Ernst Julius Cohen was a Dutch

Netherlands

The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...

 Jewish chemist

Chemist

A chemist is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties such as density and acidity. Chemists carefully describe the properties they study in terms of quantities, with detail on the level of molecules and their component atoms...

 known for his work on the allotropy

Allotropy

Allotropy or allotropism is the property of some chemical elements to exist in two or more different forms, known as allotropes of these elements...

 of metal

Metal

A metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...

s. Cohen studied chemistry under Svante Arrhenius

Svante Arrhenius

Svante August Arrhenius was a Swedish scientist, originally a physicist, but often referred to as a chemist, and one of the founders of the science of physical chemistry...

 in Stockholm

Stockholm

Stockholm is the capital and the largest city of Sweden and constitutes the most populated urban area in Scandinavia. Stockholm is the most populous city in Sweden, with a population of 851,155 in the municipality , 1.37 million in the urban area , and around 2.1 million in the metropolitan area...

, Henri Moissan

Henri Moissan

Ferdinand Frederick Henri Moissan was a French chemist who won the 1906 Nobel Prize in Chemistry for his work in isolating fluorine from its compounds.-Biography:...

 at 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...

, and Jacobus van't Hoff at Amsterdam

Amsterdam

Amsterdam is the largest city and the capital of the Netherlands. The current position of Amsterdam as capital city of the Kingdom of the Netherlands is governed by the constitution of August 24, 1815 and its successors. Amsterdam has a population of 783,364 within city limits, an urban population...

. In 1893 he became Van't Hoff's assistant and in 1902 he became professor of Physical Chemistry at the University of Utrecht, a position which he held until his retirement in 1939. Throughout his life, Cohen studied the allotropy

Allotropy

Allotropy or allotropism is the property of some chemical elements to exist in two or more different forms, known as allotropes of these elements...

 of tin.
Cohen’s areas of research included polymorphism of both elements and compounds, photographic chemistry, electrochemistry, pizeochemistry, and the history of science. He published more than 400 papers and numerous books.

He was elected a Foreign Member of the Royal Society

Royal Society

The Royal Society of London for Improving Natural Knowledge, known simply as the Royal Society, is a learned society for science, and is possibly the oldest such society in existence. Founded in November 1660, it was granted a Royal Charter by King Charles II as the "Royal Society of London"...

 in 1926.

According to Margit Szöllösi-Janze, in her book, Science in the Third Reich, Cohen "put great efforts into restoring the relationships of Western European scientists with their German colleagues after the First World War."
He was killed March 5, 1944 in a gas chamber

Gas chamber

A gas chamber is an apparatus for killing humans or animals with gas, consisting of a sealed chamber into which a poisonous or asphyxiant gas is introduced. The most commonly used poisonous agent is hydrogen cyanide; carbon dioxide and carbon monoxide have also been used...

 at Auschwitz concentration camp

Auschwitz concentration camp

Concentration camp Auschwitz was a network of Nazi concentration and extermination camps built and operated by the Third Reich in Polish areas annexed by Nazi Germany during World War II...

.

Literary works

• "J. H. van 't Hoff
  Jacobus Henricus van 't Hoff
  Jacobus Henricus van 't Hoff, Jr. was a Dutch physical and organic chemist and the first winner of the Nobel Prize in chemistry. He is best known for his discoveries in chemical kinetics, chemical equilibrium, osmotic pressure, and stereochemistry...
  
  , his life and work", 1912
• "Impressions of the Land of Benjamin Franklin", 1928

External links

• http://www.chemistry.org.il/booklet/9/pdf/weintraub.pdf Weintraub, B. (2003). Tin Disease and Ernst Julius Cohen (1869-1944); Chemistry in Israel, Bull. Isr. Chem. Soc., Issue 9, Apr. 2002, p 31-32.