isótopo más estable)
- 270
- Isótopo más estable
- Bh-270
- Año de descubrimiento
- 1976
Abundancia
N/D
Estructura cristalina
N/D
Estructura electrónica
- Electrones por capa
- 2, 8, 18, 32, 32, 13, 2 Comparar Electrones por capa de todos los elementos →
Identificadores
- Número CAS
- 54037-14-8 Comparar Número CAS de todos los elementos →
- Símbolo del término
- 5/2
- InChI
- InChI=1S/Bh
- Clave InChI
- INOXRQQPOOCQPH-UHFFFAOYSA-N
Configuración electrónica Predicho
Bh: 5f¹⁴ 6d⁵ 7s²[Rn] 5f¹⁴ 6d⁵ 7s²1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d¹⁰ 6s² 6p⁶ 5f¹⁴ 6d⁵ 7s²Modelo atómico
Los isótopos cambian el número de neutrones, la masa y la estabilidad, pero no la configuración electrónica de un átomo neutro.
Modelo atómico esquemático, no a escala.
Huella atómica
Espectro de emisión / absorción
Distribución isotópica
No hay isótopos estables.
| Número másico | Masa atómica (u) | Abundancia natural | Periodo de semidesintegración |
|---|---|---|---|
| 263 Radiactivo | 263,12292 ± 0,00033 | N/D | 200 ms |
| 268 Radiactivo | 268,12969 ± 0,00041 | N/D | 190 segundos |
| 262 Radiactivo | 262,12297 ± 0,00033 | N/D | 84 ms |
| 276 Radiactivo | 276,149169 ± 0,000644 | N/D | 60 segundos |
| 274 Radiactivo | 274,14355 ± 0,00065 | N/D | 57 segundos |
Fase / Estado
No hay datos disponibles sobre la fase o el estado
Espectros atómicos
Se muestran 10 de 96. Ordenado por carga del ion (ascendente).
Niveles disponibles ?
| Ion | Carga | Niveles |
|---|---|---|
| Bh I | 0 | 2 |
| Bh II | +1 | 2 |
| Bh III | +2 | 2 |
| Bh IV | +3 | 2 |
| Bh V | +4 | 2 |
| Bh VI | +5 | 2 |
| Bh VII | +6 | 2 |
| Bh VIII | +7 | 2 |
| Bh IX | +8 | 2 |
| Bh X | +9 | 2 |
No hay datos disponibles sobre la fase o el estado
Compuestos
Isótopos (5)
| Número másico | Masa atómica (u) | Abundancia natural | Periodo de semidesintegración | Modo de desintegración | |
|---|---|---|---|---|---|
| 263 Radiactivo | 263,12292 ± 0,00033 | N/D | 200 ms | α ? | |
| 268 Radiactivo | 268,12969 ± 0,00041 | N/D | 190 segundos | α ?SF ? | |
| 262 Radiactivo | 262,12297 ± 0,00033 | N/D | 84 ms | α ≈100%SF<20% | |
| 276 Radiactivo | 276,149169 ± 0,000644 | N/D | 60 segundos | α ?SF ? | |
| 274 Radiactivo | 274,14355 ± 0,00065 | N/D | 57 segundos | α =100% |
Propiedades ampliadas
Radios covalentes (ampliados)
- Radio covalente (Pyykkö)
- 141 pm
- Radio covalente (Pyykkö, enlace doble)
- 128 pm
- Radio covalente (Pyykkö, enlace triple)
- 119 pm
Escalas de numeración
- Mendeleev
- 58
Polarizabilidad y dispersión
- Polarizabilidad dipolar
- 38 a.u.
- Polarizabilidad dipolar (incert.)
- 4 a.u.
Categorías de estados de oxidación
Datos de referencia avanzados
Modos de desintegración de los isótopos (32)
| Isótopo | Modo | Intensidad |
|---|---|---|
| 260 | A | 100% |
| 260 | B+ | — |
| 260 | SF | — |
| 261 | A | 100% |
| 261 | SF | — |
| 262 | A | 100% |
| 262 | SF | 20% |
| 263 | A | — |
| 264 | A | 86% |
| 264 | SF | 14% |
Datos adicionales
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
Not Applicable
Referencias (1)
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
Not Applicable
Referencias (1)
Referencias
(8)
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 Bohrium.