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93-447: Einsteinium is a synthetic chemical element ; it has symbol Es and atomic number 99. It is named after Albert Einstein and is a member of the actinide series and the seventh transuranium element . Einsteinium was discovered as a component of the debris of the first hydrogen bomb explosion in 1952. Its most common isotope , einsteinium-253 (Es; half-life 20.47 days), is produced artificially from decay of californium -253 in

186-422: A face-centered cubic ( fcc ) symmetry with the space group Fm 3 m and the lattice constant a = 575 pm . However, there is a report of room-temperature hexagonal einsteinium metal with a = 398 pm and c = 650 pm , which converted to the fcc phase upon heating to 300 °C. The self-damage induced by the radioactivity of einsteinium is so strong that it rapidly destroys the crystal lattice, and

279-416: A mass number that is reduced by four and an atomic number that is reduced by two. An alpha particle is identical to the nucleus of a helium-4 atom, which consists of two protons and two neutrons . It has a charge of +2  e and a mass of 4  Da . For example, uranium-238 decays to form thorium-234 . While alpha particles have a charge +2  e , this is not usually shown because

372-403: A proton or a neutron , and those with mass 8 decay to two helium-4 nuclei; their half-lives ( helium-5 , lithium-5 , and beryllium-8 ) are very short, unlike the half-lives for all other such nuclides with A  ≤ 209, which are very long. (Such nuclides with A  ≤ 209 are primordial nuclides except Sm.) Working out the details of the theory leads to an equation relating

465-591: A German team: bohrium , hassium , meitnerium , darmstadtium , roentgenium , and copernicium . Element 113, nihonium , was created by a Japanese team; the last five known elements, flerovium , moscovium , livermorium , tennessine , and oganesson , were created by Russian–American collaborations and complete the seventh row of the periodic table. The following elements do not occur naturally on Earth. All are transuranium elements and have atomic numbers of 95 and higher. All elements with atomic numbers 1 through 94 occur naturally at least in trace quantities, but

558-669: A cation-exchange resin column using a 90% water/10% ethanol solution saturated with hydrochloric acid (HCl) as eluant . It is usually followed by anion-exchange chromatography using 6 molar HCl as eluant. A cation-exchange resin column (Dowex-50 exchange column) treated with ammonium salts is then used to separate fractions containing elements 99, 100 and 101. These elements can be then identified simply based on their elution position/time, using α-hydroxyisobutyrate solution (α-HIB), for example, as eluant. The 3+ actinides can also be separated via solvent extraction chromatography, using bis-(2-ethylhexyl) phosphoric acid (abbreviated as HDEHP) as

651-447: A certain Es 2 O 3 phase depends on the preparation technique and sample history, and there is no clear phase diagram. Interconversions between the three phases can occur spontaneously, as a result of self-irradiation or self-heating. The hexagonal phase is isotypic with lanthanum oxide where the Es ion is surrounded by a 6-coordinated group of O ions. Einsteinium halides are known for

744-462: A few centimeters of air . Approximately 99% of the helium produced on Earth is the result of the alpha decay of underground deposits of minerals containing uranium or thorium . The helium is brought to the surface as a by-product of natural gas production. Alpha particles were first described in the investigations of radioactivity by Ernest Rutherford in 1899, and by 1907 they were identified as He ions. By 1928, George Gamow had solved

837-432: A few dedicated high-power nuclear reactors with a total yield on the order of one milligram per year. The reactor synthesis is followed by a complex process of separating einsteinium-253 from other actinides and products of their decay. Other isotopes are synthesized in various laboratories, but in much smaller amounts, by bombarding heavy actinide elements with light ions. Due to the small amounts of einsteinium produced and

930-418: A high linear energy transfer (LET) coefficient, which is about one ionization of a molecule/atom for every angstrom of travel by the alpha particle. The RBE has been set at the value of 20 for alpha radiation by various government regulations. The RBE is set at 10 for neutron irradiation, and at 1 for beta radiation and ionizing photons. However, the recoil of the parent nucleus (alpha recoil) gives it

1023-540: A higher vapor pressure than lithium fluoride . This makes this reduction reaction rather inefficient. It was tried in the early preparation attempts and quickly abandoned in favor of reduction of einsteinium(III) oxide with lanthanum metal: Einsteinium(III) oxide (Es 2 O 3 ) was obtained by burning einsteinium(III) nitrate. It forms colorless cubic crystals, which were first characterized from microgram samples sized about 30 nanometers. Two other phases, monoclinic and hexagonal, are known for this oxide. The formation of

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1116-421: A microsecond, or about 10 neutrons/(cm·s). In comparison, the flux of HFIR is 5 × 10 neutrons/(cm·s). A dedicated laboratory was set up right at Enewetak Atoll for preliminary analysis of debris, as some isotopes could have decayed by the time the debris samples reached the mainland U.S. The laboratory was receiving samples for analysis as soon as possible, from airplanes equipped with paper filters which flew over

