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About Einsteinium

Einsteinium Bohr

Einsteinium, a transuranic actinide, is one of many elements to be identified by a team led by Albert Ghiorso. It was discovered among debris that was swept up with the fallout from Ivy Mike, the first successful hydrogen bomb test, in 1952. Due to the Cold War, its discovery was kept secret until 1955. The name einsteinium was chosen to honor Albert Einstein. Today, the most common isotope of the element, einsteinium-253, is synthesized in a few dedicated high power nuclear reactors from the decay of californium-253, while other isotopes are produced in small amounts by bombarding heavy actinides with light ions. The most stable isotope of the element, einsteinium-252, has proven difficult to produce in significant quantities, which has hampered study of einsteinium's physical properties, though it is know to be a soft, silvery, paramagnetic metal. The high radioactivity of einsteinium-253 produces a visible glow.

As the most easily produced isotope of einsteinium is very unstable, commercial uses for the element have not been developed. Einsteinium is therefore used exclusively in research contexts, primarily in the production of other transuranium elements. Notably, the element mendelevium was first synthesized using einsteinium.

Einsteinium Properties

Einsteinium Bohr ModelEinsteinium is a Block F, Group 3, Period 7 element. The number of electrons in each of einsteinium's shells is 2, 8, 18, 32, 29, 8, 2 and its electronic configuration is [Rn] 5f11 7s2. The einsteinium atom has a radius of 186.pm. In its elemental form, einsteinium's CAS number is 7429-92-7. Einsteinium was discovered at the Lawrence Berkeley Natinal Laboratory in 1952 and named in honor of Albert Einstein. Einsteinium was the seventh transuranic element of the actinide series to be discovered.

Einsteinium information, including technical data, safety data and its properties, research, applications and other useful facts are discussed below. Scientific facts such as the atomic structure, ionization energy, abundance on Earth, conductivity and thermal properties are included.

Symbol: Es
Atomic Number: 99
Atomic Weight: 252
Element Category: Actinide
Group, Period, Block: n/a, 7, f
Color: unknown (presumably metallic/ silvery white/ gray)
Other Names: Einstenio, Einstânio
Melting Point: 860 °C, 1580 °F, 1133.15 K
Boiling Point: N/A
Density: 8.84 g/cm3
Liquid Density @ Melting Point: N/A
Density @ 20°C: 8.84 g/cm3
Density of Solid: 13500 kg·m3
Specific Heat: N/A
Superconductivity Temperature: N/A
Triple Point: N/A
Critical Point: N/A
Heat of Fusion (kJ·mol-1): N/A
Heat of Vaporization (kJ·mol-1): N/A
Heat of Atomization (kJ·mol-1): 150
Thermal Conductivity: N/A
Thermal Expansion: N/A
Electrical Resistivity: N/A
Tensile Strength: N/A
Molar Heat Capacity: N/A
Young's Modulus: N/A
Shear Modulus: N/A
Bulk Modulus: N/A
Poisson Ratio: N/A
Mohs Hardness: N/A
Vickers Hardness: N/A
Brinell Hardness: N/A
Speed of Sound: N/A
Pauling Electronegativity: 1.3
Sanderson Electronegativity: N/A
Allred Rochow Electronegativity: 1.2
Mulliken-Jaffe Electronegativity: N/A
Allen Electronegativity: N/A
Pauling Electropositivity: 2.7
Reflectivity (%): N/A
Refractive Index: N/A
Electrons: 99
Protons: 99
Neutrons: 153
Electron Configuration: [Rn] 5f11 7s2
Atomic Radius: pm (estimated)
Atomic Radius,
non-bonded (Å):
2.45
Covalent Radius: pm (estimated)
Covalent Radius (Å): 1.65
Van der Waals Radius: N/A
Oxidation States: 2, 3, 4
Phase: Solid
Crystal Structure: face-centered cubic
Magnetic Ordering: paramagnetic
Electron Affinity (kJ·mol-1) Unknown
1st Ionization Energy: 619 kJ·mol-1 (estimated)
2nd Ionization Energy: N/A
3rd Ionization Energy: N/A
CAS Number: 7429-92-7
EC Number: N/A
MDL Number: N/A
Beilstein Number: N/A
SMILES Identifier: [Es]
InChI Identifier: InChI=1S/Es
InChI Key: CKBRQZNRCSJHFT-UHFFFAOYSA-N
PubChem CID: 23913
ChemSpider ID: 22356
Earth - Total: N/A
Mercury - Total: N/A
Venus - Total: N/A
Earth - Seawater (Oceans), ppb by weight: N/A
Earth - Seawater (Oceans), ppb by atoms: N/A
Earth -  Crust (Crustal Rocks), ppb by weight: N/A
Earth -  Crust (Crustal Rocks), ppb by atoms: N/A
Sun - Total, ppb by weight: N/A
Sun - Total, ppb by atoms: N/A
Stream, ppb by weight: N/A
Stream, ppb by atoms: N/A
Meterorite (Carbonaceous), ppb by weight: N/A
Meterorite (Carbonaceous), ppb by atoms: N/A
Typical Human Body, ppb by weight: N/A
Typical Human Body, ppb by atom: N/A
Universe, ppb by weight: N/A
Universe, ppb by atom: N/A
Discovered By: Lawrence Berkeley Nat'l Laboratory
Discovery Date: 1952
First Isolation: N/A

Einsteinium Isotopes

Einsteinium is an artificial element. It has no stable isotopes.

