Stamps depict Niels Bohr, the equation for the Bohr frequency condition (an equation relating to light frequency and electrons), and a diagram of the Bohr model of a hydrogen atom.

Soviet Union postage stamp commemorating Nikolay Nikolaevich Zinin (1812-1880), a Russian organic chemist who created a base of aniline, which he named benzidam.

Depicts logo of the Accra Assembly held in Ghana on June 21-28, 1962, together with three postage stamps of Ghana.

Cachet and stamps depict Nobel Prize winners from 1902.

Cuban postage stamp printed to promote world anti-malaria campaign. Depicts a chinchona plant and chemical formulas for chloroquine and primaquine, medications used to treat malaria.

Stamp depicts chemical glassware, electron microscope, molecule, and microscopic view of cell.

Stamp from the inauguration of Democritus Nuclear Research Centre in Agia Paraskevi. Depicts ancient Greek philosopher Democritus and a model of an atom.

First Day Cover commemorating the inauguration of the atomic reactor at National Tsing Hua University in Hsinchu, Taiwan. The stamp and envelope feature several illustrations of the reactor, which was completed on April…

Cachet depicts Alfred Nobel, while stamps depict the 1901 Nobel Prize winners.

Romanian postage stamp issued in 1960 featuring an illustration of a nuclear reactor.

Soviet Union postage stamp commemorating the First Congress of the International Federation of Automatic Control (IFAC), which first took place in Moscow, Russia. The stamp features the Tower of the University of Moscow…

Cachet and stamp depict Johan Gadolin, who discovered the element yttrium and is considered the "founder of Finnish chemistry." The stamp commemorates the bicentennial of Gadolin's birth and features his likeness based…

Postage stamp from the German Democratic Republic (East Germany), commemorating the 250th anniversary of the German Academy of Sciences in Berlin. The stamp features a portrait of Hermann von Helmholtz (1821-1894), a…

Cachet and stamp depict the Swedish chemist and physicist Svante Arrhenius.

Depicts three 19th-century silver miners.

Stamp depicts measuring instruments.

Cachet and stamp depict oil pipeline and drilling derricks.

First day cover commemorating the 175th anniversary of École des Mines de Paris (National Superior School of Mines), also known as Mines Paris.

Six East German postage stamps commemorating physicist and Nobel Prize Winner Max Planck (1858-1947). The red and green stamps are to celebrate the birth of Planck. The purple stamp is part of a series honoring…

Postcard depicting the Atomium monument from the 1958 World's Fair exhibition in Brussels, Belgium. Designed by engineer André Waterkeyn (1917-2005) and architects André (1914-1988) and Jean Polak (1920-2012), the…

Peruvian postage stamp commemorating the centenary of the birth of Daniel Alcides Carrión García (1857-1885), a Peruvian medical student after whom Carrion's disease is named. The stamp depicts Saint Martin de Porres…

Mexican postage stamp issued to commemorate the 20th anniversary of the nationalization of all petroleum reserves, facilities, and foreign oil companies in Mexico and the establishment of the state-owned petroleum…

Mexican postage stamp issued to commemorate the 20th anniversary of the nationalization of all petroleum reserves, facilities, and foreign oil companies in Mexico and the establishment of the state-owned petroleum…

Mexican postage stamp issued to commemorate the 20th anniversary of the nationalization of all petroleum reserves, facilities, and foreign oil companies in Mexico and the establishment of the state-owned petroleum…

Mexican postage stamp issued to commemorate the 20th anniversary of the nationalization of all petroleum reserves, facilities, and foreign oil companies in Mexico and the establishment of the state-owned petroleum…