48-456: Fajans is a surname. Notable people with the name include: Kazimierz Fajans (1887–1975), Polish American physical chemist Maksymilian Fajans (1827–1890), Polish-Jewish artist, lithographer and photographer See also [ edit ] Fajans–Paneth–Hahn Law Fajans' rules Radioactive displacement law of Fajans and Soddy [REDACTED] Surname list This page lists people with
96-498: A neutron probe – a standard device for measuring the quantity of water present in soil, as well as moisture/density for quality control in highway construction. Such probes are also used in well logging applications, in neutron radiography , tomography and other radiochemical investigations. Ac is applied in medicine to produce Bi in a reusable generator or can be used alone as an agent for radiation therapy , in particular targeted alpha therapy (TAT). This isotope has
144-404: A candidate for a near room-temperature superconductor as they have T c significantly higher than H 3 S, possibly near 250 K. Ac is highly radioactive and experiments with it are carried out in a specially designed laboratory equipped with a tight glove box . When actinium trichloride is administered intravenously to rats, about 33% of actinium is deposited into the bones and 50% into
192-560: A half of year. It decays according to its 21.772-year half-life emitting mostly beta (98.62%) and some alpha particles (1.38%); the successive decay products are part of the actinium series . Owing to the low available amounts, low energy of its beta particles (maximum 44.8 keV) and low intensity of alpha radiation, Ac is difficult to detect directly by its emission and it is therefore traced via its decay products. The isotopes of actinium range in atomic weight from 203 u ( Ac ) to 236 u ( Ac ). Actinium
240-433: A half-life of 10 days, making it much more suitable for radiation therapy than Bi (half-life 46 minutes). Additionally, Ac decays to nontoxic Bi rather than toxic lead , which is the final product in the decay chains of several other candidate isotopes, namely Th, Th, and U. Not only Ac itself, but also its daughters, emit alpha particles which kill cancer cells in the body. The major difficulty with application of Ac
288-419: A half-life of 29 hours and thus does not contaminate Ac. Actinium metal has been prepared by the reduction of actinium fluoride with lithium vapor in vacuum at a temperature between 1,100 and 1,300 °C (2,010 and 2,370 °F). Higher temperatures resulted in evaporation of the product and lower ones lead to an incomplete transformation. Lithium was chosen among other alkali metals because its fluoride
336-421: A limited number of actinium compounds are known. These include: AcF 3 , AcCl 3 , AcBr 3 , AcOF , AcOCl , AcOBr , Ac 2 S 3 , Ac 2 O 3 , AcPO 4 and Ac(NO 3 ) 3 . They all contain actinium in the oxidation state +3. In particular, the lattice constants of the analogous lanthanum and actinium compounds differ by only a few percent. Here a , b and c are lattice constants, No
384-632: A low cross-linking cation exchange resin and nitric acid as eluant . Ac was first produced artificially at the Institute for Transuranium Elements (ITU) in Germany using a cyclotron and at St George Hospital in Sydney using a linac in 2000. This rare isotope has potential applications in radiation therapy and is most efficiently produced by bombarding a radium-226 target with 20–30 MeV deuterium ions. This reaction also yields Ac which however decays with
432-539: A mixture of hydrogen sulfide and carbon disulfide on actinium oxide at 1,000 °C (1,830 °F). Naturally occurring actinium is principally composed of two radioactive isotopes ; Ac (from the radioactive family of U ) and Ac (a granddaughter of Th ). Ac decays mainly as a beta emitter with a very small energy, but in 1.38% of cases it emits an alpha particle , so it can readily be identified through alpha spectrometry . Thirty-three radioisotopes have been identified,
480-554: A radioactive lead isotope with Voigt, and a new rhenium isotope with Sullivan. He was a member of the Polish Institute of Arts and Sciences in America and of many societies and academies. Actinium Actinium is a chemical element ; it has symbol Ac and atomic number 89. It was first isolated by Friedrich Oskar Giesel in 1902, who gave it the name emanium ; the element got its name by being wrongly identified with
