Saturday, December 20, 2014

Chemistry Concepts Recall A to E

Try you recall these concepts and refresh your subject


Acid, Acid strength, Activity series, Acyllation, Addition reaction, Adsorption, Alkali, Alcohol, Alkali metal, Alkaline earth metal, Aldehyde, Alkane, Alkene, Alkyne, Alkyl radical, Alkenyl radical, Alloy, Allotrope, Aliphatic hydrocarbons, Aliphatic amino acids, Allyl radical, Amalgam, Amides, Amines, Amino acid, Anhydride, Anion, Aromatic compound, Aromaticity, Arenes, Atom, Atomic mass, Atomic number


Base, Base strength, Binary compound, Bond, Bond angle, Bond distance, Bond energy, Bobnd polarity, Bond strength, Boyles' law, Bromination, Bronsted-Lowry's theories, Brownian movement


catalyst, catalitic distillation, cation, chain reaction, charles' law, chemical equilibrium, chemical kinetics, Cis isomer, Colligative property, combustion, concentration, condensation, Configuration isomer, conformation isomer, coordinate covalent bond copolymer, core electrons, covalent compound, Covalent bond, cracking, crystal, crystal shapes, crystallization


Dalton’s law of partial pressures, Deamination, Decane, Decomposition reactions, Delocalised pi bond, Detection of radiation, Differentiating electron, Diffusion of gases, Dipole, Dipole attraction, Displacement reactions, Disproportination, Dissociation coefficients of complex ions, dissolving precipitates, Distillation, Double bond, Double displacement reactions, dsp^3 hybrid orbitals, d^2sp^3 hybrid orbitals


Efflorescence, Photoelectric effect, Einsteinium, Electric charge, Electric potential, Electric current, Electrode potential, Electrolysis, Electrolyte,
Eleectromagentic radiation, Electromotive force (EMF), Electron-dot structure, Electronegativity, Electronic structure, Electron sea theory of metals, Electroplating, Electrovalent bond, Empirical formuala, Emulsion, Endothermic chemical raction, Energy level diagram, Enthalpy, Equilibrium constant, Equilibrium shifts, Equivalence point, Ester, Ether, Europium, Exothermic chemical reaction,

JEE Main - Chapters - Modern Chemistry for Class XI by Dr. S.P. Jauhar

1. Some basic concepts of chemistry


2. States of Matter


3. Atomic Structure


4. Classification of Elements and Periodicity in Properties

5. First Law of Thermodynamics and Chemical Energetics


6. Chemical Bonding and Molecular Structure


7. Equilibrium I – Equilibrium Process and Phase Equilibria


8. Equilibrium II – Ionic Equilibrium in Solutions


9. Redox Reactions


10. Principles and Processes of Extraction of Elements


11. Hydrogen

12. s-Block Elements


13. Some p-Block Elements


14. Organic Chemistry: Some Basic Principles

15. Hydrocarbons

Alkanes - Revision Notes



Aromatics - Benzene

16. Purification and Characterisation of Organic Compounds

17. Organic Compounds with Functional Groups Containing Halogens

Alkyl halides

18. Environmental Pollution

JEE Main - Chapters - Modern Chemistry for Class XII by Dr. S.P. Jauhar

1. Atomic Structure and Chemical Bonding

2. Solid State

3. Solutions

4. Chemical Thermodynamics

5. Electrochemistry

6. Chemical Kinetics

7. Surface Chemistry

8. p-Block Elements

9. d and f -Block Elements

10. Co-ordination Compounds and Organometallics

11. Nuclear Chemistry

A Preview of Organic Chemistry

12. Stereochemistry

13. Organic Compounds with functional Groups Containing Oxygen - I (Alcohols, Phenols and Ethers)

14. Organic Compounds with functional Groups Containing Oxygen – II (Aldehydes, Ketones, Carboxylic Acids and their Derivatives)

