Einsteinium compounds

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Einsteinium compounds are compounds that contain the element einsteinium (Es). These compounds largely have einsteinium in the +3 oxidation state, or in some cases in the +2 and +4 oxidation states. Although einsteinium is relatively stable, with half-lives ranging from 20 days upwards, these compounds have not been studied in great detail.

Contents

Properties of einsteinium compounds

Crystal structure and lattice constants of some Es compounds
CompoundColorSymmetry Space group No Pearson symbol Lattice constants
(pm)
abc
Es2O3 ColorlessCubic [1] Ia3206cI801076.6
Es2O3 Colorless Monoclinic [2] C2/m12mS301411359880
Es2O3 ColorlessHexagonal [2] P3m1164hP5370600
EsF3 Hexagonal [3]
EsF4 Monoclinic [4] C2/c15mS60
EsCl3 OrangeHexagonal [5] [6] C63/mhP8727410
EsBr3 YellowMonoclinic [7] C2/m12mS167271259681
EsI3 AmberHexagonal [8] [9] R3148hR247532084
EsOCl Tetragonal [8] [10] P4/nmm394.8670.2

Oxides

Einsteinium(III) oxide (Es2O3) was obtained by burning einsteinium(III) nitrate. It forms colorless cubic crystals, which were first characterized from microgram samples sized about 30 nanometers. [11] [1] Two other phases, monoclinic and hexagonal, are known for this oxide. The formation of a certain Es2O3 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. [12] The hexagonal phase is isotypic with lanthanum oxide where the Es3+ ion is surrounded by a 6-coordinated group of O2− ions. [2] [8]

Halides

Einsteinium(III) iodide glowing in the dark Einsteinium triiodide by transmitted light.jpg
Einsteinium(III) iodide glowing in the dark

Einsteinium halides are known for the oxidation states +2 and +3. [10] [13] The most stable state is +3 for all halides from fluoride to iodide.

Einsteinium(III) fluoride (EsF3) can be precipitated from einsteinium(III) chloride solutions upon reaction with fluoride ions. An alternative preparation procedure is to exposure einsteinium(III) oxide to chlorine trifluoride (ClF3) or F2 gas at a pressure of 1–2 atmospheres and a temperature between 300 and 400 °C. The EsF3 crystal structure is hexagonal, as in californium(III) fluoride (CfF3) where the Es3+ ions are 8-fold coordinated by fluorine ions in a bicapped trigonal prism arrangement. [3] [14] [15]

Einsteinium(III) chloride (EsCl3) can be prepared by annealing einsteinium(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 UCl3 type, where einsteinium atoms are 9-fold coordinated by chlorine atoms in a tricapped trigonal prism geometry. [6] [14] [16] Einsteinium(III) bromide (EsBr3) is a pale-yellow solid with a monoclinic structure of AlCl3 type, where the einsteinium atoms are octahedrally coordinated by bromine (coordination number 6). [9] [14]

The divalent compounds of einsteinium are obtained by reducing the trivalent halides with hydrogen: [17]

2 EsX3 + H2 → 2 EsX2 + 2 HX,    X = F, Cl, Br, I

Einsteinium(II) chloride (EsCl2), [18] einsteinium(II) bromide (EsBr2), [19] and einsteinium(II) iodide (EsI2) [10] have been produced and characterized by optical absorption, with no structural information available yet. [9]

Known oxyhalides of einsteinium include EsOCl, [10] EsOBr [17] and EsOI. [10] These salts are synthesized by treating a trihalide with a vapor mixture of water and the corresponding hydrogen halide: for example, EsCl3 + H2O/HCl to obtain EsOCl. [20]

Organoeinsteinium compounds

The high radioactivity of einsteinium has a potential use in radiation therapy, and organometallic complexes have been synthesized in order to deliver einsteinium atoms to an appropriate organ in the body. Experiments have been performed on injecting einsteinium citrate (as well as fermium compounds) to dogs. [21] Einsteinium(III) was also incorporated into beta-diketone chelate complexes, since analogous complexes with lanthanides previously showed strongest UV-excited luminescence among metallorganic compounds. When preparing einsteinium complexes, the Es3+ ions were 1000 times diluted with Gd3+ ions. This allowed reducing the radiation damage so that the compounds did not disintegrate during the period of 20 minutes required for the measurements. The resulting luminescence from Es3+ 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 Es3+ ions. Similar conclusion was drawn for other actinides americium, berkelium and fermium. [22]

