Richard Zsigmondy

Zsigmondy did much of the early work to explain and characterize colloids, mixtures in which particles of a substance are dispersed throughout another. He developed the ultramicroscope as a tool to study colloids.

Born:April 1, 1865; Vienna, Austrian Empire (now in Austria) Died:September 24, 1929; Göttingen, Germany Also known as:Richard Adolf Zsigmondy (full name) Primary field:Chemistry Primary invention:Ultramicroscope

Early Life

Richard Adolf Zsigmondy (ZHIHG-mawn-dee) was the fourth child born to Adolf Zsigmondy and Irma von Szakmary. Adolf was a well-respected, innovative dentist and head of Vienna General Hospital’s surgical department. Adolf died when Richard was fifteen years old. Richard went to Vienna’s public school in the Josefstadt District, receiving his secondary school degree in 1883. He then began studies at the Vienna Institute of Technology. In 1885, he published a paper with one of his teachers, Rudolf Benedict, on the detection of glycerin. In 1887, he moved to the Technical University of Munich to study organic chemistry. His dissertation, on the synthesis of indene derivatives, was accepted, and he received his Ph.D. from the University of Erlangen in 1889.

At about the same time, Zsigmondy published some of his first papers on the coloring of glass, a subject that would be important to him for his entire career. This research involved silver salts and silver particles, which caused the coloring of the glass and which could be recovered by using hydrofluoric acid to dissolve the glass. In 1891 and 1892, Zsigmondy was an assistant to physicist August Kundt. During this time, Zsigmondy researched the diathermaneity (the property of transmitting radiant heat) of glasses and ferrous salts. His research in this area brought him into contact with Otto Schott, whose laboratory in Jena was doing research in glasses. Zsigmondy and Schott would later collaborate, studying the thermal transmittance of different glasses and producing a glass that would not transmit heat rays.

Life’s Work

In 1893, Zsigmondy became a teaching assistant at the Graz University of Technology. That summer, he presented a colloquium and lecture that were praised by the professors at the school and earned him a teaching qualification (habilitation). Zsigmondy taught at Graz from 1893 to 1897. He was an outstanding lecturer, and during this time he began his in-depth study of colloids. His first study was a glass dye generated by gold particles, known as “purple of Cassius” (named for its discoverer, the seventeenth century alchemist Andreas Cassius). At that time, there were two views on the nature of purple of Cassius: One stated that it was a chemical compound, a view held by the prominent Swedish chemist Jöns Jakob Berzelius; the other held that it was a “mixture of finely divided gold and stannic acid.” Zsigmondy’s experiments determined that the latter view was correct.

In October of 1897, Schott offered Zsigmondy a position at the Schott Glass Manufacturing Company in Jena. Zsigmondy worked there until 1900 and had many outstanding accomplishments in both the study of colloids and the practical application of the knowledge in the coloring of glasses. His Jena milk glass and his work with colored and turbid glasses earned Zsigmondy a sterling reputation. When he left Schott’s company, he became a private researcher in Jena.

In 1903, Zsigmondy built and introduced the ultramicroscope to study particles smaller than could be seen in a regular microscope. The ultramicroscope was a result of collaboration with H. F. W. Siedentopf, a physicist with the Zeiss Company of Jena. In June of that year, Zsigmondy married Laura Luise Müller, with whom he had two daughters, Annemarie and Käthe. Zsigmondy introduced the immersion ultramicroscope, an improvement to the original ultramicroscope, ten years later. During his time in Jena, he wrote two noteworthy overviews of colloids. In 1907, he was offered an associate professorship at the University of Göttingen. In 1908, he was named director of the Institute of Inorganic Chemistry, a position he held until his retirement in 1929, and became a full professor in 1919. For several years after World War I, inflation was so bad that the institute ran short of the necessary materials for top-quality research.

Zsigmondy was awarded the 1925 Nobel Prize in Chemistry “for his demonstration of the heterogenous nature of colloid solutions and for the methods he used.” When he won his Nobel Prize, he stated the work that he did at Graz was the beginning of his knowledge of colloids. He was searching for glass dyes, and his experimental results could not be explained by the current knowledge of chemistry.