1209-399: A mixed plutonium-neptunium charge, but they were less successful in terms of yield and was attributed to stronger losses of heavy isotopes due to enhanced fission rates in heavy-element charges. Product isolation was problematic as the explosions were spreading debris through melting and vaporizing the surrounding rocks at depths of 300–600 meters. Drilling to such depths to extract the products

1302-576: A nuclear equation describes a nuclear reaction without considering the electrons – a convention that does not imply that the nuclei necessarily occur in neutral atoms. Alpha decay typically occurs in the heaviest nuclides . Theoretically, it can occur only in nuclei somewhat heavier than nickel (element 28), where the overall binding energy per nucleon is no longer a maximum and the nuclides are therefore unstable toward spontaneous fission-type processes. In practice, this mode of decay has only been observed in nuclides considerably heavier than nickel, with

1395-423: A nucleus, that is in constant motion but held within the nucleus by strong interaction. At each collision with the repulsive potential barrier of the electromagnetic force, there is a small non-zero probability that it will tunnel its way out. An alpha particle with a speed of 1.5×10  m/s within a nuclear diameter of approximately 10  m will collide with the barrier more than 10 times per second. However, if

1488-492: A potential barrier whose walls are 25 MeV above the potential at infinity. However, decay alpha particles only have energies of around 4 to 9 MeV above the potential at infinity, far less than the energy needed to overcome the barrier and escape. Quantum mechanics, however, allows the alpha particle to escape via quantum tunneling. The quantum tunneling theory of alpha decay, independently developed by George Gamow and by Ronald Wilfred Gurney and Edward Condon in 1928,

1581-477: A process is needed to explain the existence of many stable elements in the universe. Meanwhile, isotopes of element 99 (as well as of new element 100, fermium ) were produced in the Berkeley and Argonne laboratories, in a nuclear reaction between nitrogen -14 and uranium-238, and later by intense neutron irradiation of plutonium or californium : These results were published in several articles in 1954 with

1674-438: A significant amount of energy, which also causes ionization damage (see ionizing radiation ). This energy is roughly the weight of the alpha ( 4  Da ) divided by the weight of the parent (typically about 200 Da) times the total energy of the alpha. By some estimates, this might account for most of the internal radiation damage, as the recoil nucleus is part of an atom that is much larger than an alpha particle, and causes

1767-588: A single proton or neutron or other atomic nuclei . Part of the reason is the high binding energy of the alpha particle, which means that its mass is less than the sum of the masses of two free protons and two free neutrons. This increases the disintegration energy. Computing the total disintegration energy given by the equation E d i = ( m i − m f − m p ) c 2 , {\displaystyle E_{di}=(m_{\text{i}}-m_{\text{f}}-m_{\text{p}})c^{2},} where m i

1860-412: A single proton emission would require 6.1 MeV. Most of the disintegration energy becomes the kinetic energy of the alpha particle, although to fulfill conservation of momentum , part of the energy goes to the recoil of the nucleus itself (see atomic recoil ). However, since the mass numbers of most alpha-emitting radioisotopes exceed 210, far greater than the mass number of the alpha particle (4),

1953-680: A tricapped trigonal prism geometry. Einsteinium(III) bromide (EsBr 3 ) is a pale-yellow solid with a monoclinic structure of AlCl 3 type , where the einsteinium atoms are octahedrally coordinated by bromine (coordination number 6). The divalent compounds of einsteinium are obtained by reducing the trivalent halides with hydrogen : Einsteinium(II) chloride (EsCl 2 ), einsteinium(II) bromide (EsBr 2 ), and einsteinium(II) iodide (EsI 2 ) have been produced and characterized by optical absorption, with no structural information available yet. Known oxyhalides of einsteinium include EsOCl, EsOBr and EsOI. These salts are synthesized by treating

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2046-509: A trihalide with a vapor mixture of water and the corresponding hydrogen halide: for example, EsCl 3 + H 2 O/HCl to obtain EsOCl. Einsteinium's high radioactivity has a potential use in radiation therapy , and organometallic complexes have been synthesized in order to deliver einsteinium to an appropriate organ in the body. Experiments have been performed on injecting einsteinium citrate (as well as fermium compounds) to dogs. Einsteinium(III)

2139-408: A very dense trail of ionization; the atom is typically a heavy metal , which preferentially collect on the chromosomes . In some studies, this has resulted in an RBE approaching 1,000 instead of the value used in governmental regulations. The largest natural contributor to public radiation dose is radon , a naturally occurring, radioactive gas found in soil and rock. If the gas is inhaled, some of

