This Day in Science History - February 12 - Dirk Coster and Hafnium

February 12th marks the passing of Dirk Coster. Coster was a Dutch physicist who co-discovered the element hafnium with George Charles von Hevesy.

For many years, element 72 was a missing spot in the periodic table. Several chemists searched for the element in zirconium minerals since many of these minerals had unknown impurities. Since the mid-1800s, many believed they had found element 72 in these minerals and an assortment of names were proposed. Swedish chemist Lars Svanberg reported his find as norium. Henry Clifton Sorby observed a new spectral line in zirconium and named his discovery jargonium, but retracted his claim the following year due to experimental error. Tellef Dahl believed he had discovered Norwegium. Other claims of ostranium, nigrium, euxenium were announced. French chemist Georges Urbain announced he had isolated element 72 from a rare-earth sample and named it celtium. Russian chemist Nenadkevich thought he had isolated thorium in the mineral orthite, but it had a much lower atomic weight, one that would correspond to element 72. He named his discovery asium, but could not publish his find due to World War I and the Russian Civil War.

Coster and Hevesy would find their element 72 in a zircon mineral by x-ray spectroscopy. They had been working in Neils Bohr's laboratory when Bohr won his Nobel Prize. Coster notified Bohr of the discovery and wanted to name it hafnium, after the Latin name of Copenhagen. Bohr wanted to name it danium, but he accepted Coster's name. Bohr amended his Nobel lecture to include the announcement of the discovery.

Hafnium has a very busy history. Find out what else occurred on this day in science history.

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This Day in Science History - February 13 - �tienne Geoffroy

February 13th is ?tienne Fran?ois Geoffroy's birthday. Geoffroy was a French physician and chemist who was the first to arrange the known elements into a table based on their chemical affinity to each other.

Anyone who has ever mixed two items together knows some things combine better than others. In chemistry, two different chemical species' affinity is a property that shows how likely a chemical reaction will occur when mixed. Reagents with strong affinity are more likely to react with each other than reagents with little affinity to each other. Geoffroy's table had a series of reagents across the top with other reagents with high affinity with these elements listed below. This table became a standard table for 18th Century chemists until the end of the century when it was shown the amount of a reagent drove the reaction.

Find out what else occurred on this day in science history.

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This Day in Science History - February 14 - Julius Nieuwland

February 14th is the birthday of Julius Nieuwland. Nieuland was a Belgian priest and chemist who's research into the chemistry of acetylene directly led to the first commercially successful artificial rubber, polychloroprene. This is better known by DuPont's trademark, neoprene.

Nieuwland discovered he could polymerize acetylene into a rubber-like jelly of divinyl acetylene. The story might have ended there except Elmer Bolton of DuPont attended a lecture of Nieuwland's. Many industries were looking for an alternative source of rubber. Rubber is a natural product produced from latex of the para rubber tree. The majority of the world's rubber came from plantations in the Amazonian rainforest. Chemical engineers around the world were trying to discover a useful synthetic alternative. Bolton acquired the rights to further develop Nieuwland's discovery for DuPont. Scientists at DuPont collaborated with Nieuwland to produce neoprene.

Nieuland is also known for his discovery of the chemical weapon lewisite. He discovered the reaction during his acetylene research, but abandoned further research because of it's poisonous nature. When his research was weaponized to produce lewisite, he nearly gave up chemical research entirely. Find out what else occurred on this day in science history.

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