Luminescence of Es3+ ions was however observed in inorganic hydrochloric acid solutions as well as in organic solution with di(2-ethylhexyl)orthophosphoric acid. It shows a broad peak at about 1064 nanometres (half-width about 100 nm) which can be resonantly excited by green light (ca. 495 nm wavelength). The luminescence has a lifetime of several microseconds and the quantum yield below 0.1%. The relatively high, compared to lanthanides, non-radiative decay rates in Es3+ were associated with the stronger interaction of f-electrons with the inner Es3+ electrons. [23]

See also

Related Research Articles

The actinide or actinoid series encompasses the 14 metallic chemical elements with atomic numbers from 89 to 103, actinium through Lawrencium. The actinide series derives its name from the first element in the series, actinium. The informal chemical symbol An is used in general discussions of actinide chemistry to refer to any actinide.

<span class="mw-page-title-main">Berkelium</span> Chemical element, symbol Bk and atomic number 97

Berkelium is a synthetic chemical element; it has symbol Bk and atomic number 97. It is a member of the actinide and transuranium element series. It is named after the city of Berkeley, California, the location of the Lawrence Berkeley National Laboratory where it was discovered in December 1949. Berkelium was the fifth transuranium element discovered after neptunium, plutonium, curium and americium.

<span class="mw-page-title-main">Curium</span> Chemical element, symbol Cm and atomic number 96

Curium is a synthetic chemical element; it has symbol Cm and atomic number 96. This transuranic actinide element was named after eminent scientists Marie and Pierre Curie, both known for their research on radioactivity. Curium was first intentionally made by the team of Glenn T. Seaborg, Ralph A. James, and Albert Ghiorso in 1944, using the cyclotron at Berkeley. They bombarded the newly discovered element plutonium with alpha particles. This was then sent to the Metallurgical Laboratory at University of Chicago where a tiny sample of curium was eventually separated and identified. The discovery was kept secret until after the end of World War II. The news was released to the public in November 1947. Most curium is produced by bombarding uranium or plutonium with neutrons in nuclear reactors – one tonne of spent nuclear fuel contains ~20 grams of curium.

<span class="mw-page-title-main">Californium</span> Chemical element, symbol Cf and atomic number 98

Californium is a synthetic chemical element; it has symbol Cf and atomic number 98. The element was first synthesized in 1950 at Lawrence Berkeley National Laboratory, by bombarding curium with alpha particles. It is an actinide element, the sixth transuranium element to be synthesized, and has the second-highest atomic mass of all elements that have been produced in amounts large enough to see with the naked eye. The element was named after the university and the U.S. state of California.

<span class="mw-page-title-main">Einsteinium</span> Chemical element, symbol Es and atomic number 99

Einsteinium is a synthetic chemical element; it has symbol Es and atomic number 99. Einsteinium is a member of the actinide series and it is the seventh transuranium element. It was named in honor of Albert Einstein.

<span class="mw-page-title-main">Californium compounds</span>

Few compounds of californium have been made and studied. The only californium ion that is stable in aqueous solutions is the californium(III) cation. The other two oxidation states are IV (strong oxidizing agents) and II (strong reducing agents). The element forms a water-soluble chloride, nitrate, perchlorate, and sulfate and is precipitated as a fluoride, oxalate or hydroxide. If problems of availability of the element could be overcome, then CfBr2 and CfI2 would likely be stable.

<span class="mw-page-title-main">Berkelium compounds</span> Any chemical compound having at least one berkelium atom

Berkelium forms a number of chemical compounds, where it normally exists in an oxidation state of +3 or +4, and behaves similarly to its lanthanide analogue, terbium. Like all actinides, berkelium easily dissolves in various aqueous inorganic acids, liberating gaseous hydrogen and converting into the trivalent oxidation state. This trivalent state is the most stable, especially in aqueous solutions, but tetravalent berkelium compounds are also known. The existence of divalent berkelium salts is uncertain and has only been reported in mixed lanthanum chloride-strontium chloride melts. Aqueous solutions of Bk3+ ions are green in most acids. The color of the Bk4+ ions is yellow in hydrochloric acid and orange-yellow in sulfuric acid. Berkelium does not react rapidly with oxygen at room temperature, possibly due to the formation of a protective oxide surface layer; however, it reacts with molten metals, hydrogen, halogens, chalcogens and pnictogens to form various binary compounds. Berkelium can also form several organometallic compounds.