2232-583: Is 9.89 kilograms for a bare sphere of Es, and can be lowered to 2.9 kg by adding a 30-centimeter-thick steel neutron reflector , or even to 2.26 kg with a 20-cm-thick reflector made of water. However, even this small critical mass far exceeds the total amount of einsteinium isolated so far, especially of the rare Es. Due to the short half-life of all isotopes of einsteinium, any primordial einsteinium—that is, einsteinium that could have been present on Earth at its formation—has long since decayed. Synthesis of einsteinium from naturally-occurring uranium and thorium in

2325-520: Is a synthetic, silvery, radioactive metal. In the periodic table , it is located to the right of the actinide californium , to the left of the actinide fermium and below the lanthanide holmium with which it shares many similarities in physical and chemical properties. Its density of 8.84 g/cm is lower than that of californium (15.1 g/cm) and is nearly the same as that of holmium (8.79 g/cm), despite einsteinium being much heavier per atom than holmium. Einsteinium's melting point (860 °C)

2418-417: Is also relatively low – below californium (900 °C), fermium (1527 °C) and holmium (1461 °C). Einsteinium is a soft metal, with a bulk modulus of only 15 GPa, one of the lowest among non- alkali metals . Unlike the lighter actinides californium , berkelium , curium and americium , which crystallize in a double hexagonal structure at ambient conditions; einsteinium is believed to have

2511-555: Is available only in minute quantities, not in bulk. Einsteinium is the element with the highest atomic number which has been observed in macroscopic quantities in its pure form as einsteinium-253. Like all synthetic transuranium elements, isotopes of einsteinium are very radioactive and are considered highly dangerous to health on ingestion. Einsteinium was first identified in December 1952 by Albert Ghiorso and co-workers at University of California, Berkeley in collaboration with

2604-500: Is hexagonal, as in californium(III) fluoride (CfF 3 ) where the Es ions are 8-fold coordinated by fluorine ions in a bicapped trigonal prism arrangement. Es(III) chloride (EsCl 3 ) can be prepared by annealing Es(III) oxide in the atmosphere of dry hydrogen chloride vapors at about 500°C for some 20 minutes. It crystallizes upon cooling at about 425°C into an orange solid with a hexagonal structure of UCl 3 type , where einsteinium atoms are 9-fold coordinated by chlorine atoms in

2697-458: Is important, because the most common einsteinium isotope produced in nuclear reactors, Es, decays with a half-life of only 20 days to Bk, which is fast on the timescale of most experiments. Such separation relies on the fact that berkelium easily oxidizes to the solid +4 state and precipitates, whereas other actinides, including einsteinium, remain in their +3 state in solutions. Trivalent actinides can be separated from lanthanide fission products by

2790-491: Is no "natural isotope abundance". Therefore, for synthetic elements the total nucleon count ( protons plus neutrons ) of the most stable isotope , i.e., the isotope with the longest half-life —is listed in brackets as the atomic mass. The first element to be synthesized, rather than discovered in nature, was technetium in 1937. This discovery filled a gap in the periodic table , and the fact that technetium has no stable isotopes explains its natural absence on Earth (and

2883-451: Is no published research confirming whether the theorized einsteinium signatures proposed to be found in the star's spectrum match the lab-determined results. Einsteinium is produced in minute quantities by bombarding lighter actinides with neutrons in dedicated high-flux nuclear reactors . The world's major irradiation sources are the 85-megawatt High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL), Tennessee, U.S., and

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2976-443: Is pointed out that disintegration is a natural consequence of the laws of quantum mechanics without any special hypothesis... Much has been written of the explosive violence with which the α-particle is hurled from its place in the nucleus. But from the process pictured above, one would rather say that the α-particle almost slips away unnoticed. The theory supposes that the alpha particle can be considered an independent particle within

3069-508: Is simply washed off the foil after the irradiation. However, the produced amounts in such experiments are relatively low. The yields are much higher for reactor irradiation, but there, the product is a mixture of various actinide isotopes, as well as lanthanides produced in the nuclear fission decays. In this case, isolation of einsteinium is a tedious procedure which involves several repeating steps of cation exchange, at elevated temperature and pressure, and chromatography. Separation from berkelium

3162-441: Is the initial mass of the nucleus, m f is the mass of the nucleus after particle emission, and m p is the mass of the emitted (alpha-)particle, one finds that in certain cases it is positive and so alpha particle emission is possible, whereas other decay modes would require energy to be added. For example, performing the calculation for uranium-232 shows that alpha particle emission releases 5.4 MeV of energy, while

