A   history on chemical valence as a contribution to chemistry education. It’s common in an elementary organic chemistry course to talk about Kekulé and his insights. He argued that just as every element has an atomic weight, it also has only one atomicity. By atomicity, he meant valence. Based on this assumption, which, in fact, had already been questioned by …

A trip to a Muslim country My wife and I went on an almost month-long trip to Uzbekistan. A trip that we organized ourselves with patience. We knew very little about the country. The town still retains many of the architectural testimonies of the past, as an important passage area for the ancient silk road. Beautiful madrasas, caravanserais, mosques and …

The content of this article represents the completion of the work he did earlier on optical conversion. An optical antipode could only be obtained if the recemic form of the substance was obtained first. Once the racemic form was available, one intervened according to the three classical modalities already identified by Pasteur to isolate one or both enantiomers. Walden discovers …

The Story of the Discovery of Configuration Reversal by Paul Walden. The article addresses the origin of Walden’s discovery of the phenomenon of configuration reversal. The origin of this discovery is very interesting because it was born while Walden is busy confirming the asymmetric carbon hypothesis proposed by Van’t Hoff and Le Bell. Walden’s experimental work covers a period of …

The Liebig Museum and Laboratorium in Giessen in Germany thanks me! In 2017 I visited the Liebig Museum in Giessen accompanied by the chemistry professor Prof. Manfred Kroeger, member of the Board of Directors of the Justus Liebig company of Giessen of the local University, who with great willingness showed me all the historical wonders enclosed in this Museum – …

The Bunsen-Kirchhoff Spectroscope. A short time ago, while walking through the rows of stalls at the Arezzo antiques fair, held every first Sunday of the month, I noticed on the table of one of the many stalls, the barely perceptible golden reflection of a Bunsen spectroscope, almost submerged by knick-knacks of every kind. It was a long and tiring negotiation …

Heinrich Kiliani’s discoveries on the chemistry of sugars.   This first article on sugars in this blog is dedicated to the work done by  Heinrich Kiliani (1855 –1945), a German chemist. He began studying chemistry in 1873 by enrolling at the Technische Hochschule in Munich. He had Emil Erlenmeye as a chemistry teacher, who appreciated him so much that he …

Louis Pasteur was a great chemist. I met this personality, really interesting, on the occasion of a research I did at the time on the birth of Stereochemistry. Pasteur is known as a scientist in the fields of biology and medicine, but his beginnings were in the fields of crystallography and chemistry. In fact, he started with an academic preparation …

The Birth of Stereochemistry. Rain of crystals: I kept an old barrel in the cellar of my house for many years before deciding to make wood for the fireplace. Its interior walls, in the dimly lit cellar, seemed to be covered with a blackish, amorphous deposit. But when I took it outside and it was illuminated by sunlight, I felt …

Jean Beguin’s first chemical equation. The slow process of differentiation, separation of chemical practice from that complex body of philosophical and scientific knowledge that goes by the name of alchemy, began in the 17th century. The field of application and development of chemistry was medicine. The main aim was the search for new drugs, especially of inorganic origin. Minerals were …