Abstract
The history of chemistry has not once seen representations of the periodic system that have not received proper attention or recognition. The present paper is dedicated to a nearly unknown version of the periodic table published on the occasion of the centenary celebration of Mendeleev’s birth (1934) by V. Romanoff. His periodic table visually merges Werner’s and Janet’s periodic tables and it is essentially the spiral periodic system on a plane. In his 1934 paper, Romanoff was the first one to introduce the idea of the actinide series, a decade before Glenn T. Seaborg, the renowned creator of the actinide concept. As a consequence, another most outstanding thing about Romanoff’s paper occurs towards its very end: he essentially predicted the discovery of elements #106, #111 and #118. He theorized that, had uranium not been the “creative limit”, we would have met element #106, a “legal” member of group 6, element #111, a precious metal, “super-gold” and element #118, a noble gas. In 2019, we take it for granted that elements #106, #111 and #118 indeed exist and they are best known as seaborgium, roentgenium and oganesson. It is fair to say that Romanoff’s success with the prediction of correct placement and chemical properties of seaborgium, roentgenium and oganesson was only made possible due to the introduction of an early version of the actinide series that only had four elements at that time. Sadly, while Professor Romanoff was imprisoned (1938–1943), two new elements, neptunium (element #93) and plutonium (element #94) were discovered. While Professor Romanoff was in exile in Ufa (1943–1953), six further elements were added to the periodic table: americium (element #95), curium (element #96), berkelium (element #97), californium (element #98), einsteinium (element #99) and fermium (element #100). The next year after his death, in 1955, mendelevium (element #101), was discovered. Romanoff’s version of the periodic table is an unparalleled precursor to the contemporary periodic table, and is an example of extraordinary anticipation of the discovery of new chemical elements.
D.I. Mendeleev and Periodic system. Continued