Neptunium (Np)
actinideSolid
प्रमाणित अणुभार
[237]इलेक्ट्रॉन संरूपण
[Rn] 7s2 5f4 6d1द्रवणांक
643.85 °Cउत्कलनांक
3901.85 °Cघनता
2.025e+4 kg/m³ऑक्सिडीकरण अवस्था
+2, +3, +4, +5, +6, +7विद्युतऋणता (पॉलिंग)
1.36आयनीकरण ऊर्जा (पहिली)
6.265608 eVशोधाचे वर्ष
1940अणुत्रिज्या
175 pmतपशील
Neptunium is a radioactive actinide and the first transuranium element. It is produced mainly by neutron reactions involving uranium in nuclear reactors and occurs naturally only in minute amounts from neutron capture and decay processes in uranium ores. Its chemistry bridges uranium and plutonium, with several accessible oxidation states in solution. The isotope ²³⁷Np is the most important for handling and study because of its long half-life and availability as a reactor by-product.
Neptunium metal buttons (photo courtesy Lawrence Berkeley National Laboratory)
Neptunium was first produced by Edwin M. McMillian and Philip H. Abelson, working at the University of California, Berkeley, in 1940. They produced neptunium-239, an isotope of neptunium with a half-life of about 2.4 days, by bombarding uranium with slow moving neutrons.
Named for the planet Neptune (named after the Roman god of the sea), the next planet out from the Sun after Uranus. There were many early false reports of the discovery of neptunium. The most significant was by Enrico Fermi who believed that bombarding uranium with neutrons followed by beta decay would lead to the formation of element 93. In 1934, he bombarded uranium atoms with neutrons and reported that he had produced elements 93 and 94. As it turned out, Fermi had actually fissioned or split uranium atoms into many fragment radioisotopes. The explanation and announcement of the discovery of fission was later published by Hahn and Strassman, although it was their co-worker Lisa Meitner who had correctly interpreted the results of the experiments. In 1940, with excitement about fission reaching the University of California at Berkeley, Professor Edwin McMillan and graduate student Philip Abelson bombarded uranium with cyclotron-produced moderated (slow) neutrons, resulting not in “fission” but "fusion" of the reactants forming the new element 93, which they named "neptunium":
23892U + 10n → 23992U → 23993Np + β-
Neptunium-239 was the first transuranium element produced synthetically and the first actinide series transuranium element discovered. This isotope has a beta-decay half-life of 2.3565 days, which forms daughter product plutonium-239 with a half-life of 24,000 years.
Metallic neptunium has been prepared in visible quantities. Fresh metal is silvery, dense, and chemically reactive, but it tarnishes in air as oxide layers form. It has several solid allotropes, and bulk physical measurements are limited by radioactivity, scarcity, and self-heating.
Neptunium has no broad commercial use as an element. ²³⁷Np is used in research on actinide chemistry, nuclear fuel cycles, and long-lived radioactive waste behavior. It is also the principal target material for producing ²³⁸Pu by neutron irradiation; ²³⁸Pu is then used in radioisotope heat sources and power systems. Small quantities of neptunium compounds have been used as analytical standards and in radiochemical method development.
Neptunium's most stable isotope, neptunium-237, has a half-life of about 2,144,000 years. It decays into protactinium-233 through alpha decay. Neptunium-237, which is produced in gram quantities as a by-product of the production of plutonium in nuclear reactors, is used in neutron detectors.
Once considered to be completely artificial, extremely small amounts of neptunium are produced naturally in uranium ores through the interaction of atoms of uranium in the ore with neutrons produced by the decay of other atoms of uranium in the ore.
Isotopes in Industry
237Np (with a half-life of 2.14×106 years) is fissionable, meaning that neptunium can be bombarded with neutrons and, as a result, create more neutrons that are free to interact with nearby material and can be used in fast neutron reactors or in nuclear weapons (Fig. IUPAC.93.1) [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., [603] P. Weiss. Science News.162, 259 (2002)., [604] T. Kenna. J. Anal. At. Spectrom.17, 1471 (2002).. 237Np is used in neutron detection instruments [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..