Nuclide Isotopic Mass Half-Life Mode of Decay Nuclear Spin Magnetic Moment Binding Energy (MeV) Natural Abundance
(% by atom)
240Es 240.06892(43)# 1# s α to 236Bk N/A N/A 1795.465942 -
241Es 241.06854(24)# 10(5) s α to 237Bk (3/2-) N/A 1803.776978 -
242Es 242.06975(35)# 13.5(25) s α to 238Bk; SF N/A N/A 1810.883057 -
243Es 243.06955(25)# 21(2) s β+ to 244Cf; α to 240Bk; SF 3/2-# N/A 1819.017944 -
244Es 244.07088(20)# 37(4) s β+ to 243Cf; α to 239Bk N/A N/A 1825.843018 -
245Es 245.07132(22)# 1.1(1) min β+ to 244Cf; α to 240Bk (3/2-) N/A 1833.588989 -
246Es 246.07290(24)# 7.7(5) min β+ to 245Cf; α to 241Bk; SF 4-# N/A 1840.125977 -
247Es 247.07366(3)# 4.55(26) min β+ to 246Cf; α to 242Bk; SF 7/2+# N/A 1847.560059 -
248Es 248.07547(6)# 27(5) min β+ to 247Cf; α to 243Bk; SF 2-#,0+# N/A 1853.946045 -
249Es 249.07641(3)# 102.2(6) min EC to 249Cf; α to 245Bk 7/2+ N/A 1861.135986 -
250Es 250.07861(11)# 8.6(1) h EC to 250Cf; α to 246Bk (6+) N/A 1867.112061 -
251Es 251.079992(7) 33(1) h EC to 251Cf; α to 247Bk (3/2-) N/A 1873.944824 -
252Es 252.08298(5) 471.7(19) d EC to 252Cf; α to 248Bk; β- to 252Fm (5-) N/A 1879.232178 -
253Es 253.0848247(28) 20.47(3) d α to 249Bk; SF 7/2+ 4.1 1885.584229 -
254Es 254.088022(5) 275.7(5) d EC to SFCf; α to 250Bk; β- to 254Fm (7+) N/A 1890.676636 -
255Es 255.090273(12) 39.8(12) d β- to 256Fm (7/2+) N/A 1896.651733 -
256Es 256.09360(11)# 25.4(24) min α to 251Bk; β- to 255Fm; SF (1+,0-) N/A 1901.625977 -
257Es 257.09598(44)# 7.7(2) d β- to 257Fm; α to 253Bk 7/2+# N/A 1907.473999 -
258Es 258.09952(32)# 3# min Unknown N/A N/A N/A -
Einsteinium Elemental Symbol

Recent Research & Development for Einsteinium

  • Chemical consequences of radioactive decay: Spectrophotometric study of the ingrowth of berkelium-249 and californium-249 into halides of einsteinium-253. J. P. Young, R. G. Haire, J. R. Peterson, D. D. Ensor, R. L. Fellow. Inorg. Chem.
  • J.R. Peterson, N. Erdmann, M. Nunnemann, K. Eberhardt, G. Huber, J.V. Kratz, G. Passler, O. Stetzer, P. Thörle, N. Trautmann, A. Waldek, Determination of the first ionization potential of einsteinium by resonance ionization mass spectroscopy (RIMS), Journal of Alloys and Compounds, Volumes 271–273, 12 June 1998
  • S.A. Kulyukhin, L.N. Auerman, V.L. Novichenko, N.B. Mikheev, I.A. Rumer, A.N. Kamenskaya, L.A. Goncharov, A.I. Smirnov, Production of microgram quantities of einsteinium-253 by the reactor irradiation of californium, Inorganica Chimica Acta, Volume 110, Issue 1, July 1985
  • Joel F. Liebman, Conceptual problems in noble gas and fluorine chemistry, VII1: On the possible existence of einsteinium and proactinium hexafluoride, Inorganic and Nuclear Chemistry Letters, Volume 14, Issues 6–7, 1978
  • Irshad Ahmad, Frank Wagner Jr., Half-life of the longest-lived einsteinium isotope-252Es, Journal of Inorganic and Nuclear Chemistry, Volume 39, Issue 9, 1977
  • R.L. Fellows, J.R. Peterson, M. Noé, J.P. Young, R.G. Haire, X-ray diffraction and spectroscopic studies of crystalline einsteinium(III) bromide, 253EsBr3, Inorganic and Nuclear Chemistry Letters, Volume 11, Issue 11, November 1975