3255-538: Is typically not harmful, as alpha particles are effectively shielded by a few centimeters of air, a piece of paper, or the thin layer of dead skin cells that make up the epidermis ; however, many alpha sources are also accompanied by beta-emitting radio daughters, and both are often accompanied by gamma photon emission. Relative biological effectiveness (RBE) quantifies the ability of radiation to cause certain biological effects, notably either cancer or cell-death , for equivalent radiation exposure. Alpha radiation has

3348-585: The Argonne and Los Alamos National Laboratories, in the fallout from the Ivy Mike nuclear test. The test was done on November 1, 1952, at Enewetak Atoll in the Pacific Ocean and was the first successful test of a thermonuclear weapon . Initial examination of the debris from the explosion had shown the production of a new isotope of plutonium , 94 Pu , which could only have formed by

3441-487: The mass number without changing the atomic number of the nuclide, and the concomitant beta-decays resulted in a gradual increase in the atomic number: Some U atoms, however, could absorb two additional neutrons (for a total of 17), resulting in Es, as well as in the Fm isotope of another new element, fermium . The discovery of the new elements and the associated new data on multiple neutron capture were initially kept secret on

3534-400: The speed of light . There is surprisingly small variation around this energy, due to the strong dependence of the half-life of this process on the energy produced. Because of their relatively large mass, the electric charge of +2  e and relatively low velocity, alpha particles are very likely to interact with other atoms and lose their energy, and their forward motion can be stopped by

3627-534: The +2 oxidation state is also accessible, especially in solids. The high radioactivity of Es produces a visible glow and rapidly damages its crystalline metal lattice, with released heat of about 1000 watts per gram. Studying its properties is difficult due to Es's decay to berkelium -249 and then californium-249 at a rate of about 3% per day. The longest-lived isotope of einsteinium, Es (half-life 471.7 days) would be more suitable for investigation of physical properties, but it has proven far more difficult to produce and

3720-442: The Berkeley team was given the privilege to name the new elements. As the effort which had led to the design of Ivy Mike was codenamed Project PANDA, element 99 had been jokingly nicknamed "Pandemonium" but the official names suggested by the Berkeley group derived from two prominent scientists, Einstein and Fermi: "We suggest for the name for the element with the atomic number 99, einsteinium (symbol E) after Albert Einstein and for

3813-542: The Earth formed (about 4.6 billion years ago) have long since decayed. Synthetic elements now present on Earth are the product of atomic bombs or experiments that involve nuclear reactors or particle accelerators , via nuclear fusion or neutron absorption . Atomic mass for natural elements is based on weighted average abundance of natural isotopes in Earth 's crust and atmosphere . For synthetic elements, there

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3906-493: The Earth's crust requires multiple neutron capture, an extremely unlikely event. Therefore, all einsteinium on Earth is produced in laboratories, high-power nuclear reactors, or nuclear testing , and exists only within a few years from the time of the synthesis. The transuranic elements americium to fermium , including einsteinium, were once created in the natural nuclear fission reactor at Oklo , but any quantities produced then would have long since decayed away. Einsteinium

3999-811: The EsF 3 , which are the highest values among actinides, and the corresponding Curie temperatures are 53 and 37 K. Like all actinides, einsteinium is rather reactive. Its trivalent oxidation state is most stable in solids and aqueous solution where it induces a pale pink color. The existence of divalent einsteinium is firmly established, especially in the solid phase; such +2 state is not observed in many other actinides, including protactinium , uranium , neptunium , plutonium , curium and berkelium . Einsteinium(II) compounds can be obtained, for example, by reducing einsteinium(III) with samarium(II) chloride . Eighteen isotopes and four nuclear isomers are known for einsteinium, with mass numbers 240–257. All are radioactive;

4092-844: The SM-2 loop reactor at the Research Institute of Atomic Reactors (NIIAR) in Dimitrovgrad, Russia , which are both dedicated to the production of transcurium ( Z >96) elements. These facilities have similar power and flux levels, and are expected to have comparable production capacities for transcurium elements, though the quantities produced at NIIAR are not widely reported. In a "typical processing campaign" at ORNL, tens of grams of curium are irradiated to produce decigram quantities of californium , milligrams of berkelium (Bk) and einsteinium and picograms of fermium . The first microscopic sample of Es sample weighing about 10 nanograms

4185-456: The Swedish group succeeded in synthesizing light isotopes of element 100, in particular Fm, by bombarding uranium with oxygen nuclei. These results were also published in 1954. Nevertheless, the priority of the Berkeley team was generally recognized, as its publications preceded the Swedish article, and they were based on the previously undisclosed results of the 1952 thermonuclear explosion; thus

4278-415: The absorption of six neutrons by a uranium-238 nucleus followed by two beta decays . At the time, the multiple neutron absorption was thought to be an extremely rare process, but the identification of Pu indicated that still more neutrons could have been captured by the uranium, producing new elements heavier than californium . Ghiorso and co-workers analyzed filter papers which had been flown through