<span class="mw-page-title-main">Einsteinium(III) oxide</span> Chemical compound

Einsteinium(III) oxide is an oxide of the synthetic actinide einsteinium which has the molecular formula Es2O3. It is a colourless solid.

<span class="mw-page-title-main">Curium(III) fluoride</span> Chemical compound

Curium(III) fluoride or curium trifluoride is the chemical compound composed of curium and fluorine with the formula CmF3. It is a white, nearly insoluble salt that has the same crystal structure as LaF3. It precipitates as a hydrate when fluoride ions are added to a weakly acidic Cm(III) solution; alternatively it can be synthesized by reacting hydrofluoric acid with Cm(OH)3. The anhydrous form is then obtained by desiccation or by treatment with hydrogen fluoride gas.

Californium(III) chloride is an inorganic compound with a chemical formula CfCl3. Like in californium oxide (Cf2O3) and other californium halides, including californium fluoride (CfF3) and iodide (CfI3), the californium atom has an oxidation state of +3.

<span class="mw-page-title-main">Californium(III) bromide</span> Chemical compound

Californium(III) bromide is an inorganic compound, a salt with a chemical formula CfBr3. Like in californium oxide (Cf2O3) and other californium halides, including californium(III) fluoride (CfF3), californium(III) chloride, and californium(III) iodide (CfI3), the californium atom has an oxidation state of +3.

<span class="mw-page-title-main">Berkelium(IV) oxide</span> Chemical compound

Berkelium(IV) oxide, also known as berkelium dioxide, is a chemical compound with the formula BkO2. This compound slowly decays to californium(IV) oxide. It can be converted to berkelium(III) oxide by hydrogen reduction at 600 °C.

Curium compounds are compounds containing the element curium (Cm). Curium usually forms compounds in the +3 oxidation state, although compounds with curium in the +4, +5 and +6 oxidation states are also known.

<span class="mw-page-title-main">Berkelium(III) nitrate</span> Chemical compound

Berkelium(III) nitrate is the berkelium salt of nitric acid with the formula Bk(NO3)3. It commonly forms the tetrahydrate, Bk(NO3)3·4H2O, which is a light green solid. If heated to 450 °C, it decomposes to berkelium(IV) oxide and 22 milligrams of the solution of this compound is reported to cost one million dollars.

<span class="mw-page-title-main">Berkelium(III) chloride</span> Chemical compound

Berkelium(III) chloride also known as berkelium trichloride, is a chemical compound with the formula BkCl3. It is a water-soluble green salt with a melting point of 603 °C. This compound forms the hexahydrate, BkCl3·6H2O.

Protactinium compounds are compounds containing the element protactinium. These compounds usually have protactinium in the +5 oxidation state, although these compounds can also exist in the +2, +3 and +4 oxidation states.

Americium compounds are compounds containing the element americium (Am). These compounds can form in the +2, +3, and +4, although the +3 oxidation state is the most common. The +5, +6 and +7 oxidation states have also been reported.

<span class="mw-page-title-main">Berkelium(III) fluoride</span> Chemical compound

Berkelium(III) fluoride is a binary inorganic compound of berkelium and fluorine with the chemical formula BkF
3.

<span class="mw-page-title-main">Berkelium(III) bromide</span> Chemical compound

Berkelium bromide is a bromide of berkelium, with the chemical formula BkBr3.

Einsteinium fluoride is a binary inorganic chemical compound of einsteinium and fluorine with the chemical formula EsF3.

