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Naturally occurring oxygen is composed of three stable isotopes, 16 O, 17 O, and 18 O, with 16 O being the most abundant (99.762% natural abundance). [ 60 ] Most 16 O is synthesized at the end of the helium fusion process in massive stars but some is made in the neon burning process .
Solid oxygen forms at normal atmospheric pressure at a temperature below 54.36 K (−218.79 °C, −361.82 °F). Solid oxygen O 2 , like liquid oxygen , is a clear substance with a light sky-blue color caused by absorption in the red part of the visible light spectrum.
Photosynthetic prokaryotic organisms that produced O 2 as a byproduct lived long before the first build-up of free oxygen in the atmosphere, [5] perhaps as early as 3.5 billion years ago. The oxygen cyanobacteria produced would have been rapidly removed from the oceans by weathering of reducing minerals, [citation needed] most notably ferrous ...
Other important organic compounds that contain oxygen are: glycerol, formaldehyde, glutaraldehyde, citric acid, acetic anhydride, acetamide, etc. Epoxides are ethers in which the oxygen atom is part of a ring of three atoms. Oxygen reacts spontaneously with many organic compounds at or below room temperature in a process called autoxidation. [7]
There are several known allotropes of oxygen. The most familiar is molecular oxygen (O 2), present at significant levels in Earth's atmosphere and also known as dioxygen or triplet oxygen. Another is the highly reactive ozone (O 3). Others are: Atomic oxygen (O 1), a free radical. Singlet oxygen (O * 2), one of two metastable states of ...
The light elements sulfur, silicon, oxygen, carbon, and hydrogen may constitute part of the outer core due to their abundance and ability to partition into liquid iron under certain conditions. The depletion of siderophile elements in Earth's mantle compared to chondritic meteorites is attributed to metal-silicate reactions during formation of ...
Wolfgang Puck may be one of the biggest chefs in the world—known for his wide-ranging culinary creations such as his Chinese chicken salad and pizzas—but did you know that Wolfgang Puck still ...
The Great Oxidation Event (GOE) or Great Oxygenation Event, also called the Oxygen Catastrophe, Oxygen Revolution, Oxygen Crisis or Oxygen Holocaust, [2] was a time interval during the Earth's Paleoproterozoic era when the Earth's atmosphere and shallow seas first experienced a rise in the concentration of free oxygen. [3]