4371-468: The air, allowing the "static cling" to dissipate more rapidly. Highly charged and heavy, alpha particles lose their several MeV of energy within a small volume of material, along with a very short mean free path . This increases the chance of double-strand breaks to the DNA in cases of internal contamination, when ingested, inhaled, injected or introduced through the skin. Otherwise, touching an alpha source

4464-408: The alpha particle. Like other cluster decays, alpha decay is fundamentally a quantum tunneling process. Unlike beta decay , it is governed by the interplay between both the strong nuclear force and the electromagnetic force . Alpha particles have a typical kinetic energy of 5 MeV (or ≈ 0.13% of their total energy, 110 TJ/kg) and have a speed of about 15,000,000 m/s, or 5% of

4557-638: The atoll after the tests. Whereas it was hoped to discover new chemical elements heavier than fermium, none of these were found even after a series of megaton explosions conducted between 1954 and 1956 at the atoll. The atmospheric results were supplemented by the underground test data accumulated in the 1960s at the Nevada Test Site , as it was hoped that powerful explosions in a confined space might give improved yields and heavier isotopes. Apart from traditional uranium charges, combinations of uranium with americium and thorium have been tried, as well as

4650-474: The contamination problem include selective optical excitation of einsteinium ions by a tunable laser, such as in studying its luminescence properties. Magnetic properties have been studied for einsteinium metal, its oxide and fluoride. All three materials showed Curie–Weiss paramagnetic behavior from liquid helium to room temperature. The effective magnetic moments were deduced as 10.4 ± 0.3  μ B for Es 2 O 3 and 11.4 ± 0.3  μ B for

4743-556: The disclaimer that these were not the first studies that had been carried out on the elements. The Berkeley team also reported some results on the chemical properties of einsteinium and fermium. The Ivy Mike results were declassified and published in 1955. In their discovery of elements 99 and 100, the American teams had competed with a group at the Nobel Institute for Physics, Stockholm , Sweden . In late 1953 – early 1954,

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4836-570: The end. Nevertheless, element 99, einsteinium, and in particular Es, could be detected via its characteristic high-energy alpha decay at 6.6 MeV. It was produced by the capture of 15 neutrons by uranium-238 nuclei followed by seven beta decays, and had a half-life of 20.5 days. Such multiple neutron absorption was made possible by the high neutron flux density during the detonation, so that newly generated heavy isotopes had plenty of available neutrons to absorb before they could disintegrate into lighter elements. Neutron capture initially raised

4929-409: The energy release during this process, 1000 watts per gram of Es, induces a visible glow. These processes may contribute to the relatively low density and melting point of einsteinium. Further, due to the small size of available samples, the melting point of einsteinium was often deduced by observing the sample being heated inside an electron microscope. Thus, surface effects in small samples could reduce

5022-487: The explosion cloud on airplanes (the same sampling technique that had been used to discover Pu). Larger amounts of radioactive material were later isolated from coral debris of the atoll, and these were delivered to the U.S. The separation of suspected new elements was carried out in the presence of a citric acid / ammonium buffer solution in a weakly acidic medium ( pH ≈ 3.5), using ion exchange at elevated temperatures; fewer than 200 atoms of einsteinium were recovered in

5115-672: The first hydrogen bomb. The isotopes synthesized were einsteinium-253, with a half-life of 20.5 days, and fermium-255 , with a half-life of about 20 hours. The creation of mendelevium , nobelium , and lawrencium followed. During the height of the Cold War , teams from the Soviet Union and the United States independently created rutherfordium and dubnium . The naming and credit for synthesis of these elements remained unresolved for many years , but eventually, shared credit

5208-415: The following elements are often produced through synthesis. Technetium, promethium, astatine, neptunium, and plutonium were discovered through synthesis before being found in nature. Alpha decay Alpha decay or α-decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle ( helium nucleus) and thereby transforms or "decays" into a different atomic nucleus, with

5301-517: The fraction of the energy going to the recoil of the nucleus is generally quite small, less than 2%. Nevertheless, the recoil energy (on the scale of keV) is still much larger than the strength of chemical bonds (on the scale of eV), so the daughter nuclide will break away from the chemical environment the parent was in. The energies and ratios of the alpha particles can be used to identify the radioactive parent via alpha spectrometry . These disintegration energies, however, are substantially smaller than

5394-426: The gap). With the longest-lived isotope of technetium, Tc, having a 4.21-million-year half-life, no technetium remains from the formation of the Earth. Only minute traces of technetium occur naturally in Earth's crust—as a product of spontaneous fission of U, or from neutron capture in molybdenum —but technetium is present naturally in red giant stars. The first entirely synthetic element to be made

