Gas dioxide, and air expand to the same extent over the same 80 kelvin interval. He noted that, for an ideal gas at constant pressure, the volume is directly proportional to its temperature: In 1802, Joseph Louis Gay-Lussac published results of similar, though more extensive experiments. Gay-Lussac credited Charles' earlier work by naming the law in his honor. Gay-Lussac himself is credited with the law describing pressure, which he found in 1809. It states that the pressure exerted on a container's sides by an ideal gas is proportional to its temperature. In 1811, Amedeo Avogadro verified that equal volumes of pure
Industrial gas since all isotopes are radiogenic nuclides from radioactive decay. (It is not known if any synthetic elements with atomic number above 108 are gases.) The elements which are stable two atom homonuclear molecules at standard temperature and pressure (STP), are hydrogen (H), nitrogen (N) and oxygen (O), plus the halogens fluorine (F) and chlorine (Cl). The noble gases are all monatomic. In the industrial gases industry the term "elemental gases" (or sometimes less accurately "molecular gases") is used to distinguish these gases from molecules that are also chemical compounds. These elements are all nonmetals. Radon is chemically stable, but it