Back in the 1940s Glenn T. Seaborg and his transuranium team in Berkeley (CA) started to extend the periodic table of the elements by neptunium, plutonium, americium, curium, berkelium, californium, einsteinium, fermium, mendelevium, nobelium and lawrencium. Before they reached the so-called fermium barrier this was possible by bombarding suitable uranium or transuranium isotopes with neutrons. Beginning with fermium, however, no elements with atomic numbers larger than 100 and masses heavier than 257 can be synthesized this way. So mendelevium, nobelium and lawrencium needed to be obtained by fusion of transuranium targets with atomic particles such as helium, boron or carbon in order to complete the actinoid series. For the discovery of most transactinoid elements even heavier species like oxygen (Berkeley, USA), neon and chromium (Dubna, Russia), iron (Darmstadt, Germany) or zinc (Wako, Japan) were accelerated to hit either transuranium or lead targets. Obtained and isolated by one of these sophisticated methods, element 106 was named after Seaborg (1912 − 1999) himself, while he was still alive. With more than a million years of half-life, several isotopes of plutonium, neptunium and curium allow even a rather lazy preparative chemistry to synthesize and characterize their plethora of compounds. For americium, the longest half-life isotope lasts for almost 7500 years only and this time shortens for berkelium to 1400 years and for californium to 2700 years. Thomas E. Albrecht-Schmitt and his team in Tallahassee (FL) brilliantly perform their difficult hydrothermal and solid-state chemistry, especially with his favorite oxoanions borate, phosphate, selenate and iodate like no one before to bask in the glow. Half-lifes of little more than 1 year and just 100 days for einsteinium and fermium, respectively, seem to hamper the chemistry of these super-heavy "post-californians" drastically and most probably make einsteinium the final frontier for chemistry on the edge of stability.<br/>

From Glenn T. Seaborg via the transuranium elements to Thomas E. Albrecht-Schmitt

2019 Spring National Meeting

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