Thomas Graham (1805-1869) had been the first to differentiate between crystalloid and colloid solutions. He observed that crystalloid solutions quickly diffused through parchment paper, leaving no residue, whereas colloid solutions such as gelatin hardly diffused through the membrane. Zsigmondy found that sometimes the same substance formed a colloid solution under one set of conditions and a crystalloid solution under a different set of conditions.

Zsigmondy was interested in making colored glass and ceramics of a consistent color. Some of his work in glass involved making a glass, noting its color, dissolving it in hydrofluoric acid, and measuring the amount of particles in the glass. Using his ultramicroscope, he was able to detect particles in the colloid solutions that were not visible with a regular microscope. He determined that the difference in the two types of solutions was the particle size of the molecules, which were larger in colloid solutions. Thus, he confirmed that colloid solutions were not homogeneous.

Zsigmondy discovered that different size particles of the same material produced different colors in glass. Using the ultramicroscope, he was able to calculate the size of the particles by counting the number of particles in a volume. For particles that were too small to see with the ultramicroscope, Zsigmondy invented the nucleus method, which was first applied to gold particles. The colloid particles were placed in a reducing solution in which metal was precipitated; the precipitating metal then settled on the colloid particles until they could be seen in the ultramicroscope. With this process, gold colloidal particles as small as one ten-millionth of a millimeter were visible in sunlight. The study of different size particles led Zsigmondy to develop a theory of coagulation, the formation of colloids by small particles aggregating together. He measured the speed of coagulation and the final size of a particle, among other variables.

During his time in Göttingen, Zsigmondy developed membrane filters with Wilhelm Bachmann. In 1922, the ultrafine filter was developed as an improvement to the membrane filters. Zsigmondy also worked on different types of colloidal solutions, including silicic acids and soap gels. His work with gold sols helped him to develop his theory of coagulation. Zsigmondy published a textbook about colloids, Lehrbuch der Kolloidchemie (1912), which was revised several times, and reviewers praised his writings for their clear explanations. Zsigmondy taught at Göttingen until 1929, retiring because of acute arteriosclerosis. He died a few months later.


Zsigmondy led in the study of colloids and their uses. He conclusively demonstrated that colloids are not the homogeneous solutions that they were thought to be. He also helped explain why some colloidal solutions do not have the same properties of others: The particles are coagulated instead of behaving as individual particles. Zsigmondy developed the methods to study colloids, such as ultramicroscopy and the nuclear method.

Colloids are prevalent in the world. They can occur in gaseous, liquid, or solid states. Colloid particles are larger—a micrometer to a nanometer in diameter—than most individual molecules. Examples of colloids are fog, whipped cream, mayonnaise, marshmallows, Jello, jellies, detergents in water, starch, proteins, water glass, glue, albumin, and rubber. Depending on the colloid particle and the state of the solution, colloid solutions may be called aerosol, foam, emulsion, sol, gel, or colloidal solid. Zsigmondy’s research has been especially beneficial in fields of biochemistry and bacteriology.

—C. Alton Hassell

Further Reading

Chernoberezhskii, Yu. M., I. S. Rudakova, and A. V. Lorentsson. “Spectrophotometric and Flow Ultramicroscopic Study of the Aggregation and Sedimentation Stability of Aqueous Dispersions of Sulfate Lignin in a pH Range of 12.0-2.3.” Colloid Journal 69, no. 2 (April, 2007): 237-239 . Ar t ic le show ing tha t Zs igmondy’s field of colloids and his technique of ultramicroscopy are just as significant today as they were in his day. World Scientific. Nobel Lectures in Chemistry, 1922-

  1. River Edge, N.J.: Author, 1999. Includes speeches and short biographies of Nobel Prize winners, including Zsigmondy. Illustrations. Zsigmondy, Richard. Colloids and the Ultramicroscope:

A Manual of Colloid Chemistry and Ultramicroscopy. Translated by Jerome Alexander. New York: John Wiley & Sons, 1909. Zsigmondy describes his work. Illustrations, bibliography, index.

_. One Hundred Years of Nanoscience with the Ultramicroscope: The Work of Richard Zsigmondy. Introduction by Carsten Sönnichsen and Wolfgang Fritzsche. Aachen, Germany: Shaker/Verlag, 2007. Contains a short biographical section and a translation of a talk given by Zsigmondy in 1907 on colloidal chemistry. Illustrations, bibliography.


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