References

  1. 1 2 Haire, R. G.; Baybarz, R. D. (1973). "Identification and analysis of einsteinium sesquioxide by electron diffraction". Journal of Inorganic and Nuclear Chemistry. 35 (2): 489–496. doi:10.1016/0022-1902(73)80561-5.
  2. 1 2 3 Haire, R. G. & Eyring, L. (1994). "Lanthanides and Actinides Chemistry". In K.A. Gscheidner, Jr.; et al. (eds.). Handbook on the Physics and Chemistry of Rare Earths. Vol. 18. North-Holland, New York. pp. 414–505. ISBN   978-0-444-81724-2.{{cite book}}: CS1 maint: location missing publisher (link)
  3. 1 2 Ensor, D. D.; Peterson, J. R.; Haire, R. G.; Young, J. P. (1981). "Absorption spectrophotometric study of 253EsF3 and its decay products in the bulk-phase solid state". Journal of Inorganic and Nuclear Chemistry. 43 (10): 2425–2427. doi:10.1016/0022-1902(81)80274-6.
  4. ↑ Kleinschmidt, P. (1994). "Thermochemistry of the actinides". Journal of Alloys and Compounds. 213–214: 169–172. doi:10.1016/0925-8388(94)90898-2. Archived from the original on 2020-03-16. Retrieved 2019-07-14.
  5. ↑ Fujita, D.; Cunningham, B. B.; Parsons, T. C. (1969). "Crystal structures and lattice parameters of einsteinium trichloride and einsteinium oxychloride". Inorganic and Nuclear Chemistry Letters. 5 (4): 307–313. doi:10.1016/0020-1650(69)80203-5. Archived from the original on 2020-03-13. Retrieved 2019-07-14.
  6. 1 2 Miasoedov, B. F. Analytical chemistry of transplutonium elements, Wiley, 1974 (Original from the University of California), ISBN   0-470-62715-8, p. 99
  7. ↑ Fellows, R.; Peterson, J. R.; Noé, M.; Young, J. P.; Haire, R. G. (1975). "X-ray diffraction and spectroscopic studies of crystalline einsteinium(III) bromide, 253EsBr3". Inorganic and Nuclear Chemistry Letters. 11 (11): 737–742. doi:10.1016/0020-1650(75)80090-0.
  8. 1 2 3 Haire, pp. 1595–1596
  9. 1 2 3 Seaborg, p. 62
  10. 1 2 3 4 5 Young, J. P.; Haire, R. G.; Peterson, J. R.; Ensor, D. D.; Fellow, R. L. (1981). "Chemical consequences of radioactive decay. 2. Spectrophotometric study of the ingrowth of berkelium-249 and californium-249 into halides of einsteinium-253". Inorganic Chemistry. 20 (11): 3979–3983. doi:10.1021/ic50225a076.
  11. ↑ Greenwood, p. 1268
  12. ↑ Haire, p. 1598
  13. ↑ Holleman, p. 1969
  14. 1 2 3 Greenwood, p. 1270
  15. ↑ Young, J. P.; Haire, R. G.; Fellows, R. L.; Peterson, J. R. (1978). "Spectrophotometric studies of transcurium element halides and oxyhalides in the solid state". Journal of Radioanalytical Chemistry. 43 (2): 479–488. doi:10.1007/BF02519508. S2CID   95361392.
  16. ↑ Fujita, D.; Cunningham, B. B.; Parsons, T. C.; Peterson, J. R. (1969). "The solution absorption spectrum of Es3+". Inorganic and Nuclear Chemistry Letters. 5 (4): 245–250. doi:10.1016/0020-1650(69)80192-3. Archived from the original on 2020-03-09. Retrieved 2019-07-14.
  17. 1 2 Peterson, J.R.; et al. (1979). "Preparation, characterization, and decay of einsteinium(II) in the solid state" (PDF). Le Journal de Physique. 40 (4): C4–111. CiteSeerX   10.1.1.729.8671 . doi:10.1051/jphyscol:1979435. S2CID   95575017. Archived (PDF) from the original on 2012-03-07. Retrieved 2010-11-24. manuscript draft Archived 2013-05-13 at the Wayback Machine
  18. ↑ Fellows, R.L.; Young, J.P.; Haire, R.G. and Peterson J.R. (1977) in: GJ McCarthy and JJ Rhyne (eds) The Rare Earths in Modern Science and Technology, Plenum Press, New York, pp. 493–499.
  19. ↑ Young, J.P.; Haire R.G., Fellows, R.L.; Noe, M. and Peterson, J.R. (1976) "Spectroscopic and X-Ray Diffraction Studies of the Bromides of Californium-249 and Einsteinium-253", in: W. Müller and R. Lindner (eds.) Plutonium 1975, North Holland, Amsterdam, pp. 227–234.
  20. ↑ Seaborg, p. 60
  21. ↑ Haire, p. 1579
  22. ↑ Nugent, Leonard J.; Burnett, J. L.; Baybarz, R. D.; Werner, George Knoll; Tanner, S. P.; Tarrant, J. R.; Keller, O. L. (1969). "Intramolecular energy transfer and sensitized luminescence in actinide(III) .beta.-diketone chelates". The Journal of Physical Chemistry. 73 (5): 1540–1549. doi:10.1021/j100725a060.
  23. ↑ Beitz, J.; Wester, D.; Williams, C. (1983). "5f state interaction with inner coordination sphere ligands: Es3+ ion fluorescence in aqueous and organic phases". Journal of the Less Common Metals. 93 (2): 331–338. doi:10.1016/0022-5088(83)90178-9.
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