15. Organic Compounds with functional Groups Containing Nitrogen (Nitro, Amino, Cyano and Diazo Compounds)

16. Polymers

17. Biomolecules

18. Chemistry in Everyday Life

Chemistry Knowledge History - December

Chemsitry History - December

December 1
The Drunkometer, first practical breath test for alcohol, was patented in 1936 by Rolla Neil Harger (US patent 2,062,785).
Martin Heinrich Klaproth born 1743: discovered uranium (actually uranium dioxide) (U, element 92) from pitchblende; discovered zirconium (Zr, 40); codiscovered cerium (Ce, 58); rediscovered chromium (Cr, 24).
Martin Rodbell born 1925: G-proteins and their role in signaling in cells; Nobel prize (medicine), 1994

December 2

Paul (Ching-Wu) Chu born 1941: high-temperature superconducting materials.

Isabella Karle born (as Isabella Lugoski) 1921: three-dimensional structure of molecules via diffraction of X-rays and electrons.
First artificially initiated self-sustained nuclear fission reaction (Chicago pile one) under Stagg Field, University of Chicago, 1942.
Nikolai Matveyevich Kishner born 1867: Wolff-Kishner reduction of aldehydes and ketones.
Ludwig Knorr born 1859: synthesis of heterocyclic compounds.

December 3

Paul Josef Crutzen born 1933: meteorology and atmospheric chemistry including ozone chemistry; Nobel Prize, 1995. Link to his 1970 paper on nitrogen oxides and ozone.
Carl Koller born 1857: biological effects of cocaine; pioneer in local anaesthesia (with cocaine).
Richard Kuhn born 1900: structure and synthesis of vitamins and carotenoids; refused Nobel Prize in 1938 on instructions of Nazi government, but received it in 1949.
Ellen Swallow Richards born 1842: analytical chemistry, particularly as applied to water quality; founder of the home economics movement
Karl Manne Georg Siegbahn born 1886: X-ray spectroscopy; father of 1981 Nobel laureate electron spectroscopist Kai Siegbahn; Nobel Prize (physics), 1924.

December 4
Alfred Day Hershey born 1908: microbial genetics; Nobel Prize (medicine), 1969.
Charles Holmes Herty born 1867: chemistry of natural resources; paper chemistry.
December 5
Carl Ferdinand Cori born 1896: carbohydrate metabolism; discovered how glycogen is catalytically converted; Nobel Prize (medicine), 1947 (with wife Gerty)
Werner Heisenberg born 1901: quantum mechanics (matrix mechanics); Heisenberg uncertainty principle; Nobel Prize (physics), 1932. See page images of uncertainty principle paper (auf Deutsch).
Christian Friedrich Schönbein received US patent 4,874 for guncotton, 1846.

December 6
Charles Frederick Chandler born 1836: researcher in sugar, petroleum, and illuminating gas industries; a founder of the American Chemical Society
Rudolph Fittig born 1835: organic synthesis (e.g., lactones, toluene); Wurtz-Fittig reaction; discovered diphenyl phenanthrene and coumarone (benzofuran)
Louis-Joseph Gay-Lussac born 1778: law of expansion of gases with increasing temperature; law of combining volumes of gases; isolated boron (B, element 5); research on chlorine, fermentation, prussic acid, and composition of water.
Charles Martin Hall born 1863: discovered method of extracting aluminum electrolytically (US patent 400,665) from bauxite (in his garage)
Nicolas Leblanc born 1742: Leblanc process for making sodium bicarbonate (NaHCO3) from common salt.
George Porter born 1920: developed flash photolysis technique for chemical kinetics; Nobel Prize, 1967
George Eugene Uhlenbeck born 1900: electron spin.

December 7

First thermosetting manmade plastic ("Bakelite") patented, 1909 (US patents 942,699 and 942,700 to Leo Baekeland): reaction involved phenol and formaldehyde.

