Gallium
Gallium is a soft, silvery chemical element with atomic number 31. It melts at about 29.8 °C and is used in semiconductor compounds and alloys.
Periodic table: A tabular arrangement of chemical elements by atomic number and recurring chemical properties. Gallium occupies group 13, period 4, among elements with three valence electrons.
Gallium arsenide: A compound semiconductor made from gallium and arsenic, used in high-speed electronics and optoelectronics. It is a major technology built from gallium, with properties distinct from the pure element.
Light-emitting diode: A semiconductor device that emits light when electric current passes through it. Gallium nitride and related compounds underpin many modern blue and white LEDs.
Dmitri Mendeleev: A Russian chemist who formulated the periodic table and predicted properties of undiscovered elements. Mendeleev predicted an element below aluminum whose properties closely matched gallium.
Aluminum: A lightweight metallic element with atomic number 13, widely used in structures and packaging. Gallium sits below aluminum in group 13 but melts at a far lower temperature.
Chemical element: A pure substance whose atoms have the same number of protons in their nuclei. Gallium is defined by its 31 protons, regardless of its isotope or chemical form.
Gallium nitride: A wide-bandgap semiconductor composed of gallium and nitrogen, used in LEDs and power electronics. Its robust electronic properties make it one of gallium’s most consequential compound forms.
Radio-frequency semiconductor device: An electronic component that generates, amplifies, or switches signals at radio frequencies. Gallium arsenide and gallium nitride support fast, high-frequency components.
Paul-Émile Lecoq de Boisbaudran: A French chemist who discovered gallium by spectroscopy in 1875. He isolated and identified gallium, confirming the element’s existence.
Indium: A soft, silvery metallic element with atomic number 49, used in electronics and alloys. Indium is gallium’s heavier group neighbor and forms low-melting alloys with it.