Isotopes Used as a Source of Radioactive Isotope(s)
237Np is used in the production of 238Pu (with a half-life of 87.7 years), which is an emitter of alpha particles used in thermoelectric generators and radioisotope-heater units. When 237Np captures a neutron, it becomes 238Np, with a half-life of 2.117 days, which decays to 238Pu [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..
Neptunium forms compounds in oxidation states from +3 to +7, with +4, +5, and +6 especially important in aqueous chemistry. The neptunyl ion NpO₂⁺ is a characteristic +5 species and is often relatively mobile in oxidizing waters, while NpO₂²⁺ represents +6 chemistry. Neptunium dioxide NpO₂ is a stable refractory oxide and an important solid phase. Halides such as neptunium tetrachloride NpCl₄ and neptunium hexafluoride NpF₆ illustrate the element’s actinide-like coordination and redox behavior.
See more information at the Neptunium compound page.
All neptunium isotopes are radioactive, and hazards depend strongly on isotope, chemical form, and exposure route. ²³⁷Np emits mainly alpha radiation with associated gamma emissions from decay products, so ingestion, inhalation, or contamination of wounds is the principal concern. Finely divided metal and soluble compounds require strict radiological containment. External dose rates can be significant for some samples because of accompanying gamma-emitting impurities or daughters.
Natural neptunium is extremely scarce, but anthropogenic neptunium occurs in spent nuclear fuel, reprocessing wastes, and fallout residues. Environmental behavior is controlled by oxidation state, complexation, mineral sorption, and reducing conditions. Np(V) as NpO₂⁺ can migrate more readily than many tetravalent actinides, whereas Np(IV) tends to form less soluble solids or strongly sorbed species. Its long half-life makes it important in repository performance assessments.
Neptunium is not traded as a commodity and has no ordinary industrial supply chain. Recoverable ²³⁷Np is generated as a by-product in irradiated uranium fuel and can be separated only in specialized nuclear facilities under heavy regulation. Demand is small and centered on research inventories and on target preparation for ²³⁸Pu production. Costs are dominated by radiochemical separation, safeguards, licensing, waste management, and secure storage rather than by ore mining or conventional refining.
Produced by bombarding uranium with slow neutrons.
Neptunium has no stable isotopes, so any primordial neptunium has decayed away. It can be formed in trace amounts by neutron capture in uranium-bearing materials and in nuclear explosions or reactors, and transient neptunium isotopes may occur in astrophysical rapid neutron-capture processes. Its extraterrestrial abundance is effectively negligible compared with long-lived actinides such as uranium and thorium.
- Neptunium was named after Neptune, following uranium’s naming after Uranus.
- ²³⁷Np has a half-life of about 2.14 million years.
- Neptunium was the first element beyond uranium to be identified.
- NpF₆ is volatile, a property relevant to actinide fluoride chemistry.
- The common aqueous Np(V) ion is linear neptunyl, NpO₂⁺.
- Separated neptunium metal darkens on exposure to air.
