Oxygen

Oxygen is a chemical element; it has the symbolO and its atomic number is8. It is a member of the chalcogen group in the periodic table. It is highly reactive, a nonmetal, and a potent oxidizing agent that readily forms oxides with most elements as well as with other compounds. Oxygen is the most abundant element in Earth's crust, making up almost half of the Earth's crust in the form of various oxides such as water, carbon dioxide, iron oxides, and silicates. It is also the third-most abundant element in the universe after hydrogen and helium.

condition in which the body or a region of the body is deprived of adequate oxygen supply at the tissue level

one of the physical forms of elemental oxygen

set of fusion reactions by which stars convert hydrogen to helium: 4¹H+2e⁻→⁴He+2e⁺+2e⁻+2νₑ+3γ+24.7 MeV→⁴He+2νₑ+3γ+26.7 MeV

Paleoproterozoic surge in atmospheric oxygen

metalworking technique using a gaseous fuel and oxygen

condition resulting from the harmful effects of breathing molecular oxygen at increased partial pressures

thumb|right|Nineteenth-century electrolytic cell for producing oxyhydrogen Oxyhydrogen is a mixture of hydrogen (H2) and oxygen (O2) gases. This gaseous mixture is used for torches to process refractory materials and was the first

fraction of oxygen-saturated hemoglobin relative to total hemoglobin in the blood

biogeochemical cycle of oxygen within its four main reservoirs: the atmosphere, the biosphere, the hydrosphere, and the lithosphere

type of isotope that has 8 protons

intervals in the Earth's past

oxygen production experiment on the Perseverance rover

low environmental oxygen levels

relative measure of the amount of oxygen that is dissolved or carried in a given medium

thumb|right|Cat's Eye Nebula (NGC 6543) thumb|Cat's Eye Nebula (NGC 6543) Nebulium was a proposed element found in astronomical observation of a nebula by William Huggins in 1864. The strong green emission lines of the Cat's Eye Nebula, discovered using spectroscopy, led to the postulation that an as yet unknown element was responsible for this emission. In 1927, Ira Sprague Bowen showed that the lines are emitted by doubly ionized oxygen (new style O; old style O), and no new element was necessary to explain them.

biogeochemical cycle

oxygen produced in obscurity

The dioxygenyl ion, , has been studied in both the gas phase and in salts with anions that cannot be oxidized. The first synthesis was []. Rather than the double bond of , the bond order is considered to be . Relative to most molecules, this ionization energy is very high at 1175 kJ/mol. As a result, the scope of the chemistry of is quite limited, acting mainly as a 1-electron oxidiser.

deprivation of oxygen to the brain

oxygen in a solid state

different chemical forms of elemental oxygen

establishment that sells oxygen for on-site recreational use

gas mixture used as anesthetic and for pain relief

storage vessel for oxygen

timeline of the development of free oxygen in the Earth's seas and atmosphere

device that releases oxygen via a chemical reaction

uncrewed orbital fuel station

test to determine concentration of dissolved oxygen in water

Hyperoxia is the state of being exposed to high levels of oxygen; it may refer to organisms, cells and tissues that are experiencing excessive oxygenation, or to an abnormally high oxygen concentration in an environment (e.g. a body of water).

S-shaped curve produced when the percentage saturation of haemoglobin with oxygen is plotted against the partial pressure of oxygen (pO2), which is a measure of the oxygen concentration in the surrounding medium

the process of generating molecular oxygen through chemical reaction

chemical process

oxygen dication

expansion of oxygen minimum zones in oceans

apparatus which controls the amount of oxygen in an enclosed package

type of beverage enriched in gaseous oxygen

thumb|Finger tip carboxyhemoglobin saturation monitor.|alt=NOTE I would suggest that this article use as its example device a standalone CO-oximeter. Use the blood-gas-attached and 'peripheral' devices as alternative devices. A pulse CO-oximeter is a non-invasive, multi-wavelength instrument that measures the oxygen carrying state of hemoglobin in a blood specimen, including oxygen-carrying hemoglobin (O2Hb), non-oxygen-carrying but normal hemoglobin (HHb) as well as the dyshemoglobins such as carboxyhemoglobin (COHb) and methemoglobin (MetHb). Pulse CO-oximeters use four or more wavelengths w

book by Joseph Priestley

device which produces a voltage by a chemical reaction with oxygen proportional to partial pressure

cyclical variations in the ratio of the abundance of oxygen

level of oxygen (about 0.3% by volume) above which facultative aerobic microorganisms and facultative anaerobes adapt from fermentation to aerobic respiration