528-422: A solution of actinium trichloride in hydrochloric acid with ammonia . Reaction of aluminium bromide and actinium oxide yields actinium tribromide: and treating it with ammonium hydroxide at 500 °C (932 °F) results in the oxybromide AcOBr. Actinium hydride was obtained by reduction of actinium trichloride with potassium at 300 °C (572 °F), and its structure was deduced by analogy with
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#1733084549144576-438: A substance André-Louis Debierne found in 1899 and called actinium. The actinide series, a set of 15 elements between actinium and lawrencium in the periodic table , are named for actinium. Together with polonium , radium , and radon , actinium was one of the first non-primordial radioactive elements to be isolated. A soft, silvery-white radioactive metal, actinium reacts rapidly with oxygen and moisture in air forming
624-405: A white coating of actinium oxide that prevents further oxidation. As with most lanthanides and many actinides , actinium assumes oxidation state +3 in nearly all its chemical compounds. Actinium is found only in traces in uranium and thorium ores as the isotope Ac, which decays with a half-life of 21.772 years, predominantly emitting beta and sometimes alpha particles , and Ac, which
672-531: Is a soft, silvery-white, radioactive , metallic element. Its estimated shear modulus is similar to that of lead . Owing to its strong radioactivity, actinium glows in the dark with a pale blue light, which originates from the surrounding air ionized by the emitted energetic particles. Actinium has similar chemical properties to lanthanum and other lanthanides, and therefore these elements are difficult to separate when extracting from uranium ores. Solvent extraction and ion chromatography are commonly used for
720-500: Is a transient member of the thorium series decay chain, which begins with the parent isotope Th and ends with the stable lead isotope Pb . Another actinium isotope ( Ac) is transiently present in the neptunium series decay chain , beginning with Np (or U ) and ending with thallium ( Tl ) and near-stable bismuth ( Bi ); even though all primordial Np has decayed away, it is continuously produced by neutron knock-out reactions on natural U. The low natural concentration, and
768-426: Is also an efficient neutron source with the activity exceeding that of the standard americium-beryllium and radium-beryllium pairs. In all those applications, Ac (a beta source) is merely a progenitor which generates alpha-emitting isotopes upon its decay. Beryllium captures alpha particles and emits neutrons owing to its large cross-section for the (α,n) nuclear reaction: The AcBe neutron sources can be applied in
816-403: Is beta active with a half-life of 6.15 hours. One tonne of natural uranium in ore contains about 0.2 milligrams of actinium-227, and one tonne of thorium contains about 5 nanograms of actinium-228. The close similarity of physical and chemical properties of actinium and lanthanum makes separation of actinium from the ore impractical. Instead, the element is prepared, in milligram amounts, by
864-591: Is carried out at room temperature, by adding hydrofluoric acid to a solution containing actinium ions. In the latter method, actinium metal is treated with hydrogen fluoride vapors at 700 °C (1,292 °F) in an all-platinum setup. Treating actinium trifluoride with ammonium hydroxide at 900–1,000 °C (1,650–1,830 °F) yields oxyfluoride AcOF. Whereas lanthanum oxyfluoride can be easily obtained by burning lanthanum trifluoride in air at 800 °C (1,470 °F) for an hour, similar treatment of actinium trifluoride yields no AcOF and only results in melting of
912-575: Is different from Wikidata All set index articles Kazimierz Fajans Kazimierz Fajans ( Kasimir Fajans in many American publications; 27 May 1887 – 18 May 1975) was a Polish-American physical chemist, a pioneer in the science of radioactivity and the co-discoverer of chemical element protactinium . Fajans was born May 27, 1887, in Warsaw , Congress Poland , to a family of Jewish background. After he had completed secondary school in Warsaw (1904), he studied chemistry in Germany, first at
960-416: Is found only in traces in uranium ores – one tonne of uranium in ore contains about 0.2 milligrams of Ac – and in thorium ores, which contain about 5 nanograms of Ac per one tonne of thorium. The actinium isotope Ac is a transient member of the uranium-actinium series decay chain , which begins with the parent isotope U (or Pu ) and ends with the stable lead isotope Pb . The isotope Ac
