Harold Johann Thomas Ellingham,

OBE The Most Excellent Order of the British Empire is a British order of chivalry, rewarding valuable service in a wide range of useful activities. It comprises five classes of awards across both civil and military divisions, the most senior two o ...

, (1897–1975) was a British physical chemist, best known for his

Ellingham diagram An Ellingham diagram is a graph showing the temperature dependence of the stability of compounds. This analysis is usually used to evaluate the ease of reduction of metal oxides and sulfides. These diagrams were first constructed by Harold Ellin ...

s, which summarize a large amount of information concerning extractive

metallurgy Metallurgy is a domain of materials science and engineering that studies the physical and chemical behavior of metallic elements, their inter-metallic compounds, and their mixtures, which are known as alloys. Metallurgy encompasses both the ...

.. Ellingham was born in Tottenham on 21 November 1897, the son of Thomas Robert Ellingham (fine art designer) and Katherine Caroline Bauer. He studied at the

Royal College of Science The Royal College of Science was a higher education institution located in South Kensington; it was a constituent college of Imperial College London from 1907 until it was wholly absorbed by Imperial in 2002. Still to this day, graduates from t ...

from 1914 to 1916.Although the

had been formally merged with the

Royal School of Mines The Royal School of Mines comprises the departments of Earth Science and Engineering, and Materials at Imperial College London. The Centre for Advanced Structural Ceramics and parts of the London Centre for Nanotechnology and Department of Bioe ...

and the

City and Guilds Central Technical College The City and Guilds of London Institute is an educational organisation in the United Kingdom. Founded on 11 November 1878 by the City of London and 16 livery companies to develop a national system of technical education, the institute has bee ...

in 1907 to form the

Imperial College of Science and Technology Imperial College London, also known as Imperial, is a public research university in London, England. Its history began with Prince Albert, husband of Queen Victoria, who envisioned a cultural district in South Kensington that included museums, ...

, it retained an independent identity as a constituent college until 2002. During the war years he served as a lieutenant in the Royal Engineers, in Mesopotamia (1917-1919) and India (May-June 1919). On returning to the College he became a demonstrator at the college in 1919 and reader in physical chemistry in 1937. He was secretary of the Royal College of Science 1940–44 and of the

Royal Institute of Chemistry The Royal Institute of Chemistry was a British scientific organisation. Founded in 1877 as the Institute of Chemistry of Great Britain and Ireland (ICGBI), its role was to focus on qualifications and the professional status of chemists, and its ai ...

1944–63. He was made a fellow of

Imperial College Imperial College London, also known as Imperial, is a public research university in London, England. Its history began with Prince Albert, husband of Queen Victoria, who envisioned a cultural district in South Kensington that included museums ...

in 1949 and an

Officer of the Order of the British Empire The Most Excellent Order of the British Empire is a British order of chivalry, rewarding valuable service in a wide range of useful activities. It comprises five classes of awards across both civil and military divisions, the most senior two o ...

(OBE) in 1962.. Ellingham is best known for his diagrams plotting the

Gibbs energy In thermodynamics, the Gibbs free energy (or Gibbs energy as the recommended name; symbol is a thermodynamic potential that can be used to calculate the maximum amount of work, other than pressure–volume work, that may be performed by a ther ...

change for the reaction : M + O₂ against temperature. By normalizing the thermodynamic functions to the reaction with one mole of

oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...

, Ellingham was able to compare the temperature stability of many different

oxide An oxide () is a chemical compound containing at least one oxygen atom and one other element in its chemical formula. "Oxide" itself is the dianion (anion bearing a net charge of −2) of oxygen, an O2− ion with oxygen in the oxidation st ...

s on the same diagram. In particular, he could show graphically that

carbon Carbon () is a chemical element; it has chemical symbol, symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent—meaning that its atoms are able to form up to four covalent bonds due to its valence shell exhibiting 4 ...

becomes a stronger reducing agent as the temperature increases. The reduction of metal oxides with carbon (or

carbon monoxide Carbon monoxide (chemical formula CO) is a poisonous, flammable gas that is colorless, odorless, tasteless, and slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the si ...

) to form the free metals is of immense industrial importance (e.g., the manufacture of

iron Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's o ...

in a

blast furnace A blast furnace is a type of metallurgical furnace used for smelting to produce industrial metals, generally pig iron, but also others such as lead or copper. ''Blast'' refers to the combustion air being supplied above atmospheric pressure. In a ...

), and

s show the lowest temperature at which the reaction will occur for each metal. He married Doris Karin Russell in Kensington in 1945. He died in

Harrow Harrow may refer to: Places * Harrow, Victoria, Australia * Harrow, Ontario, Canada * The Harrow, County Wexford, a village in Ireland * London Borough of Harrow, England * Harrow, London, a town in London * Harrow (UK Parliament constituency) * ...

on 19 December 1975. Doris died in

Hawkhurst Hawkhurst is a village and civil parish in the borough of Tunbridge Wells in Kent, England. The village is located close to the border with East Sussex, around south-east of Royal Tunbridge Wells and within the High Weald Area of Outstanding N ...

on 27 September 1984.

Notes and references

Notes

References

{{DEFAULTSORT:Ellingham, Harold Johann Thomas British chemists 1897 births 1975 deaths Alumni of the Royal College of Science Academics of Imperial College London