Linus Pauling published Vitamin C and the Common Cold, 1970.
Theodor Schwann born 1810: named and investigated pepsin; coined the word metabolism.
December 8
Eugene Cook Bingham born 1878: plastic flow and viscosity
Thomas Robert Cech born 1947: discovered cellular role of ribonucleic acid (RNA); Nobel Prize, 1989.
Jan Ingenhousz born 1730: early work on the phenomenon of photosynthesis, including a description of the production of oxygen by plants
Thomas Edward Thorpe born 1845: atomic weights, viscosity of liquids, and chemical analyses

December 9

Claude-Louis Berthollet born 1749: steps toward the law of mass action; analysis of ammonia; discovered bleaching action of chlorine; discovered composition of prussic acid (HCN); showed that acids need not contain oxygen.
Fritz Haber born 1868: high-pressure synthesis of ammonia from hydrogen and nitrogen (Haber process); Nobel Prize, 1918
William Nunn Lipscomb, Jr. born 1919: three-dimensional structure of enzymes and proteins; research on boranes; Nobel Prize, 1976.
Eilhard Mitscherlich read paper on isomorphism to Royal Academy of Science, Berlin, 1819.
Carl Wilhelm Scheele born 1742: discovered chlorine (Cl, element 17); isolated oxygen ("fire air"); Scheele's green; isolated phosphorus (P, element 15) from bone ash; research on action of light on silver salts; synthesized organic acids

December 10

Norbert Rillieux received US Patent 4879 for multiple effect evaporator for sugar refining, 1846.

December 11

Max Born born 1882: quantum mechanics; interpretation of the wave function (Born interpretation); Born-Oppenheimer approximation in molecular quantum mechanics; Nobel Prize (physics), 1954.
Charles Frederick Cross born 1855: rayon manufacture (cellulose acetate), cellulose and papermaking.
Paul Greengard born 1925: biochemical action of dopamine and other neurotransmitters; Nobel Prize (Medicine), 2000.
Vitamin B12 isolated by Merck, Sharp & Dohme Research Laboratories, 1947.
Horace Wells, dentist, first used nitrous oxide as an anesthetic, 1844.

December 12

Eugen Baumann born 1846: iodine in thyroid.
First pure compound of californium (Cf, element 98) announced at 1960 meeting of American Nuclear Society.
William Henry born 1775 : discovered that the solubility of a gas in a liquid is proportional to the gas pressure (Henry's law).
Alfred Werner born 1866: coordination chemistry; inorganic complexes, stereochemistry; Nobel Prize, 1913

December 13

Olaf Kristian Birkeland born 1867: first industrial fixing of nitrogen.
Casein fiber patented, 1938, by Earle Whittier and Stephen Gould.
William Henry Chandler born 1841: academic chemistry laboratory design and instruction in the US.
Charles Alfred Coulson born 1910: Valence and molecular structure calculations.
Johann Wolfgang Döbereiner born 1780: noted triads of elements with similar properties and a progression of atomic weight; catalytic action of platinum; invented instantaneous-lighting lamp (Döbereiner lamp)

Max Josef von Pettenkofer born 1818: calorimeter for human energy changes.

December 14

Max Planck introduced the notion of light as quantized energy packets to the Deutsche Physikalische Gesellschaft, (German Physical Society) 1900.
Glenn Seaborg, Edwin McMillan, Joseph Kennedy, and Arthur Wahl bombarded uranium oxide with 16-MeV deuterons to produce plutonium (Pu, element 94) in 1940.
Edward Lawrie Tatum born 1909: discovered genes which regulate some chemical processes; Nobel Prize (medicine), 1958

December 15
 Antoine-Henri Becqurel born 1852: discovered radioactivity (Becquerel rays) from uranium salts; Nobel Prize (physics), 1903.
Maurice Wilkins born 1916: X-ray crystallography of biological materials; DNA structure; Nobel Prize (medicine), 1962.