5487-403: The half-life of a radioisotope to the decay energy of its alpha particles, a theoretical derivation of the empirical Geiger–Nuttall law . Americium-241 , an alpha emitter , is used in smoke detectors . The alpha particles ionize air in an open ion chamber and a small current flows through the ionized air. Smoke particles from the fire that enter the chamber reduce the current, triggering

5580-461: The lightest known alpha emitter being the second lightest isotope of antimony , Sb . Exceptionally, however, beryllium-8 decays to two alpha particles. Alpha decay is by far the most common form of cluster decay , where the parent atom ejects a defined daughter collection of nucleons, leaving another defined product behind. It is the most common form because of the combined extremely high nuclear binding energy and relatively small mass of

5673-417: The melting point. The metal is trivalent and has a noticeably high volatility. In order to reduce the self-radiation damage, most measurements of solid einsteinium and its compounds are performed right after thermal annealing. Also, some compounds are studied under the atmosphere of the reductant gas, for example H 2 O+ HCl for EsOCl so that the sample is partly regrown during its decomposition. Apart from

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5766-415: The most stable one, Es, has half-life 471.7 days. The next most stable isotopes are Es (half-life 275.7 days), Es (39.8 days), and Es (20.47 days). All the other isotopes have half-lives shorter than 40 hours, most shorter than 30 minutes. Of the five isomers, the most stable is Es with a half-life of 39.3 hours. Einsteinium has a high rate of nuclear fission that results in a low critical mass . This mass

5859-437: The name for the element with atomic number 100, fermium (symbol Fm), after Enrico Fermi ." Both Einstein and Fermi died between the time the names were originally proposed and when they were announced. The discovery of these new elements was announced by Albert Ghiorso at the first Geneva Atomic Conference held on 8–20 August 1955. The symbol for einsteinium was first given as "E" and later changed to "Es" by IUPAC. Einsteinium

5952-413: The nuclear test debris, and the total yields of transuranics were disappointingly low, these tests did provide significantly higher amounts of rare heavy isotopes than previously available in laboratories. Separation procedure of einsteinium depends on the synthesis method. In the case of light-ion bombardment inside a cyclotron, the heavy ion target is attached to a thin foil, and the generated einsteinium

6045-482: The nucleus apart is roughly proportional to the square of its atomic number. A nucleus with 210 or more nucleons is so large that the strong nuclear force holding it together can just barely counterbalance the electromagnetic repulsion between the protons it contains. Alpha decay occurs in such nuclei as a means of increasing stability by reducing size. One curiosity is why alpha particles, helium nuclei, should be preferentially emitted as opposed to other particles like

6138-425: The orders of the U.S. military until 1955 due to Cold War tensions and competition with Soviet Union in nuclear technologies. However, the rapid capture of so many neutrons would provide needed direct experimental confirmation of the r-process multi-neutron absorption needed to explain the cosmic nucleosynthesis (production) of certain heavy elements (heavier than nickel) in supernovas , before beta decay . Such

6231-457: The other side to escape the nucleus. Gamow solved a model potential for the nucleus and derived, from first principles, a relationship between the half-life of the decay, and the energy of the emission, which had been previously discovered empirically and was known as the Geiger–Nuttall law . The nuclear force holding an atomic nucleus together is very strong, in general much stronger than

6324-435: The oxidation states +2 and +3. The most stable state is +3 for all halides from fluoride to iodide. Einsteinium(III) fluoride (EsF 3 ) can be precipitated from Es(III) chloride solutions upon reaction with fluoride ions. An alternative preparation procedure is to exposure Es(III) oxide to chlorine trifluoride (ClF 3 ) or F 2 gas at a pressure of 1–2 atmospheres and temperature 300–400°C. The EsF 3 crystal structure

6417-705: The probability of escape at each collision is very small, the half-life of the radioisotope will be very long, since it is the time required for the total probability of escape to reach 50%. As an extreme example, the half-life of the isotope bismuth-209 is 2.01 × 10  years . The isotopes in beta-decay stable isobars that are also stable with regards to double beta decay with mass number A  = 5, A  = 8, 143 ≤  A  ≤ 155, 160 ≤  A  ≤ 162, and A  ≥ 165 are theorized to undergo alpha decay. All other mass numbers ( isobars ) have exactly one theoretically stable nuclide . Those with mass 5 decay to helium-4 and

6510-464: The radioactive debris dispersed by the powerful blast. Aircraft filters adsorbed only ~4 × 10 of the total amount, and collection of tons of corals at Enewetak Atoll increased this fraction by only two orders of magnitude. Extraction of about 500 kilograms of underground rocks 60 days after the Hutch explosion recovered only ~1 × 10 of the total charge. The amount of transuranic elements in this 500-kg batch

