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  2. Water splitting - Wikipedia

    en.wikipedia.org/wiki/Water_splitting

    In thermolysis, water molecules split into hydrogen and oxygen. For example, at 2,200 °C (2,470 K; 3,990 °F) about three percent of all H 2 O are dissociated into various combinations of hydrogen and oxygen atoms, mostly H, H 2, O, O 2, and OH. Other reaction products like H 2 O 2 or HO 2 remain minor. At the very high temperature of 3,000 ...

  3. Hydrogen cycle - Wikipedia

    en.wikipedia.org/wiki/Hydrogen_cycle

    The hydrogen cycle consists of hydrogen exchanges between biotic (living) and abiotic (non-living) sources and sinks of hydrogen-containing compounds. Hydrogen (H) is the most abundant element in the universe. [1] On Earth, common H-containing inorganic molecules include water (H 2 O), hydrogen gas (H 2), hydrogen sulfide (H 2 S), and ammonia ...

  4. Hydroxyl radical - Wikipedia

    en.wikipedia.org/wiki/Hydroxyl_radical

    Most notably hydroxyl radicals are produced from the decomposition of hydroperoxides (ROOH) or, in atmospheric chemistry, by the reaction of excited atomic oxygen with water. It is also an important radical formed in radiation chemistry, since it leads to the formation of hydrogen peroxide and oxygen , which can enhance corrosion and stress ...

  5. Autoxidation - Wikipedia

    en.wikipedia.org/wiki/Autoxidation

    It is also an important concept in both industrial chemistry and biology. [4] Autoxidation is therefore a fairly broad term and can encompass examples of photooxygenation and catalytic oxidation . The common mechanism is a free radical chain reaction , where the addition of oxygen gives rise to hydroperoxides and their associated peroxy ...

  6. Oxygen evolution - Wikipedia

    en.wikipedia.org/wiki/Oxygen_evolution

    Oxygen evolution is the chemical process of generating elemental diatomic oxygen (O 2) by a chemical reaction, usually from water, the most abundant oxide compound in the universe. Oxygen evolution on Earth is effected by biotic oxygenic photosynthesis , photodissociation , hydroelectrolysis , and thermal decomposition of various oxides and ...

  7. Reactive oxygen species - Wikipedia

    en.wikipedia.org/wiki/Reactive_oxygen_species

    In chemistry and biology, reactive oxygen species (ROS) are highly reactive chemicals formed from diatomic oxygen (O 2), water, and hydrogen peroxide. Some prominent ROS are hydroperoxide (O 2 H), superoxide (O 2 −), [1] hydroxyl radical (OH.), and singlet oxygen. [2] ROS are pervasive because they are readily produced from O 2, which is ...

  8. Hydroperoxyl - Wikipedia

    en.wikipedia.org/wiki/Hydroperoxyl

    Together with its conjugate base superoxide, hydroperoxyl is an important reactive oxygen species.Unlike • O − 2, which has reducing properties, HO • 2 can act as an oxidant in a number of biologically important reactions, such as the abstraction of hydrogen atoms from tocopherol and polyunstaturated fatty acids in the lipid bilayer.

  9. Dioxygen in biological reactions - Wikipedia

    en.wikipedia.org/wiki/Dioxygen_in_biological...

    After being carried in blood to a body tissue in need of oxygen, O 2 is handed off from the heme group to monooxygenase, an enzyme that also has an active site with an atom of iron. [9] Monooxygenase uses oxygen for many oxidation reactions in the body. Oxygen that is suspended in the blood plasma equalizes into the tissue according to Henry's law.