Einsteinium
einsteinium atom
Identifiers & Physical Properties
| CAS No. | 7429-92-7 |
|---|---|
| Molecular formula | Es |
| Average molar mass | 252.083 g/mol |
| Monoisotopic mass | 252.083 g/mol |
| SMILES | [Es] |
| InChIKey | CKBRQZNRCSJHFT-UHFFFAOYSA-N |
| PubChem CID | 23913 |
| ChEBI | CHEBI:33393 |
| DTXSID | DTXSID30225305 |
Chemical & Physical Properties
| Topological polar surface area | 0 |
|---|---|
| Hydrogen bond donors | 0 |
| Hydrogen bond acceptors | 0 |
| Rotatable bonds | 0 |
| Heavy atoms | 1 |
| Formal charge | 0 |
| Complexity | 0 |
| Chemical classes | Physical/Radiation -> Radionuclides |
| SpringerMaterials Properties | nuclear state |
| Physical Description | A metal with a melting point of about 860 degrees C[Merck Index] |
| Melting point | 860 ±50° |
| Density | 8.84 |
| Physical state | metal |
| Color | metalcubic |
| Bulk Modulus | 15.0 GPa, Estimated |
| CAS DataBase Reference | 7429-92-7 |
| FDA UNII | WV8XL34X3O |
Safety & Regulations
| Hazards summary | Most Important Radionuclide: Es-254 Source: Neutron bombardment of plutoniumHalf-Life: 472 days Lung Clearance Half-Time: Weeks Internal Toxicity: Very High Annual Limit on Intake: 0.00002 mCi[See Glossary for references.] See Radiation, ionizing. |
|---|
Applications & Uses
General Description
The first isotope of this element having mass number 253 and half-life 20 days was detected in 1952 in the Pacific in debris from the first thermonuclear explosion. The isotope was an alpha emitter of 6.6 MeV energy, chemically analogous to the rare earth element holmium. Isotope 246, having a half-life 7.3 minutes, was synthesized in the Lawrence Berkeley Laboratory cyclotron in 1954. The element was named Einsteinium in honor of Albert Einstein. Only microgram amounts have been synthesized. The element has high specific alpha activities. It may be used as a tracer in chemical studies. Commercial applications are few.
History
The name of Es derives from “Albert Einstein”, the Geituan born physicist who proposed the theory of relativity. A collaboration of American scientists G. R. Choppin, S. G. Thompson, A. Ghiorso, and B. G. Harvey, from the Argonne National Laboratory near Chicago, Illinois, the Los Alamos Scientific Laboratory in Los Alamos, New Mexico and at the University of California lab in Berkeley, CA, first found 252Es in the radioactive debris from the first large thermonuclear bomb explosion, nicknamed “Mike,” which took place at Enewetak atoll, Marshall Islands in the Pacific on November 1, 1952. The longest halflife associated with this unstable element is 472 day 252Es.