6603-622: The radon particles may attach to the inner lining of the lung. These particles continue to decay, emitting alpha particles, which can damage cells in the lung tissue. The death of Marie Curie at age 66 from aplastic anemia was probably caused by prolonged exposure to high doses of ionizing radiation, but it is not clear if this was due to alpha radiation or X-rays. Curie worked extensively with radium, which decays into radon, along with other radioactive materials that emit beta and gamma rays . However, Curie also worked with unshielded X-ray tubes during World War I, and analysis of her skeleton during

6696-436: The repulsive electromagnetic forces between the protons. However, the nuclear force is also short-range, dropping quickly in strength beyond about 3 femtometers , while the electromagnetic force has an unlimited range. The strength of the attractive nuclear force keeping a nucleus together is thus proportional to the number of the nucleons, but the total disruptive electromagnetic force of proton-proton repulsion trying to break

6789-427: The repulsive potential barrier created by the interplay between the strong nuclear and the electromagnetic force, which prevents the alpha particle from escaping. The energy needed to bring an alpha particle from infinity to a point near the nucleus just outside the range of the nuclear force's influence is generally in the range of about 25 MeV. An alpha particle within the nucleus can be thought of as being inside

6882-565: The self-destruction of solid einsteinium and its compounds, other intrinsic difficulties in studying this element include scarcity – the most common Es isotope is available only once or twice a year in sub-milligram amounts – and self-contamination due to rapid conversion of einsteinium to berkelium and then to californium at a rate of about 3.3% per day: Thus, most einsteinium samples are contaminated, and their intrinsic properties are often deduced by extrapolating back experimental data accumulated over time. Other experimental techniques to circumvent

6975-400: The short half-life of its most common isotope, there are no practical applications for it except basic scientific research. In particular, einsteinium was used to synthesize, for the first time, 17 atoms of the new element mendelevium in 1955. Einsteinium is a soft, silvery, paramagnetic metal. Its chemistry is typical of the late actinides, with a preponderance of the +3 oxidation state ;

7068-481: The smoke detector's alarm. Radium-223 is also an alpha emitter . It is used in the treatment of skeletal metastases (cancers in the bones). Alpha decay can provide a safe power source for radioisotope thermoelectric generators used for space probes and were used for artificial heart pacemakers . Alpha decay is much more easily shielded against than other forms of radioactive decay. Static eliminators typically use polonium-210 , an alpha emitter, to ionize

7161-620: The stationary organic phase, and nitric acid as the mobile aqueous phase. The actinide elution sequence is reversed from that of the cation-exchange resin column. The einsteinium separated by this method has the advantage to be free of organic complexing agent, as compared to the separation using a resin column. Einsteinium is highly reactive, so strong reducing agents are required to obtain the pure metal from its compounds. This can be achieved by reduction of einsteinium(III) fluoride with metallic lithium : However, owing to its low melting point and high rate of self-radiation damage, einsteinium has

7254-446: The surface. This method was tried in two tests and instantly provided hundreds of kilograms of material, but with actinide concentration 3 times lower than in samples obtained after drilling. Whereas such method could have been efficient in scientific studies of short-lived isotopes, it could not improve the overall collection efficiency of the produced actinides. Though no new elements (except einsteinium and fermium) could be detected in

7347-552: The target right after irradiation. Subsequent separation procedures reduced the amount of isotopically pure einsteinium roughly tenfold. Heavy neutron irradiation of plutonium results in four major isotopes of einsteinium: Es (α-emitter; half-life 20.47 days, spontaneous fission half-life 7×10 years); Es (β-emitter, half-life 39.3 hours), Es (α-emitter, half-life 276 days) and Es (β-emitter, half-life 39.8 days). An alternative route involves bombardment of uranium-238 with high-intensity nitrogen or oxygen ion beams. Es (half-life 4.55 min)

7440-402: The theory of alpha decay via tunneling. The alpha particle is trapped inside the nucleus by an attractive nuclear potential well and a repulsive electromagnetic potential barrier . Classically, it is forbidden to escape, but according to the (then) newly discovered principles of quantum mechanics , it has a tiny (but non-zero) probability of " tunneling " through the barrier and appearing on

7533-399: Was curium , synthesized in 1944 by Glenn T. Seaborg , Ralph A. James , and Albert Ghiorso by bombarding plutonium with alpha particles . Synthesis of americium , berkelium , and californium followed soon. Einsteinium and fermium were discovered by a team of scientists led by Albert Ghiorso in 1952 while studying the composition of radioactive debris from the detonation of

7626-448: Was also incorporated into β-diketone chelate complexes, since analogous complexes with lanthanides previously showed strongest UV-excited luminescence among metallorganic compounds. When preparing einsteinium complexes, the Es ions were 1000 times diluted with Gd ions. This allowed reducing the radiation damage so that the compounds did not disintegrate during the 20 minutes required for the measurements. The resulting luminescence from Es

