Sunday, July 13, 2014

Stanislao Cannizzaro

Stanislao Cannizzaro was born on July 13, 1826 in Palermo, Sicily, the fourth and youngest son of Mariano Cannizzaro and his wife Anna. Mariano was a magistrate in Palermo and the Director-General of the Sicilian Police. Cannizzaro was educated at home and in church schools and went to the University of Palermo to study medicine in 1841. Cannizzaro found the study of medicine to be tedious as he was more interested in chemistry. Unfortunately the university did not have facilities to study chemistry so Cannizzaro went to Naples where he met the physicist Macedonio Melloni, with whom he became friends and upon Melloni's recommendation he got a job working in the chemical laboratories of the University of Pisa working for Raffeal Piria.

Cannizzaro returned to Palermo in 1847 and served as an artillery officer in the 1848 rebellion. Also in 1848 he was elected to the Sicilian Parliament and served as its youngest member. After the fall of Messina on September 7, 1848 Cannizzaro was sent to Taorminna to organize resistance. When the rebellion collapsed Cannizzaro lived a life on the run eventually escaping to Marseilles, France in 1849. Cannizzaro toured France getting access to laboratories where he could and eventually he settled in Alessandria, Italy where he got a position as a professor of physical chemistry and mechanics at the National University in Alessandria. In 1855 Cannizzaro was called to the Chair of Chemistry at the University of Genoa. In 1861 he took a professorship at the University of Palermo where he remained for ten years. In 1871 Cannizaro was called to the professorship at the University of Rome.

Cannizzaro is most remembered for his work popularizing the ideas of another Italian chemist Amedeo Avagadro. Avagadro had proposed that equal volumes of two gasses at the same temperature and pressure would contain the same number of molecules and that the molecular mass of the molecules would be the sum of the atomic masses of the atoms of which the gasses are composed. Using this principal Cannizzaro developed a method for determining the molecular masses of gasses. At the time chemists were still trying to work out the uses of the words atomic and molecular. Cannizzaro's outline, prepared for his students at the University of Genoa, helped chemists understand that gasses are molecules composed of multiple atoms and have the molecular mass of the sum of the atomic masses of the atoms of which they are composed. For example, oxygen gas, composed of two oxygen atoms each having the atomic mass of 16, has the molecular mass of 32. For his work contributing to the understanding of the concepts of atom and molecule Cannizzaro was awarded the Copley Medal by the Royal Society of London in 1891,

Cannizzaro is also remembered for his work in organic chemistry, where he studied amines and aromatic compounds. Aromatic compounds are compounds that contain a benzene ring. The Cannizzaro reaction is the reaction where an aldehyde is reacted with a base and the reaction produces the alcohol and carboxylic acid that correspond to the aldehyde.

Cannizaro died on May 10, 1910.


Anon.; "Stanislao Cannizaro"; retrieved from

Thorpe, Sir Thomas Edward; "Stanislao Canniaro" in Essays in Historical Chemistry; MacMillian and Co.; 1902

Stanislao Cannizaro Wikipedia Entry

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