प्रतिमा
गुणधर्म
भौतिक
- अणुत्रिज्या (अनुभवाधारित)
- 175 pm सर्व घटकांच्या अणुत्रिज्या (अनुभवाधारित) ची तुलना करा →
- सहसंयुजी त्रिज्या
- 190 pm सर्व घटकांच्या सहसंयुजी त्रिज्या ची तुलना करा →
- व्हॅन डर वाल्स त्रिज्या
- 221 pm सर्व घटकांच्या व्हॅन डर वाल्स त्रिज्या ची तुलना करा →
- घनता
- 2.025 × 104 kg/m³ सर्व घटकांच्या घनता ची तुलना करा →
- मोलर आयतन
- 0.0211 L/mol
- STP येथे अवस्था
- घन सर्व घटकांच्या STP येथे अवस्था ची तुलना करा →
- द्रवणांक
- 643.85 °C सर्व घटकांच्या द्रवणांक ची तुलना करा →
- उत्कलनांक
- 3901.85 °C सर्व घटकांच्या उत्कलनांक ची तुलना करा →
- स्फटिक संरचना
- लंबसमचतुर्भुजी सर्व घटकांच्या स्फटिक संरचना ची तुलना करा →
रासायनिक
- विद्युतऋणता (पॉलिंग)
- 1.36 सर्व घटकांच्या विद्युतऋणता (पॉलिंग) ची तुलना करा →
- इलेक्ट्रॉन आसक्ती
- 0.48 eV
- आयनीकरण ऊर्जा (पहिली)
- 6.265608 eV सर्व घटकांच्या आयनीकरण ऊर्जा (पहिली) ची तुलना करा →
- आयनीकरण ऊर्जा (दुसरी)
- 11.50004 eV सर्व घटकांच्या आयनीकरण ऊर्जा (दुसरी) ची तुलना करा →
- आयनीकरण ऊर्जा (तिसरी)
- 19.700068 eV सर्व घटकांच्या आयनीकरण ऊर्जा (तिसरी) ची तुलना करा →
- आयनीकरण ऊर्जा (चौथी)
- 33.800116 eV सर्व घटकांच्या आयनीकरण ऊर्जा (चौथी) ची तुलना करा →
- आयनीकरण ऊर्जा (पाचवी)
- 48.000165 eV सर्व घटकांच्या आयनीकरण ऊर्जा (पाचवी) ची तुलना करा →
- ऑक्सिडीकरण अवस्था
- +2, +3, +4, +5, +6, +7 सर्व घटकांच्या ऑक्सिडीकरण अवस्था ची तुलना करा →
- संयुजा इलेक्ट्रॉन
- 3 सर्व घटकांच्या संयुजा इलेक्ट्रॉन ची तुलना करा →
- इलेक्ट्रॉन संरूपण
- [Rn] 7s2 5f4 6d1
उष्मागतिक
- द्रवण उष्मा
- 0.10364305 eV सर्व घटकांच्या द्रवण उष्मा ची तुलना करा →
- बाष्पीभवन उष्मा
- 3.482407 eV सर्व घटकांच्या बाष्पीभवन उष्मा ची तुलना करा →
- संप्लवन उष्मा
- 4.33228 eV
- अणूकरण उष्मा
- 4.33228 eV
- अणूकरण एन्थाल्पी
- 4.817329 eV
केंद्रकीय
- प्रोटॉन
- 93 सर्व घटकांच्या प्रोटॉन ची तुलना करा →
- न्यूट्रॉन
- 144 सर्व घटकांच्या न्यूट्रॉन ची तुलना करा →
- ज्ञात समस्थानिके
- 27 सर्व घटकांच्या ज्ञात समस्थानिके ची तुलना करा →
- स्थिर समस्थानिके
- 0 सर्व घटकांच्या स्थिर समस्थानिके ची तुलना करा →
- वस्तुमानांक (सर्वाधिक स्थिर)
- 237
- सर्वाधिक स्थिर समस्थानिक
- Np-237
- शोधाचे वर्ष
- 1940
विपुलता
उपलब्ध नाही
स्फटिक संरचना
- जालक स्थिरांक a
- 472 pm
इलेक्ट्रॉन संरचना
- प्रत्येक कवचातील इलेक्ट्रॉन
- 2, 8, 18, 32, 22, 9, 2 सर्व घटकांच्या प्रत्येक कवचातील इलेक्ट्रॉन ची तुलना करा →
ओळखचिन्हे
- CAS क्रमांक
- 7439-99-8 सर्व घटकांच्या CAS क्रमांक ची तुलना करा →
- टर्म चिन्ह
- 6L11/2
- InChI
- InChI=1S/Np
- InChI की
- LFNLGNPSGWYGGD-UHFFFAOYSA-N
इलेक्ट्रॉन संरूपण मोजलेले
Np: 5f⁴ 6d¹ 7s²[Rn] 5f⁴ 6d¹ 7s²1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d¹⁰ 6s² 6p⁶ 5f⁴ 6d¹ 7s²अणुप्रतिमान
समस्थानिकांमुळे न्यूट्रॉन संख्या, वस्तुमान आणि स्थैर्य बदलते — विद्युतदृष्ट्या उदासीन अणूचे इलेक्ट्रॉन संरूपण बदलत नाही.
