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Irving Langmuir was an American chemist and physicist. Born January 31, 1881 in Brooklyn, NY - Died August 16, 1957 in Woods Hole, MA

He graduated as a metallurgical engineer from the School of Mines at Columbia University in 1903. Postgraduate work in Physical Chemistry under Nobel laureate Walther Nernstunder in Göttingen earned him the degrees of M.A. and Ph.D. in 1906.

Returning to America, Dr. Langmuir became Instructor in Chemistry at Stevens Institute of Technology, Hoboken, New Jersey, where he taught until July 1909. He then entered the Research Laboratory of the General Electric Company (Schenectady, New York) where he eventually became Associate Director. While at G.E., from 1909-1950, Langmuir received 63 patents and was awarded the 1932 Nobel Prize for Chemistry.

His initial research at General Electric involved low-pressure chemical reactions and the study of the emission of electrons by hot filaments in a vacuum. This work led directly to the invention of the high vacuum electron tube in 1912 and the gas filled incandescent lamp in 1913. He also discovered atomic hydrogen, which he put to use by inventing the atomic hydrogen welding process. His studies with gases in a light bulb offered the first clear picture of thermionic emission (the flow of charged particles from hot metals). Langmuir was among the first to work with plasmas, the collection of ionized gas that possess unusual electrical and magnetic properties. He actually coined the term 'plasma' to describe those gases. Langmuir's accomplishments also include the introduction of the concept of electron temperature and of course, the invention of a device to measure it, the thermionic probe, commonly called the Langmuir probe and commonly used in plasma physics.

In his research on surface tension and surface chemistry he developed a new technique (employing monolayers, i.e., layers of molecules one molecule thick) for the study of molecules. He was the first to observe the very stable adsorbed monatomic films on tungsten and platinum filaments, and was able, after experiments with oil films on water, to formulate a general theory of adsorbed films. For his contributions in surface chemistry he received the 1932 Nobel Prize in Chemistry. He also studied the catalytic properties of such films, and discovered that the introduction of particles of dry ice and iodide into a cloud of low temperature containing sufficient moisture in tiny droplets triggered a chain reaction producing rain or snow, depending on the condition of the weather.

Langmuir's work on space charge effects and related phenomena led to many important technical developments which have had a profound effect on later technology.

Following World War I , from 1919 to 1921, his interest turned to an examination of atomic theory, and he published his "concentric theory of atomic structure" which extended the work of Gilbert Lewis on electron bonding, evolving the Lewis-Langmuir theory of atomic structure. In it he proposed that all atoms try to complete an outer electron shell of eight electrons. The inert gases already possessed this complete shell, and so were chemically unreactive. The greater tendency an atom has to complete the outer shell, the greater its chemical activity. He proposed that chemical activity was based on the number and position of electrons in the atom. If the atom in question shared electrons to complete its shell, it formed a "non-polar union"(which he called a covalent bond), while an atom that accepted or gave up electrons to accomplish this purpose formed what Langmuir called a "polar union" ( now called an ionic bond). His contributions to atomic theory and the understanding of atomic structure defined the modern concept of valence and isotopes. As part of his description of the atom, he also explained the terms isoelectronic, isomers, and isobars. Few textbooks recognize the influence that Langmuir had on the development of our understanding of the nature of the atom.

He married Marion Mersereau in 1912. They had a son, Kenneth, and a daughter, Barbara.

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-He graduated with a B.S. from the [[Columbia University]] School of Mines in 1903 and did postgraduate work in chemistry under Nobel laureate Walther Nernstunder in Göttingen and earned his  Ph.D. degree in 1906.
+He graduated as a metallurgical engineer from the School of Mines at [[Columbia University]] in 1903. Postgraduate work in Physical Chemistry under Nobel laureate Walther Nernstunder in Göttingen earned him the degrees of M.A. and Ph.D. in 1906.
-Langmuir then taught at [[Stevens Institute of Technology]] in Hoboken, New Jersey, until 1909, when he began working at the [[General Electric]] research laboratory (Schenectady, New York). While at G.E., from 1909-1950, Langmuir advanced several basic fields of physics and chemistry, invented the gas filled incandescent lamp, the hydrogen welding technique, and was awarded the 1932 [[Nobel Prize/Chemistry|Nobel Prize for Chemistry]] for his work in surface chemistry.
+Returning to America, Dr. Langmuir became Instructor in Chemistry at [[Stevens Institute of Technology]], Hoboken, New Jersey, where he taught until July 1909. He then entered the Research Laboratory of the [[General Electric]] Company (Schenectady, New York) where he eventually became Associate Director. While at G.E., from 1909-1950, Langmuir received 63 patents and was awarded the 1932 Nobel Prize for Chemistry.
+His initial research at General Electric involved low-pressure chemical reactions and the study of the emission of electrons by hot filaments in a vacuum. This work led directly to the invention of the high [[Vacuum Tube|vacuum electron tube]] in 1912 and the gas filled incandescent lamp in 1913. He  also discovered atomic [[hydrogen]], which he put to use by inventing the atomic hydrogen welding process. His studies with gases in a light bulb offered the first clear picture of thermionic emission (the flow of charged particles from hot metals). Langmuir was among the first to work with [[plasma]]s, the collection of ionized gas that possess unusual electrical and magnetic properties. He actually coined the term 'plasma' to describe those gases. Langmuir's accomplishments also include the introduction of the concept of electron temperature and of course, the invention of a device to measure it, the thermionic probe, commonly called the Langmuir probe and commonly used in [[plasma physics]].
+In his research on [[surface tension]] and surface chemistry he developed a new technique (employing monolayers, i.e., layers of molecules one molecule thick) for the study of molecules. He was the first to observe the very stable adsorbed monatomic films on [[tungsten]] and [[platinum]] filaments, and was able, after experiments with oil films on water, to formulate a general theory of adsorbed films. For his contributions in surface chemistry he received the 1932 [[Nobel Prize/Chemistry|Nobel Prize in Chemistry]]. He also studied the catalytic properties of such films, and discovered that the introduction of particles of dry ice and iodide into a cloud of low temperature containing sufficient moisture in tiny droplets triggered a chain reaction producing rain or snow, depending on the condition of the weather.
+Langmuir's work on [[space charge]] effects and related phenomena led to many important technical developments which have had a profound effect on later technology.
+Following World War I , from 1919 to 1921, his interest turned to an examination of atomic theory, and he published his "concentric theory of atomic structure" which extended the work of Gilbert Lewis on electron bonding, evolving the Lewis-Langmuir theory of [[atomic physics|atomic structure]]. In it he proposed that all atoms try to complete an outer electron shell of eight electrons. The inert gases already possessed this complete shell, and so were chemically unreactive. The greater tendency an atom has to complete the outer shell, the greater its chemical activity. He proposed that chemical activity was based on the number and position of electrons in the atom. If the atom in question shared electrons to complete its shell, it formed a "non-polar union"(which he called a [[covalent bond]]), while an atom that accepted or gave up electrons to accomplish this purpose formed what Langmuir called a "polar union" ( now called an [[ionic bond]]). His contributions to atomic theory and the understanding of atomic structure defined the modern concept of valence and isotopes. As part of his description of the atom, he also explained the terms isoelectronic, isomers, and isobars. Few textbooks recognize the influence that Langmuir had on the development of our understanding of the nature of the atom.
+He married Marion Mersereau in 1912. They had a son, Kenneth, and a daughter, Barbara.