December 16
Johann Wilhelm Ritter born 1776: electrolyzed water, collecting hydrogen and oxygen; discovered ultraviolet rays

December 17

Émilie du Châtelet born 1706: chemical nature of fire (Dissertation sur la nature et la propagation du feu); better known for her mathematics and for her relationship with Voltaire.
Humphry Davy born 1778: isolated barium (Ba, element 56), calcium (Ca, 20), magnesium (Mg, 12), potassium (K, 19), sodium (Na, 11), and strontium (Sr, 38); co-discovered boron (B, 5); recognized as elementary and named chlorine (Cl, 17); invented Davy mine safety lamp. His first work on heat and friction includes some insightful ideas and dubious experiments. Read some of his writings on sodium and potassium and on chlorine and its compounds. Read his Researches, Chemical and Philosophical; Chiefly Concerning Nitrous Oxide and his Elements of Chemical Philosophy.
Michael Faraday enunciated first law of electrolysis, "Chemical power, like magnetic force, is in direct proportion to the absolute quantity of electricity which passes," 1832.
Fission of uranium (U, element 92) by neutrons detected by Otto Hahn and Fritz Strassmann in Berlin, 1938; the interpretation of the event as fission would await a paper by Lise Meitner and Otto Frisch.
Willard Frank Libby born 1908: developed carbon dating; Nobel Prize, 1960.
John Lawrence Smith born 1818: toxicology and chemistry of minerals

December 18

Mary Letitia Caldwell born 1890: isolation, structure, and activity of starch enzymes (amylases).

Joseph John (J. J.) Thomson born 1856: characterized "cathode rays", discovering a particle (the electron) with much smaller mass to charge ratio than any known up to that time; Nobel Prize (Physics), 1906. Thomson went on to determine the charge of cathode rays and identify them with other manifestations of electrons; his work on positive rays led to the development of mass spectroscopy; his work on the structure of atoms include his "plum pudding model" and an argument that the number of electrons in an atom was comparable to its atomic mass (in atomic mass units).

Edgar Bright Wilson born 1908: vibrational spectroscopy (Molecular Vibrations ).

December 19

Thomas Andrews born 1813: discovered critical temperatures of gases (temperature above which they cannot be liquefied); read his lecture on the continuity of the gaseous and liquid states.

Berkelium (Bk, element 97) discovered by Kenneth Street, Jr., Stanley G. Thompson, Glenn T. Seaborg, and Albert Ghiorso using ion-exchange chromatography at University of California, Berkeley, 1949.

Pauline Beery Mack born 1891: nutritional content of meat and vegetables; bone density studies; laundering behavior of textiles; Garvan Medal, 1950.

Alan Walsh born 1916: atomic absorption spectroscopy.

December 20

Einsteinium (Es, element 99) discovered by  Louise Smith, Sherman Fried, Gary Higgins; Albert Ghiorso, Rod Spence, Glenn Seaborg, Paul Fields and John Huizenga using ion-exchange chromatography at University of California, Berkeley, 1952.


Thomas Graham 1805: absorption of gases, osmosis, colloids, and dialysis; Graham's law of effusion

Jaroslav Heyrovsky 1890: invented polarographic method of analysis; Nobel Prize, 1959.

December 21

John Mayow baptized 1641 (birth date uncertain): discovered that air contained two gases, one of which ("spiritus nitro-aerous") supported life and combustion.

Hermann Joseph Muller born 1890: theory of genes; mutation by X-rays; Nobel Prize (medicine), 1946.

December 22

William Lloyd Evans born 1870: chemistry of carbohydrates;
Arie Jan Haagen-Smit born 1900: nature and source of smog; smog abatement.
Vladimir Markovnikov born 1838: synthesis of cyclobutane and cyclopentane derivatives; Markovnikov's rule for additions to alkenes.
John Clarke Slater born 1900: orbital approaches to quantum chemistry (Slater-type orbitals, Slater determinant); tetrahedral carbon compounds.

