dioksigen

Dioksigen, or dioxygen, is the diatomic molecule with chemical formula O2. It is a colorless, odorless, tasteless gas at room temperature and standard pressure, and it makes up about 21 percent of the Earth’s atmosphere. O2 is essential for aerobic respiration in many organisms and serves as the final electron acceptor in cellular energy production. The molecule consists of two oxygen atoms linked by a double bond. It has a bond length of about 121 picometres and a bond dissociation energy near 498 kJ/mol. Its ground state is a triplet, which renders it paramagnetic.

Biological and industrial cycles sustain dioksigen levels. It is produced by photosynthesis in plants, algae, and some bacteria, releasing O2 as a byproduct. It is consumed during respiration, decay, and combustion. Industrially, oxygen is obtained primarily by fractionally distilling liquefied air, but also through methods such as pressure swing adsorption, electrolysis of water, or certain membrane separations. Oxygen is widely used in steelmaking, welding, medical therapies, and chemical synthesis, and it supports combustion in many industrial processes.

Safety and isotopes are notable considerations. Although dioksigen itself is not flammable, it supports and accelerates burning, so higher concentrations require careful handling and ventilation. The most abundant isotope is 16O; smaller amounts of 17O and 18O occur naturally and are used in scientific studies.

Historically, oxygen was identified in the 1770s by researchers such as Priestley and Scheele, with Lavoisier contributing to its naming and recognition as a distinct element. Today, dioksigen remains a fundamental component of life and industry.