Hendrik Willem Bakhuis Roozeboom
H. W. Bakhuis Roozeboom (ˈɦɛndrɪk ˈʋɪləm ˈbɑkɦœy̯s ˈroːzəˌboːm, October 24, 1854 - February 8, 1907) was a Dutch
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...

 chemist who gained his reputation for works on phase behaviour in physical chemistry
Physical chemistry
Physical chemistry is the study of macroscopic, atomic, subatomic, and particulate phenomena in chemical systems in terms of physical laws and concepts...


H. W. Bakhuis Roozeboom (originally "Bakhuys Roozeboom") was born in Alkmaar
Alkmaar is a municipality and a city in the Netherlands, in the province of Noord Holland. Alkmaar is well known for its traditional cheese market. For tourists, it is a popular cultural destination.-History:...

 in the 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...

. Financial difficulties did not allow him to directly pursue a university education, and he left school to work in a chemical factory for some time. Due to support from his mentor, J. M. van Bemmelen, he became an assistant at the University of Leiden in 1878, which enabled him to start his academic education there. In 1881 he became a teacher at a girls school, and in 1884 he obtained his PhD with works on the hydrate
Hydrate is a term used in inorganic chemistry and organic chemistry to indicate that a substance contains water. The chemical state of the water varies widely between hydrates, some of which were so labeled before their chemical structure was understood....

s of acid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...

s. J. D. van der Waals
Johannes Diderik van der Waals
Johannes Diderik van der Waals was a Dutch theoretical physicist and thermodynamicist famous for his work on an equation of state for gases and liquids....

 introduced him to the theoretical works of J. Willard Gibbs
Josiah Willard Gibbs
Josiah Willard Gibbs was an American theoretical physicist, chemist, and mathematician. He devised much of the theoretical foundation for chemical thermodynamics as well as physical chemistry. As a mathematician, he invented vector analysis . Yale University awarded Gibbs the first American Ph.D...

 on the phase rule which so far had little experimental verification in chemistry, prompting him to start a lifelong research programme on phase equilibria. In 1896, he became professor for chemistry in 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...

, where he died in 1907.

His main work was in the field of thermodynamics
Thermodynamics is a physical science that studies the effects on material bodies, and on radiation in regions of space, of transfer of heat and of work done on or by the bodies or radiation...

, in which he studied the equilibrium of multiple-phase systems. The theoretical foundations for this were laid by J. Willard Gibbs with his phase rule, but Roozeboom would be the one to apply the theory and demonstrate its usefulness. He is mainly remembered for his melting phase diagrams of metal alloy
An alloy is a mixture or metallic solid solution composed of two or more elements. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may or may not be homogeneous in distribution, depending on thermal history...

s, i.e. studying how mixtures of metals melt depending on the relative amounts of the components, which is important for metallurgy
Metallurgy is a domain of materials science that studies the physical and chemical behavior of metallic elements, their intermetallic compounds, and their mixtures, which are called alloys. It is also the technology of metals: the way in which science is applied to their practical use...

. Roozeboom also was the first to plot ternary phase equilibria in two-dimensional plots that were taken as vertical or horizontal slices from the three-dimensional solid diagrams. These are termed, respectively, isopleths and isotherms. He also contributed to the science of chiral
Chirality (chemistry)
A chiral molecule is a type of molecule that lacks an internal plane of symmetry and thus has a non-superimposable mirror image. The feature that is most often the cause of chirality in molecules is the presence of an asymmetric carbon atom....

 substances, clarified how to distinguish the different types of crystalline racemates and predicted how mixtures of enantiomer
In chemistry, an enantiomer is one of two stereoisomers that are mirror images of each other that are non-superposable , much as one's left and right hands are the same except for opposite orientation. It can be clearly understood if you try to place your hands one over the other without...

s behave in a heterogeneous system of solid and solution.

Roozeboom succeeded J. H. van't Hoff at the University of Amsterdam. In 1904, he published the first volume and first part of the second volume of the multi-volume treatise on heterogeneous equilibria entitled Die Heterogenen Gleichgewichte von Standpunkte des Phosenlehre "Heterogeneous Equilibria from the Phase Rule Viewpoint."

In 1911, the Bakhuys Roozeboom Fund was established in his honour; every four years it awards a gold medal for research on phase theory.
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