7719-402: Was both slow and inefficient in terms of collected volumes. Of the nine underground tests between 1962 and 1969, the last one was the most powerful and had the highest yield of transuranics. Milligrams of einsteinium that would normally take a year of irradiation in a high-power reactor, were produced within a microsecond. However, the major practical problem of the entire proposal was collecting

7812-706: Was created in 1937. Plutonium (Pu, atomic number 94), first synthesized in 1940, is another such element. It is the element with the largest number of protons (atomic number) to occur in nature, but it does so in such tiny quantities that it is far more practical to synthesize it. Plutonium is known mainly for its use in atomic bombs and nuclear reactors. No elements with atomic numbers greater than 99 have any uses outside of scientific research, since they have extremely short half-lives, and thus have never been produced in large quantities. All elements with atomic number greater than 94 decay quickly enough into lighter elements such that any atoms of these that may have existed when

7905-420: Was hailed as a very striking confirmation of quantum theory. Essentially, the alpha particle escapes from the nucleus not by acquiring enough energy to pass over the wall confining it, but by tunneling through the wall. Gurney and Condon made the following observation in their paper on it: It has hitherto been necessary to postulate some special arbitrary 'instability' of the nucleus, but in the following note, it

7998-640: Was much too weak to be detected. This was explained by the unfavorable relative energies of the individual constituents of the compound that hindered efficient energy transfer from the chelate matrix to Es ions. Similar conclusion was drawn for americium, berkelium and fermium. Synthetic element Five more elements that were first created artificially are strictly speaking not synthetic because they were later found in nature in trace quantities: 43 Tc , 61 Pm , 85 At , 93 Np , and 94 Pu , though are sometimes classified as synthetic alongside exclusively artificial elements. The first, technetium,

8091-421: Was only 30 times higher than in a 0.4-kg rock picked up 7 days after the test which showed the highly non-linear dependence of the transuranics yield on the amount of retrieved radioactive rock. Shafts were drilled at the site before the test in order to accelerate sample collection after explosion, so that explosion would expel radioactive material from the epicenter through the shafts and to collecting volumes near

8184-415: Was prepared in 1961 at HFIR. A special magnetic balance was designed to estimate its weight. Larger batches were produced later starting from several kilograms of plutonium with the einsteinium yields (mostly Es) of 0.48 milligram in 1967–1970, 3.2 milligrams in 1971–1973, followed by steady production of about 3 milligrams per year between 1974 and 1978. These quantities however refer to the integral amount in

8277-682: Was produced by irradiating Am with carbon or U with nitrogen ions. The latter reaction was first realized in 1967 in Dubna, Russia, and the involved scientists were awarded the Lenin Komsomol Prize . Es was produced by irradiating Cf with deuterium ions. It mainly β-decays to Cf with a half-life of 25 ± 5 minutes, but also releases 6.87-MeV α-particles; the ratio of β's to α-particles is about 400. Es were obtained by bombarding Bk with α-particles. One to four neutrons are released, so four different isotopes are formed in one reaction. Es

8370-405: Was produced by irradiating a 0.1–0.2 milligram Cf target with a thermal neutron flux of (2–5)×10 neutrons/(cm·s) for 500–900 hours: In 2020, scientists at ORNL created about 200 nanograms of Es; allowing some chemical properties of the element to be studied for the first time. The analysis of the debris at the 10- megaton Ivy Mike nuclear test was a part of long-term project. One of the goals

8463-494: Was recognized by IUPAC / IUPAP in 1992. In 1997, IUPAC decided to give dubnium its current name honoring the city of Dubna where the Russian team worked since American-chosen names had already been used for many existing synthetic elements, while the name rutherfordium (chosen by the American team) was accepted for element 104. Meanwhile, the American team had created seaborgium , and the next six elements had been created by

8556-408: Was studying the efficiency of production of transuranic elements in high-power nuclear explosions. The motive for these experiments was that synthesis of such elements from uranium requires multiple neutron capture. The probability of such events increases with the neutron flux , and nuclear explosions are the most powerful man-made neutron sources, providing densities of the order 10 neutrons/cm within

8649-712: Was theoretically observed in the spectrum of Przybylski's Star . However, the lead author of the studies finding einsteinium and other short-lived actinides in Przybylski's Star, Vera F. Gopka, admitted that "the position of lines of the radioactive elements under search were simply visualized in synthetic spectrum as vertical markers because there are not any atomic data for these lines except for their wavelengths (Sansonetti et al. 2004), enabling one to calculate their profiles with more or less real intensities." The signature spectra of einsteinium's isotopes have since been comprehensively analyzed experimentally (in 2021), though there

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