Einsteinium ground state electronic configuration

Nobelium is a member of the actinide series of elements. The ground state electron configuration is assumed to be (Rn)5fl47s2, by analogy with the equivalent lanthanide element ytterbium ([Kr]4fl46s2) there has never been enough nobelium made to experimentally verify the electronic configuration. Unlike the other actinide elements and the lanthanide elements, nobelium is most stable in solution as the dipositive cation No ". Consequently its chemistry resembles that of the much less chemically stable dipositive lanthanide cations or the common chemistry of the alkaline earth elements. When oxidized to No, nobelium follows the well-estabhshed chemistry of the stable, tripositive rare earth elements and of the other tripositive actinide elements (e.g., americium and curium), see also Actinium Berkelium Einsteinium Fermium Lawrencium Mendele-vium Neptunium Plutonium Protactinium Ruthereordium Thorium Uranium. 

Electron paramagnetic resonance spectra of divalent einsteinium have been recorded in single-crystal hosts of CaFj [33], BaF2, and SrF2 [34]. Reduction of Es " to Es was spontaneous from electron displacement caused by the a radiation. A 5f configuration with a ground state close to the Ii5/2 level, but with a small admixture of the Ki5/2, was found, which indicated that the cubic crystal field only slightly perturbs the inner 5f orbitals. 

---