Wasserstoffs

Wasserstoffs, commonly known as hydrogen, is the chemical element with symbol H and atomic number 1. It is the lightest element and the most abundant chemical species in the universe, found mainly in stars and gas giant planets. On Earth, hydrogen exists primarily in compounds such as water and hydrocarbons; free H2 gas is relatively scarce in the atmosphere but can be produced economically for industrial use.

Hydrogen is a diatomic molecule (H2) at standard conditions, colorless, odorless, and tasteless. It has a very low boiling and melting point, making it a cryogenic liquid at -252.8 C. Hydrogen is a highly flammable reducing agent; it forms explosive mixtures with air and requires careful handling. When burned, it primarily forms water, contributing to its appeal as an energy carrier.

Hydrogen occurs naturally in various isotopic forms, with protium and deuterium as common stable isotopes and tritium as a radioactive one. It is produced commercially mainly by steam methane reforming, water electrolysis, and other chemical processes. Recovered hydrogen is also produced during petroleum refining and ammonia synthesis.

Hydrogen is a key industrial feedstock for ammonia production via the Haber process, for refining and hydrogenation reactions, and as a fuel and energy carrier in fuel cells and combustion engines. In rocketry, liquid hydrogen is used with liquid oxygen as a high-efficiency rocket propellant. Hydrogen also serves as a potential energy vector in a future low-carbon economy.

Hydrogen is stored as a compressed gas or as a cryogenic liquid, with safety concerns including flammability, low density by volume, embrittlement of certain metals, and the need for leak detection and proper ventilation.

Hydrogen was identified as a distinct element in 1766 by Henry Cavendish, who described it as “inflammable air” produced from acids. The name hydrogen comes from the Greek hydro- meaning "water" and -genes meaning "generator."