Jean Stas
Encyclopedia
Jean Servais Stas was a Belgian
analytical chemist
.
and trained initially as a physician
. He later switched to chemistry
and worked at the École Polytechnique
in Paris
under the direction of Jean-Baptiste Dumas
. Stas and Dumas established the atomic weight
of carbon
by weighing a sample of the pure material, burning it in pure oxygen, and then weighing the carbon dioxide produced.
In 1840, Stas was appointed professor at the Royal Military School
in Brussels
. He acquired international fame by determining the atomic weights of the elements more accurately than had ever been done before, using an atomic mass of 16 for oxygen
as his standard. His results disproved the hypothesis of the English physicist William Prout
that all atomic weights must be integral multiples of that of hydrogen
. These careful, accurate atomic weight measurements of Stas helped lay the foundation for the periodic system of elements
of Dmitri Mendeleev
and others.
In 1850 Stas gave the evidence that the Belgian Count Hypolyte Visart de Bocarmé killed his brother-in-law by poisoning with nicotine
Stas retired in 1869 because of problems with his voice caused by a throat ailment. He became commissioner of the mint, but resigned in 1872 because he disagreed with the government's monetary policy. Jean Stas died in Brussels
and was buried at Leuven.
Belgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...
analytical chemist
Chemistry
Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
.
Life and work
Stas was born in LeuvenLeuven
Leuven is the capital of the province of Flemish Brabant in the Flemish Region, Belgium...
and trained initially as a physician
Physician
A physician is a health care provider who practices the profession of medicine, which is concerned with promoting, maintaining or restoring human health through the study, diagnosis, and treatment of disease, injury and other physical and mental impairments...
. He later switched to chemistry
Chemistry
Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
and worked at the École Polytechnique
École Polytechnique
The École Polytechnique is a state-run institution of higher education and research in Palaiseau, Essonne, France, near Paris. Polytechnique is renowned for its four year undergraduate/graduate Master's program...
in Paris
Paris
Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...
under the direction of Jean-Baptiste Dumas
Jean-Baptiste Dumas
Jean Baptiste André Dumas was a French chemist, best known for his works on organic analysis and synthesis, as well as the determination of atomic weights and molecular weights by measuring vapor densities...
. Stas and Dumas established the atomic weight
Atomic weight
Atomic weight is a dimensionless physical quantity, the ratio of the average mass of atoms of an element to 1/12 of the mass of an atom of carbon-12...
of carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
by weighing a sample of the pure material, burning it in pure oxygen, and then weighing the carbon dioxide produced.
In 1840, Stas was appointed professor at the Royal Military School
Royal Military Academy (Belgium)
The Royal Military Academy is the military university of Belgium. The school is responsible for the education of the officers of the four components of the Belgian defence . The school is located in Brussels in a building construct by the architects Henri Maquet and Henri Van Dievoet...
in Brussels
Brussels
Brussels , officially the Brussels Region or Brussels-Capital Region , is the capital of Belgium and the de facto capital of the European Union...
. He acquired international fame by determining the atomic weights of the elements more accurately than had ever been done before, using an atomic mass of 16 for oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
as his standard. His results disproved the hypothesis of the English physicist William Prout
William Prout
William Prout FRS was an English chemist, physician, and natural theologian. He is remembered today mainly for what is called Prout's hypothesis.-Biography:...
that all atomic weights must be integral multiples of that of hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
. These careful, accurate atomic weight measurements of Stas helped lay the foundation for the periodic system of elements
Periodic table
The periodic table of the chemical elements is a tabular display of the 118 known chemical elements organized by selected properties of their atomic structures. Elements are presented by increasing atomic number, the number of protons in an atom's atomic nucleus...
of Dmitri Mendeleev
Dmitri Mendeleev
Dmitri Ivanovich Mendeleev , was a Russian chemist and inventor. He is credited as being the creator of the first version of the periodic table of elements...
and others.
In 1850 Stas gave the evidence that the Belgian Count Hypolyte Visart de Bocarmé killed his brother-in-law by poisoning with nicotine
Nicotine
Nicotine is an alkaloid found in the nightshade family of plants that constitutes approximately 0.6–3.0% of the dry weight of tobacco, with biosynthesis taking place in the roots and accumulation occurring in the leaves...
Stas retired in 1869 because of problems with his voice caused by a throat ailment. He became commissioner of the mint, but resigned in 1872 because he disagreed with the government's monetary policy. Jean Stas died in Brussels
Brussels
Brussels , officially the Brussels Region or Brussels-Capital Region , is the capital of Belgium and the de facto capital of the European Union...
and was buried at Leuven.