1008-416: Is most volatile. Owing to its scarcity, high price and radioactivity, Ac currently has no significant industrial use, but Ac is currently being studied for use in cancer treatments such as targeted alpha therapies. Ac is highly radioactive and was therefore studied for use as an active element of radioisotope thermoelectric generators , for example in spacecraft. The oxide of Ac pressed with beryllium
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#17330845491441056-484: Is prepared, in milligram amounts, by the neutron irradiation of Ra in a nuclear reactor . The reaction yield is about 2% of the radium weight. Ac can further capture neutrons resulting in small amounts of Ac. After the synthesis, actinium is separated from radium and from the products of decay and nuclear fusion, such as thorium, polonium, lead and bismuth. The extraction can be performed with thenoyltrifluoroacetone - benzene solution from an aqueous solution of
1104-514: Is space group number and Z is the number of formula units per unit cell . Density was not measured directly but calculated from the lattice parameters. Actinium oxide (Ac 2 O 3 ) can be obtained by heating the hydroxide at 500 °C (932 °F) or the oxalate at 1,100 °C (2,010 °F), in vacuum. Its crystal lattice is isotypic with the oxides of most trivalent rare-earth metals. Actinium trifluoride can be produced either in solution or in solid reaction. The former reaction
1152-408: The surname Fajans . If an internal link intending to refer to a specific person led you to this page, you may wish to change that link by adding the person's given name (s) to the link. Retrieved from " https://en.wikipedia.org/w/index.php?title=Fajans&oldid=882023008 " Category : Surnames Hidden categories: Articles with short description Short description
1200-462: The transuranium elements (although it had been proposed as early as 1892 by British chemist Henry Bassett). Actinium reacts rapidly with oxygen and moisture in air forming a white coating of actinium oxide that impedes further oxidation. As with most lanthanides and actinides, actinium exists in the oxidation state +3, and the Ac ions are colorless in solutions. The oxidation state +3 originates from
1248-956: The Faculty of Physical Chemistry at Munich University , and in 1932 became the Head of the Institute of Physical Chemistry established by the Rockefeller Foundation . In 1935 he left Germany due to escalating Nazi persecution. He stayed for a while in Cambridge and then moved to the University of Michigan where he worked until his demise. In 1959 he became an honorary member of the Polish Chemical Society . Fajans retired at age of seventy but never stopped working. He died May 18, 1975, in Ann Arbor, Michigan . Fajans worked with Henry G. Moseley at
1296-742: The University in Leipzig , and then in Heidelberg and Zürich . In 1909 he was awarded his PhD for research into the stereoselective synthesis of chiral compounds. In 1910 Fajans took a job at the laboratory of Ernest Rutherford in Manchester , where the nucleus was discovered. He then returned to Germany, where he became an assistant and subsequently assistant professor at the Technical University of Karlsruhe , researching radioactivity. In 1917 he headed
1344-566: The [Rn] 6d 7s electronic configuration of actinium, with three valence electrons that are easily donated to give the stable closed-shell structure of the noble gas radon . Although the 5f orbitals are unoccupied in an actinium atom, it can be used as a valence orbital in actinium complexes and hence it is generally considered the first 5f element by authors working on it. Ac is the largest of all known tripositive ions and its first coordination sphere contains approximately 10.9 ± 0.5 water molecules. Due to actinium's intense radioactivity, only
1392-455: The bones, but the excretion from the body remained slow. Much better results were obtained with such chelating agents as HEHA ( 1,4,7,10,13,16-hexaazacyclohexadecane-N,N′,N″,N‴,N‴′,N‴″-hexaacetic acid ) or DOTA ( 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid ) coupled to trastuzumab , a monoclonal antibody that interferes with the HER2/neu receptor . The latter delivery combination
