19 April 22

Today's periodic table tie celebrates two events in the history of chemistry. Glenn Seaborg, discoverer of plutonium and other transuranium elements, was born on 19 April 1912 (and died in 1999). Pierre and Marie Curie first purified radium on 20 April 1902. On my tie, the squares for elements 104-106 are labeled "Unq," "Unp" and "Unh," from the names unnilquadium, unnilpentium and unnilhexium, which were used until more official names were adopted in 1997. Element 106, "Unh," was named seaborgium to honor Glenn Seaborg! It was the first time an element was named for a living person. Its atomic symbol is now Sg. The elements discovered by Marie and Pierre Curie -- radium (88) and polonium (84) -- and the element named for them -- curium (96) -- are not included on my tie, but they used some of the pictured standard lab equipment in their research.