Potassium superoxide
Encyclopedia
Potassium superoxide is the chemical compound
with the formula KO2. This rare salt of the superoxide
ion
is produced by burning molten potassium in pure oxygen
. Potassium superoxide is used as an oxidizing agent in industrial chemistry, as a CO2
scrubber, H2O
dehumidifier and O2
generator in rebreather
s, spacecraft
, submarines and spacesuit life support system
s.
Important reactions:
The Russian Space Agency has had success using potassium superoxide in chemical oxygen generator
s for its spacesuits and Soyuz spacecraft
. KO2 has also been utilized in canisters for rebreathers for fire fighting
and mine rescue work, but had limited use in scuba
rebreathers because of the dangers of explosive reaction with water. The theoretical capacity of KO2 is the absorption of 0.309 kg CO2 per kg of absorbent while 0.38 kg O2 are generated per kg of absorbent. The human body though will produce more CO2 than oxygen absorbed, thus a device or absorbent specifically for CO2 scrubbing may also be required.
of the O-O bond.
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
with the formula KO2. This rare salt of the superoxide
Superoxide
A superoxide, also known by the obsolete name hyperoxide, is a compound that possesses the superoxide anion with the chemical formula O2−. The systematic name of the anion is dioxide. It is important as the product of the one-electron reduction of dioxygen O2, which occurs widely in nature...
ion
Ion
An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...
is produced by burning molten potassium in pure oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
. Potassium superoxide is used as an oxidizing agent in industrial chemistry, as a CO2
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
scrubber, H2O
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
dehumidifier and O2
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
generator in rebreather
Rebreather
A rebreather is a type of breathing set that provides a breathing gas containing oxygen and recycled exhaled gas. This recycling reduces the volume of breathing gas used, making a rebreather lighter and more compact than an open-circuit breathing set for the same duration in environments where...
s, spacecraft
Spacecraft
A spacecraft or spaceship is a craft or machine designed for spaceflight. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and transportation of humans and cargo....
, submarines and spacesuit life support system
Life support system
In human spaceflight, a life support system is a group of devices that allow a human being to survive in space.US government space agency NASA,and private spaceflight companies...
s.
Important reactions:
- 4 KO2 + 2 H2O → 4 KOH + 3 O2
- 2 KOH + CO2 → K2CO3 + H2O
- K2CO3 + CO2 + H2O → 2 KHCO3
The Russian Space Agency has had success using potassium superoxide in chemical oxygen generator
Chemical oxygen generator
A chemical oxygen generator is a device releasing oxygen created by a chemical reaction. The oxygen source is usually an inorganic superoxide, chlorate, or perchlorate. A promising group of oxygen sources are ozonides. The generators are usually ignited mechanically, by a firing pin, and the...
s for its spacesuits and Soyuz spacecraft
Soyuz spacecraft
Soyuz , Union) is a series of spacecraft initially designed for the Soviet space programme by the Korolyov Design Bureau in the 1960s, and still in service today...
. KO2 has also been utilized in canisters for rebreathers for fire fighting
Fire fighting
Firefighting is the act of extinguishing fires. A firefighter fights fires to prevent loss of life, and/or destruction of property and the environment...
and mine rescue work, but had limited use in scuba
Scuba set
A scuba set is an independent breathing set that provides a scuba diver with the breathing gas necessary to breathe underwater during scuba diving. It is much used for sport diving and some sorts of work diving....
rebreathers because of the dangers of explosive reaction with water. The theoretical capacity of KO2 is the absorption of 0.309 kg CO2 per kg of absorbent while 0.38 kg O2 are generated per kg of absorbent. The human body though will produce more CO2 than oxygen absorbed, thus a device or absorbent specifically for CO2 scrubbing may also be required.
Structural trends in dioxygen compounds
The derivatives of dioxygen, O2, have characteristic O-O distances that correlate with the bond orderBond order
Bond order is the number of chemical bonds between a pair of atoms. For example, in diatomic nitrogen N≡N the bond order is 3, while in acetylene H−C≡C−H the bond order between the two carbon atoms is also 3, and the C−H bond order is 1. Bond order gives an indication to the stability of a bond....
of the O-O bond.
| Dioxygen compound | name | O-O distance in Å | O-O bond order |
|---|---|---|---|
| O2+ | dioxygenyl Dioxygenyl The dioxygenyl ion, O2+, is a rarely encountered oxycation in which both oxygen atoms have a formal oxidation state of +½. It is formally derived from oxygen by the removal of an electron:... cation |
1.12 | 2.5 |
| O2 | dioxygen Oxygen Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition... |
1.21 | 2 |
| O2- | superoxide Superoxide A superoxide, also known by the obsolete name hyperoxide, is a compound that possesses the superoxide anion with the chemical formula O2−. The systematic name of the anion is dioxide. It is important as the product of the one-electron reduction of dioxygen O2, which occurs widely in nature... |
1.28 | 1.5 |
| O22- | peroxide Peroxide A peroxide is a compound containing an oxygen–oxygen single bond or the peroxide anion .The O−O group is called the peroxide group or peroxo group. In contrast to oxide ions, the oxygen atoms in the peroxide ion have an oxidation state of −1.The simplest stable peroxide is hydrogen peroxide... |
1.49 | 1 |