December 23

Axel Fredrik Cronstedt born 1722: discovered nickel (Ni, element 28) and zeolite; classification of minerals
Helen Abbott Michael born 1857: chemical composition of plants; synthetic organic chemistry; author (under the pseudonym Celen Sabbrin), of Science and Philosophy in Art.
Paul Schützenberger born 1829: physiological chemistry.

December 24

James Prescott Joule born 1818: thermodynamics; mechanical equivalent of heat (view his apparatus; Joule-Thomson effect (temperature of gas falls when the gas expands without doing work); kinetic theory of gases
Benjamin Rush born 1745: signer of Declaration of Independence; published first American chemistry textbook
Augustus Vernon-Harcourt born 1834: invented 10-candlepower standard lamp using pentane.

December 25

Herman Frasch born 1851: sulfur mining (Frasch process, developed in Louisiana)
William Gregor born 1761: discovered titanium (Ti, element 22); analysis of minerals
Gerhard Herzberg born 1904: spectroscopic analysis of electronic structure and geometry of molecules and radicals; Nobel Prize, 1971
Isaac Newton born 1642: made fundamental contributions to physics (gravitation, optics, mechanics) and mathematics (calculus); researcher in alchemy.
Ludwig Ferdinand Wilhelmy born 1812: chemical kinetics; first measurement of homogeneous reaction rate.
Adolf Windaus born 1876: synthesis of histamine; structure of cholesterol; research on steroids; Nobel Prize, 1928

December 26

Clemens Winkler born 1838: discovered germanium (Ge, element 32); analysis of gases
Marie and Pierre Curie discover radium (element 88, Ra), 1898.
Ali Javan born 1928: inventor of helium-neon laser, the first gas laser and first continuous-wave (CW) laser.

December 27
Gerardus Johannes Mulder born 1802: protein analysis; physiological chemistry (including chemistry of wine).
Louis Pasteur born 1822: research in stereochemistry (optical activity of tartaric acids), fermentation, decomposition, microbes, and anti-microbial treatment of beverages (pasteurization)

December 28
Ernest Eliel born 1921: organic stereochemistry and conformational analysis
Karl Remigius Fresenius born 1818: qualitative and quantitative analytical chemistry
Kary Mullis born 1944: developed polymerase chain reaction (PCR) for making copies of DNA; Nobel Prize, 1993
Wilhelm Röntgen announced his discovery of new rays, 1895, inspiring research that would lead to a thousand papers on X-rays within a year.
Lewis Hastings Sarett synthesized cortisone at Merck, Sharp & Dohme Research Laboratories, 1944.

December 29

Discovery of heavy water (D2O) announced, 1931.
Ellen Gleditsch born 1879: nuclear chemistry; half life of radium.
Charles Goodyear born 1800: vulcanization of rubber (US patent 3,633)
Helen Vaughn Michel born 1932: neutron activation analysis, with applications to archeology and geology
Alexander Parkes born 1813: invented parkesine (later called xylonite, a kind of celluloid); electroplating

December 30

William David Coolidge of General Electric is issued US Patent 1,082,933 for ductile tungsten for incandescent bulb filaments, 1913.

December 31

Hermann Boerhaave born 1668: physician and chemist, Elementa Chemiae
Joseph Louis Gay-Lussac read his memoir on combining volumes of gases to the Philomathic Society of Arcueil, 1808.
Colin Garfield Fink born 1881: electrochemical research, development, industry, and education; president of the Electrochemical Society
Gilbert Stork born 1921: organic synthesis; first stereorational synthesis (cantharidin, 1951); stereoselective total synthesis of quinine.

Science History  in December

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Einsteinium - Element - Atomic Number 99

Einsteinium was first identified in December 1952 by Albert Ghiorso and co-workers at the University of California, Berkeley in collaboration with the Argonne and Los Alamos National Laboratories, in the fallout from the Ivy Mike nuclear test.

