Search results
Results from the WOW.Com Content Network
Oxygen is the third most abundant chemical element in the universe, after hydrogen and helium. [68] About 0.9% of the Sun's mass is oxygen. [19] Oxygen constitutes 49.2% of the Earth's crust by mass [69] as part of oxide compounds such as silicon dioxide and is the most abundant element by mass in the Earth's crust.
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 ...
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.
Compounds containing oxygen in other oxidation states are very uncommon: − 1 ⁄ 2 (superoxides), − 1 ⁄ 3 , 0 (elemental, hypofluorous acid), + 1 ⁄ 2 , +1 (dioxygen difluoride), and +2 (oxygen difluoride). Oxygen is reactive and will form oxides with all other elements except the noble gases helium, neon, argon and krypton. [1]
Liquid oxygen has a clear cyan color and is strongly paramagnetic: it can be suspended between the poles of a powerful horseshoe magnet. [2] Liquid oxygen has a density of 1.141 kg/L (1.141 g/ml), slightly denser than liquid water, and is cryogenic with a freezing point of 54.36 K (−218.79 °C; −361.82 °F) and a boiling point of 90.19 K (−182.96 °C; −297.33 °F) at 1 bar (14.5 psi).
The lower, O 2 (1 Δ g) state is commonly referred to as singlet oxygen. The energy difference of 94.3 kJ/mol between ground state and singlet oxygen corresponds to a forbidden singlet-triplet transition in the near-infrared at ~1270 nm. [12]
Chili Crisp Fried Tofu. Chili crisp is the MVP in the flavor bomb pantry, and it’s back to prove it again with this chili crisp fried tofu.Featuring a vibrant spicy-sweet sauce made with just ...
Tetraoxygen was first predicted in 1924 by Gilbert N. Lewis, who proposed it as an explanation for the failure of liquid oxygen to obey Curie's law. [1] Though not entirely inaccurate, computer simulations indicate that although there are no stable O 4 molecules in liquid oxygen, O 2 molecules do tend to associate in pairs with antiparallel spins, forming transient O 4 units. [2]