1440-416: The close similarity of physical and chemical properties to those of lanthanum and other lanthanides, which are always abundant in actinium-bearing ores, render separation of actinium from the ore impractical. The most concentrated actinium sample prepared from raw material consisted of 7 micrograms of Ac in less than 0.1 milligrams of La 2 O 3 , and complete separation was never achieved. Instead, actinium
1488-466: The concentration of the latter isotope does not follow the Pa depth profile, but instead increases toward the sea bottom. This occurs because of the mixing processes which raise some additional Ac from the sea bottom. Thus analysis of both Pa and Ac depth profiles allows researchers to model the mixing behavior. There are theoretical predictions that AcH x hydrides (in this case with very high pressure) are
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1536-418: The conditions of precipitation and absorption of radioactive substances. It is very significant for separation and purification of radioactive substances found in the smallest number. In 1919, Fajans began researching the structure of crystals by thermochemical and refractometric methods. The co-relation of Born, Fajans and Haber is a basic thermochemical rule. On the basis of his research data Fajans formulated
1584-737: The contradicting chemical properties he claimed for the element at different times. Articles published in the 1970s and later suggest that Debierne's results published in 1904 conflict with those reported in 1899 and 1900. Furthermore, the now-known chemistry of actinium precludes its presence as anything other than a minor constituent of Debierne's 1899 and 1900 results; in fact, the chemical properties he reported make it likely that he had, instead, accidentally identified protactinium , which would not be discovered for another fourteen years, only to have it disappear due to its hydrolysis and adsorption onto his laboratory equipment . This has led some authors to advocate that Giesel alone should be credited with
1632-474: The corresponding LaH 2 hydride. The source of hydrogen in the reaction was uncertain. Mixing monosodium phosphate (NaH 2 PO 4 ) with a solution of actinium in hydrochloric acid yields white-colored actinium phosphate hemihydrate (AcPO 4 ·0.5H 2 O), and heating actinium oxalate with hydrogen sulfide vapors at 1,400 °C (2,550 °F) for a few minutes results in a black actinium sulfide Ac 2 S 3 . It may possibly be produced by acting with
1680-413: The discovery. A less confrontational vision of scientific discovery is proposed by Adloff. He suggests that hindsight criticism of the early publications should be mitigated by the then nascent state of radiochemistry: highlighting the prudence of Debierne's claims in the original papers, he notes that nobody can contend that Debierne's substance did not contain actinium. Debierne, who is now considered by
1728-472: The essential relationships concerning chemical bond strength and deformation of ions and particles, such as heat of ion hydration, refractive index and the heat of sublimation . In 1923 he formulated Fajans' rules of inorganic chemistry , which are used to predict whether a chemical bond will be covalent or ionic . In the United States he researched nuclear reactions using a cyclotron and discovered
1776-447: The initial product. Actinium trichloride is obtained by reacting actinium hydroxide or oxalate with carbon tetrachloride vapors at temperatures above 960 °C (1,760 °F). Similarly to the oxyfluoride, actinium oxychloride can be prepared by hydrolyzing actinium trichloride with ammonium hydroxide at 1,000 °C (1,830 °F). However, in contrast to the oxyfluoride, the oxychloride could well be synthesized by igniting
1824-411: The laboratory of Ernest Rutherford researching properties of the radioactive rows of the periodic table . He identified the half-lives of the uranium - actinium row and thorium nuclides. He discovered the phenomenon of the electrochemical branching of the radioactive rows. Afterwards Fajans worked on the electrochemical properties of elements as a result of the radioactive changes, and he formulated
1872-461: The law of the radioactive shifts which was later named the radioactive displacement law of Fajans and Soddy ( Frederick Soddy received the Nobel Prize in chemistry in 1921 for his isotopic research). In 1913, together with Oswald Helmuth Göhring , he discovered the first radionuclide of a new element, which was later named protactinium . Fajans and Otto Hahn discovered the formula that defined
