Jeremias Benjamin Richter (; 10 March 1762 – 4 May 1807) was a German

chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a graduated scientist trained in the study of chemistry, or an officially enrolled student in the field. Chemists study the composition of ...

. He was born at Hirschberg in

Silesia Silesia (see names #Etymology, below) is a historical region of Central Europe that lies mostly within Poland, with small parts in the Czech Silesia, Czech Republic and Germany. Its area is approximately , and the population is estimated at 8, ...

, became a mining official at Breslau in 1794, and by 1800 was appointed assessor to the department of mines and chemist to the royal porcelain factory at

Berlin Berlin ( ; ) is the Capital of Germany, capital and largest city of Germany, by both area and List of cities in Germany by population, population. With 3.7 million inhabitants, it has the List of cities in the European Union by population withi ...

, where he died. He is known for introducing the term ''

stoichiometry Stoichiometry () is the relationships between the masses of reactants and Product (chemistry), products before, during, and following chemical reactions. Stoichiometry is based on the law of conservation of mass; the total mass of reactants must ...

''.

Developer of titration

He made some of the earliest known determinations of the quantities by weight in which

acids An acid is a molecule or ion capable of either donating a proton (i.e. hydrogen cation, H+), known as a Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis acid. The first category of acids are the ...

saturate bases and bases acids. He realised that those amounts of different bases which can saturate the same quantity of a particular acid are equivalent to each other (see ''

Titration Titration (also known as titrimetry and volumetric analysis) is a common laboratory method of Quantitative research, quantitative Analytical chemistry, chemical analysis to determine the concentration of an identified analyte (a substance to be ...

''). He was thus led to conclude that chemistry is a branch of applied mathematics and to endeavour to trace a law according to which the quantities of different bases required to saturate a given acid formed an arithmetical progression, and the quantities of acids saturating a given base a

geometric progression A geometric progression, also known as a geometric sequence, is a mathematical sequence of non-zero numbers where each term after the first is found by multiplying the previous one by a fixed number called the ''common ratio''. For example, the s ...

Law of definite proportions (
stoichiometry Stoichiometry () is the relationships between the masses of reactants and Product (chemistry), products before, during, and following chemical reactions. Stoichiometry is based on the law of conservation of mass; the total mass of reactants must ...
)

Evidence for the existence of atoms was inferred from the law of definite proportions proposed by him in 1792. Richter found that the ratio by weight of the compounds consumed in a chemical reaction was always the same. It took 615 parts by weight of magnesia (MgO), for example, to neutralize 1000 parts by weight of

sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid (English in the Commonwealth of Nations, Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen, ...

. From his data, Ernst Gottfried Fischer calculated in 1802 the first table of chemical equivalents, taking sulphuric acid as the standard with a value of 1000. When

Joseph Proust Joseph Louis Proust (26 September 1754 – 5 July 1826) was a French people, French chemist. He was best known for his discovery of the law of definite proportions in 1797, stating that chemical compounds always combine in constant proportions. ...

reported his work on the constant composition of chemical compounds, the time was ripe for the reinvention of an atomic theory. The

law of definite proportions In chemistry, the law of definite proportions, sometimes called Proust's law or the law of constant composition, states that a given chemical compound contains its constituent elements in a fixed ratio (by mass) and does not depend on its source ...

and constant composition alone do not prove that atoms exist, but their existence is difficult to explain without assuming that chemical compounds are formed when atoms combine in constant proportions.

Publications

His findings were published in Über die neueren Gegenstände in der Chemie (1792–1802) and Anfangsgründe der Stöchiometrie or Messkunst chemischer Elemente (1792–1794), but a considerable period of time elapsed before they were fully acknowledged. This was partly because some of his work was incorrectly ascribed to Carl Wenzel by Jons Berzelius which was only corrected in 1841 by Henri Hess, professor of chemistry at St. Petersburg, and author of the laws of constant heat-sums and of thermoneutrality.

Later work

Between 1792 and 1794 he published a three-volume summary of his work on the law of definite proportions. In this book Richter introduced the term

, which he defined as the ''art of chemical measurements, which has to deal with the laws according to which substances unite to form chemical compounds''. Richter was fascinated with the role of mathematics in chemistry. Unfortunately, his writing style has been described as ''obscure and clumsy''. His work therefore had little impact until 1802, when it was summarized by Ernst Gottfried Fischer in terms of tables.

Notes

References

* {{DEFAULTSORT:Richter, Jeremias 1762 births 1807 deaths People from Jelenia Góra Chemists from the Kingdom of Prussia Scientists from the Province of Silesia 19th-century German chemists 18th-century German chemists