Einstein - transuranic chemical element with atomic number 99, radioactive silver metal .
| Einsteinium | |||
|---|---|---|---|
| ← California | Fermium → | |||
| |||
| The appearance of a simple substance | |||
| Radioactive Silver Metal | |||
 | |||
| Atom properties | |||
| Name, symbol, number | Einsteinium (Es), 99 | ||
| Atomic mass ( molar mass ) | 252,083 a. E. m. ( g / mol ) | ||
| Electronic configuration | [Rn] 5f 11 7s 2 | ||
| Atom radius | 292 pm | ||
| Chemical properties | |||
| Electronegativity | 1.3 (Pauling scale) | ||
| Electrode potential | Es ← Es 3+ −2.0 V Es ← Es 2+ −2.2 V | ||
| Oxidation state | 2, 3 , 4 | ||
| Ionization energy (first electron) | 619 kJ / mol ( eV ) | ||
| Thermodynamic properties of a simple substance | |||
| Density (at N. at. ) | 13.5 g / cm³ | ||
| Melting temperature | 860 ° C | ||
| CAS Number | |||
| 99 | Einsteinium |
Es (252) | |
| 5f 11 7s 2 | |
Content
History
Einstein was discovered in December 1952 . The element is named after Albert Einstein .
Physical and chemical properties
Einstein is a radioactive metal . Belongs to the actinoid family.
In compounds, Einsteinium exhibits oxidation states of +2 and +3. An example is its iodide with the chemical formula EsI 3 . In a normal aqueous solution, Einsteinium exists in the most stable form in the form of Es 3+ ions (gives a green color ).
Einsteinium is a metal with a cubic face-centered lattice , the lattice parameter a = 0.575 nm , and the melting temperature is 860 ° C. It is characterized by relatively high volatility and can be obtained by reducing EsF 3 with lithium . Many Einsteinium solid compounds have been synthesized and studied, such as Es 2 O 3 , EsCl 3 , EsOCl, EsBr 2 , EsBr 3 , EsI 2 and EsI 3 .
Isotopes
In total, 19 isotopes and 3 isomers with mass numbers from 243 to 256 are known. The most stable of the 252 Es isotopes has a half-life of 471.7 days .
Application
It is used to obtain mendelevium during bombardment in a cyclotron by helium nuclei [1] .