PROMETHIUM

Until the year 1950, when by then a good chunk of today's periodic table had been chartered, two elements remained the gnat in the elephant's side for the element-hunters of that time period. Namely, elements of atomic numbers 43 and 61, which existed in the midst of stable elements. The search for this elusive elements began about the time of Mendeleev's first periodic table, and eventually as more elements were found in nature and 43 and 61 remained out of view, as if they were a war criminal hiding for their life out in a hole somewhere in the desert. So eventually the assumption became that 43 and 61 were radioactive elements - which turned out correct. In 1945 the 61st element was found at last - and an annoying little bit of periodic table was at last chartered. The element's name, Promethium, was suggested as it was felt that Prometheus bringing fire from the heavens was a nice motif to associate with the discovery of a new element.

For some time promethium was used in a halide form in glow in the dark paint. But many of these sources are now nearly depleted, as promethium has a half life of only 2 years in its most used isotope. [longest half life: 17 years] So, this sample is not one of such. In nature, promethium is found only in minute quantities - either from the fission of uranium, or the decay of the long-lived Europium 151 which accounts for about half of all natural Europium. The glowing powder in this vial contains europium, so most likely has promethium in atomic quantities too. This sample was prepared in July of 2025, which saw the completion of the lanthanide series in my periodic table.