योजनात्मक अणुप्रतिमान, प्रमाणानुसार नाही.
अणूची विशिष्ट ओळख
उत्सर्जन / शोषण वर्णपट
समस्थानिक वितरण
स्थिर समस्थानिके नाहीत.
| वस्तुमानांक | अणुवस्तुमान (u) | नैसर्गिक विपुलता | अर्धायुष्य |
|---|---|---|---|
| 219 किरणोत्सारी | २१९.०३१४३ ± ०.०००२१ | उपलब्ध नाही | 570 us |
| 227 किरणोत्सारी | २२७.०३४९५७ ± ०.००००७८ | उपलब्ध नाही | 510 ms |
| 222 किरणोत्सारी | २२२.०३३३ ± ०.०००२१ | उपलब्ध नाही | 480 ns |
| 235 किरणोत्सारी | २३५.०४४०६३५ ± ०.०००००२१ | उपलब्ध नाही | 396.1 दिवस |
| 236 किरणोत्सारी | २३६.०४६५७ ± ०.००००५४ | उपलब्ध नाही | 153 ky |
अवस्था / स्थिती
कारण: द्रवणांकापेक्षा (643.85 °C) 618.9 °C कमी
योजनात्मक, प्रमाणानुसार नाही
अवस्थांतर बिंदू
अवस्थांतर ऊर्जा
द्रवणांकावर 1 mol वितळवण्यासाठी आवश्यक ऊर्जा
उत्कलनांकावर 1 mol चे बाष्पीभवन करण्यासाठी आवश्यक ऊर्जा
संप्लवनांकावर 1 mol चे संप्लवन करण्यासाठी आवश्यक ऊर्जा
घनता
प्रमाणित परिस्थितीत
प्रमाणित परिस्थितीत
अणुवर्णपट
93 पैकी 10 दाखवले आहेत. आयनाच्या विद्युतभारानुसार चढत्या क्रमाने मांडलेले.
वर्णरेषांचा संग्रह ?
| आयन | विद्युतभार | एकूण वर्णरेषा | संक्रमण संभाव्यता | पातळ्यांची नामांकने |
|---|---|---|---|---|
| Np I | 0 | 96 | 0 | 0 |
ऊर्जा पातळ्यांचा संग्रह ?
| आयन | विद्युतभार | पातळ्या |
|---|---|---|
| Np I | 0 | 2 |
| Np II | +1 | 2 |
| Np III | +2 | 2 |
| Np IV | +3 | 2 |
| Np V | +4 | 2 |
| Np VI | +5 | 2 |
| Np VII | +6 | 2 |
| Np VIII | +7 | 2 |
| Np IX | +8 | 2 |
| Np X | +9 | 2 |
आयनिक त्रिज्या
| विद्युतभार | समन्वय | प्रचक्रण | त्रिज्या |
|---|---|---|---|
| +2 | 6 | उपलब्ध नाही | 110.00000000000001 pm |
| +3 | 6 | उपलब्ध नाही | 101 pm |
| +3 | 9 | उपलब्ध नाही | 117.8 pm |
| +4 | 6 | उपलब्ध नाही | 87 pm |
| +4 | 8 | उपलब्ध नाही | 98 pm |
| +5 | 6 | उपलब्ध नाही | 75 pm |
| +6 | 6 | उपलब्ध नाही | 72 pm |
| +7 | 6 | उपलब्ध नाही | 71 pm |
संयुगे
समस्थानिके (5)
There are 25 known radioactive isotopes of neptunium ranging in atomic weights from 225 to 244 with 5 of those as metastable isotopes. The most stable are Np-237 with a half-life of 2.14 million years; Np-236 with a half-life of 154,000 years; and Np-235 with a half-life of 396 days. All of the remaining isotopes have half-lives less than 4.5 days, with most less than 50 minutes. The primary decay mode for isotopes lighter than 237Np is by electron capture with a great deal of alpha emission. The products are mostly isotopes of uranium. The primary decay mode for Np-237 is by alpha-decay forming protactinium. The primary decay mode for the isotopes heavier than Np-237 is by beta-decay, forming plutonium. Neptunium-237, after decaying to protactinium then to uranium, eventually decays to form bismuth-209 and thallium-205. Unlike most other common heavy nuclei which decay to make isotopes of lead this decay chain is known as the neptunium series.