1920-629: The most stable being Ac with a half-life of 21.772 years, Ac with a half-life of 10.0 days and Ac with a half-life of 29.37 hours. All remaining radioactive isotopes have half-lives that are less than 10 hours and the majority of them have half-lives shorter than one minute. The shortest-lived known isotope of actinium is Ac (half-life of 69 nanoseconds) which decays through alpha decay . Actinium also has two known meta states . The most significant isotopes for chemistry are Ac, Ac, and Ac. Purified Ac comes into equilibrium with its decay products after about
1968-481: The neutron irradiation of Ra in a nuclear reactor . Owing to its scarcity, high price and radioactivity, actinium has no significant industrial use. Its current applications include a neutron source and an agent for radiation therapy . André-Louis Debierne , a French chemist, announced the discovery of a new element in 1899. He separated it from pitchblende residues left by Marie and Pierre Curie after they had extracted radium . In 1899, Debierne described
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2016-417: The order 50 meters per year). However, evaluation of the concentration depth-profiles for different isotopes allows estimating the mixing rates. The physics behind this method is as follows: oceanic waters contain homogeneously dispersed U. Its decay product, Pa, gradually precipitates to the bottom, so that its concentration first increases with depth and then stays nearly constant. Pa decays to Ac; however,
2064-407: The radiation products, and the selectivity to a certain element is achieved by adjusting the pH (to about 6.0 for actinium). An alternative procedure is anion exchange with an appropriate resin in nitric acid , which can result in a separation factor of 1,000,000 for radium and actinium vs. thorium in a two-stage process. Actinium can then be separated from radium, with a ratio of about 100, using
2112-449: The separation. The first element of the actinides , actinium gave the set its name, much as lanthanum had done for the lanthanides . The actinides are much more diverse than the lanthanides and therefore it was not until 1945 that the most significant change to Dmitri Mendeleev 's periodic table since the recognition of the lanthanides, the introduction of the actinides , was generally accepted after Glenn T. Seaborg 's research on
2160-421: The substance as similar to titanium and (in 1900) as similar to thorium . Friedrich Oskar Giesel found in 1902 a substance similar to lanthanum and called it "emanium" in 1904. After a comparison of the substances' half-lives determined by Debierne, Harriet Brooks in 1904, and Otto Hahn and Otto Sackur in 1905, Debierne's chosen name for the new element was retained because it had seniority, despite
2208-608: The vast majority of historians as the discoverer, lost interest in the element and left the topic. Giesel, on the other hand, can rightfully be credited with the first preparation of radiochemically pure actinium and with the identification of its atomic number 89. The name actinium originates from the Ancient Greek aktis, aktinos (ακτίς, ακτίνος), meaning beam or ray. Its symbol Ac is also used in abbreviations of other compounds that have nothing to do with actinium, such as acetyl , acetate and sometimes acetaldehyde . Actinium
2256-407: Was tested on mice and proved to be effective against leukemia , lymphoma , breast , ovarian , neuroblastoma and prostate cancers . The medium half-life of Ac (21.77 years) makes it a very convenient radioactive isotope in modeling the slow vertical mixing of oceanic waters. The associated processes cannot be studied with the required accuracy by direct measurements of current velocities (of
2304-516: Was that intravenous injection of simple actinium complexes resulted in their accumulation in the bones and liver for a period of tens of years. As a result, after the cancer cells were quickly killed by alpha particles from Ac, the radiation from the actinium and its daughters might induce new mutations. To solve this problem, Ac was bound to a chelating agent, such as citrate , ethylenediaminetetraacetic acid (EDTA) or diethylene triamine pentaacetic acid (DTPA). This reduced actinium accumulation in
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