Ghiorso and co-workers analyzed filter papers which had been flown through the explosion cloud on airplanes (the same sampling technique that had been used to discover 244
94Pu). Larger amounts of radioactive material were later isolated from coral debris of the atoll, which 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 the end.

Nevertheless, element 99 (einsteinium), namely its 253Es isotope, 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.

Later, 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 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.

In their discovery of the 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, the Swedish group succeeded in the synthesis of light isotopes of element 100, in particular 250Fm, 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 the Berkeley team was given the privilege to name the new elements. The official names suggested by the Berkeley group derived from two prominent scientists, Albert Einstein and Enrico Fermi:  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 is a synthetic, silvery-white, 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/cm3 is lower than that of californium (15.1 g/cm3) and is nearly the same as that of holmium (8.79 g/cm3), despite atomic einsteinium being much heavier than holmium. The melting point of einsteinium (860 °C) is also relatively low – below californium (900 °C), fermium (1527 °C) and holmium (1461 °C). Einsteinium is a soft metal, with the bulk modulus of only 15 GPa, which value is one of the lowest among non-alkali metals.

The metal is divalent and has a noticeably high volatility.

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 µB for Es2O3 and 11.4 ± 0.3 µB for the EsF3, 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 induced pale pink color. The existence of divalent einsteinium is firmly established, especially in 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. The oxidation state +4 was postulated from vapor studies and is yet uncertain.

Nineteen nuclides and three nuclear isomers are known for einsteinium with atomic weights ranging from 240 to 258. All are radioactive and the most stable nuclide, 252Es, has a half-life of 471.7 days.[ Next most stable isotopes are 254Es (half-life 275.7 days), 255Es (39.8 days) and 253Es (20.47 days). All of the remaining isotopes have half-lives shorter than 40 hours, and most of them decay within less than 30 minutes. Of the three nuclear isomers, the most stable is 254mEs with half-life of 39.3 hours.

Synthesis and extraction

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 the Oak Ridge National Laboratory in Tennessee, U.S., and 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, although the quantities produced at NIIAR are not widely reported. In a "typical processing campaign" at Oak Ridge, tens of grams of curium are irradiated to produce decigram quantities of californium, milligram quantities of berkelium (249Bk) and einsteinium and picogram quantities of fermium.

The first microscopic sample of 253Es sample weighing about 10 nanograms was prepared in 1961 at HFIR.  Larger batches were produced later starting from several kilograms of plutonium with the einsteinium yields (mostly 253Es) of 0.48 milligrams 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 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: 253Es (α-emitter with half-life of 20.03 days and with a spontaneous fission half-life of 7×105 years); 254mEs (β-emitter with half-life of 38.5 hours), 254Es (α-emitter with half-life of about 276 days) and 255Es (β-emitter with half-life of 24 days). An alternative route involves bombardment of uranium-238 with high-intensity nitrogen or oxygen ion beams.

Einsteinium-247 (half-life 4.55 minutes) was produced by irradiating americium-241 with carbon or uranium-238 with nitrogen ions. The latter reaction was first realized in 1967 in Dubna, Russia, and the involved scientists were awarded the Lenin Komsomol Prize.

The isotope 248Es was produced by irradiating 249Cf with deuterium ions. It mainly decays by emission of electrons to 248Cf with a half-life of 25 (±5) minutes, but also releases α-particles of 6.87 MeV energy, with the ratio of electrons to α-particles of about 400.

The heavier isotopes 249Es, 250Es, 251Es and 252Es were obtained by bombarding 249Bk with α-particles. One to four neutrons are liberated in this process making possible the formation of four different isotopes in one reaction.

Einsteinium-253 was produced by irradiating a 0.1–0.2 milligram 252Cf target with a thermal neutron flux of (2–5)×1014 neutrons·cm−2·s−1 for 500–900 hours:[64]

A personal account by Ghiorso