| वस्तुमानांक | अणुवस्तुमान (u) | नैसर्गिक विपुलता | अर्धायुष्य | क्षय प्रकार | |
|---|---|---|---|---|---|
| 219 किरणोत्सारी | २१९.०३१४३ ± ०.०००२१ | उपलब्ध नाही | 570 us | α =100% | |
| 227 किरणोत्सारी | २२७.०३४९५७ ± ०.००००७८ | उपलब्ध नाही | 510 ms | α ≈100%β+ ? | |
| 222 किरणोत्सारी | २२२.०३३३ ± ०.०००२१ | उपलब्ध नाही | 480 ns | α =100% | |
| 235 किरणोत्सारी | २३५.०४४०६३५ ± ०.०००००२१ | उपलब्ध नाही | 396.1 दिवस | ε =99.99740±1.3%α =0.00260±1.3% | |
| 236 किरणोत्सारी | २३६.०४६५७ ± ०.००००५४ | उपलब्ध नाही | 153 ky | ε =86.3±0.8%β- =13.5±0.8%α =0.16±0.4% |
विस्तारित गुणधर्म
सहसंयुजी त्रिज्या (विस्तारित)
- सहसंयुजी त्रिज्या (प्युक्को)
- 171 pm
- सहसंयुजी त्रिज्या (प्युक्को, दुहेरी बंध)
- 136 pm
- सहसंयुजी त्रिज्या (प्युक्को, तिहेरी बंध)
- 116 pm
व्हॅन डर वाल्स त्रिज्या
- Alvarez
- 282 pm
- UFF
- 342.4 pm
- MM3
- 252 pm
अणुत्रिज्या आणि धात्विक त्रिज्या
- अणुत्रिज्या (राह्म)
- 281 pm
क्रमांकन मापनपट्ट्या
- Mendeleev
- 22
- Pettifor
- 44
- Glawe
- 37
विद्युतऋणता मापनपट्ट्या
- Ghosh
- 0
ध्रुवणक्षमता आणि अपस्करण
- द्विध्रुव ध्रुवणक्षमता
- 151 a.u.
- द्विध्रुव ध्रुवणक्षमता (अनिश्चितता)
- 20 a.u.
अवस्थांतरे आणि अपरूपे
| द्रवणांक | 917.15 K |
ऑक्सिडीकरण अवस्थांचे वर्ग
प्रगत संदर्भ माहिती
स्फटिक त्रिज्यांचा तपशील (8)
| विद्युतभार | CN | प्रचक्रण | rcrystal (pm) | उत्पत्ती |
|---|---|---|---|---|
| 2 | VI | 124 | ||
| 3 | VI | 115 | from r^3 vs V plots, | |
| 4 | VI | 101 | from r^3 vs V plots, | |
| 4 | VIII | 112 | from r^3 vs V plots, | |
| 5 | VI | 89 | ||
| 6 | VI | 86 | from r^3 vs V plots, | |
| 7 | VI | 85 | Ahrens (1952) ionic radius, | |
| 3 | IX | — | 131.8 |
समस्थानिक क्षय प्रकार (44)
| समस्थानिक | मोड | तीव्रता |
|---|---|---|
| 219 | A | 100% |
| 220 | A | 100% |
| 221 | A | — |
| 222 | A | 100% |
| 223 | A | 100% |
| 224 | A | 100% |
| 225 | A | 100% |
| 225 | B+ | — |
| 226 | A | 100% |
| 226 | B+ | — |
अतिरिक्त माहिती
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
Not Applicable
संदर्भ (1)
- [5] Neptunium https://education.jlab.org/itselemental/ele093.html
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
Not Applicable
संदर्भ (1)
- [5] Neptunium https://education.jlab.org/itselemental/ele093.html
संदर्भ
(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 Neptunium.
The element property data was retrieved from publications.