Carbon monoxide is a colorless and tasteless flammable gas, less dense than air. It is toxic to animals that use hemoglobin as an oxygen carrier when encountered in concentrations above about 35 ppm, although it is produced in normal animal metabolism in low quantities, is thought to have some normal biological functions. In the atmosphere, it is spatially variable and short lived, having a role in the formation of ground-level ozone. Carbon monoxide consists of one carbon atom and one oxygen atom, connected by a triple bond that consists of a net two pi bonds and one sigma bond, it is the simplest oxocarbon and is isoelectronic with other triply-bonded diatomic molecules having ten valence electrons, including the cyanide anion, the nitrosonium cation and molecular nitrogen. In coordination complexes the carbon monoxide ligand is called carbonyl. Aristotle first recorded. An ancient method of execution was to shut the criminal in a bathing room with smoldering coals. What was not known was the mechanism of death.
Greek physician Galen speculated that there was a change in the composition of the air that caused harm when inhaled. In 1776, the French chemist de Lassone produced CO by heating zinc oxide with coke, but mistakenly concluded that the gaseous product was hydrogen, as it burned with a blue flame; the gas was identified as a compound containing carbon and oxygen by the Scottish chemist William Cruickshank in 1800. Its toxic properties on dogs were investigated by Claude Bernard around 1846. During World War II, a gas mixture including carbon monoxide was used to keep motor vehicles running in parts of the world where gasoline and diesel fuel were scarce. External charcoal or wood gas generators were fitted, the mixture of atmospheric nitrogen, carbon monoxide, small amounts of other gases produced by gasification was piped to a gas mixer; the gas mixture produced by this process is known as wood gas. Carbon monoxide was used on a large scale during the Holocaust at some Nazi German extermination camps, the most notable by gas vans in Chełmno, in the Action T4 "euthanasia" program.
Carbon monoxide is produced from the partial oxidation of carbon-containing compounds. In the presence of oxygen, including atmospheric concentrations, carbon monoxide burns with a blue flame, producing carbon dioxide. Coal gas, used before the 1960s for domestic lighting and heating, had carbon monoxide as a significant fuel constituent; some processes in modern technology, such as iron smelting, still produce carbon monoxide as a byproduct. A large quantity of CO byproduct is formed during the oxidative processes for the production of chemicals. For this reason, the process off-gases have to be purified. On the other hand, considerable research efforts are made in order to optimize the process conditions, develop catalyst with improved selectivity and to understand the reaction pathways leading to the target product and side products. Worldwide, the largest source of carbon monoxide is natural in origin, due to photochemical reactions in the troposphere that generate about 5×1012 kilograms per year.
Other natural sources of CO include volcanoes, forest fires, other forms of combustion, carbon monoxide-releasing molecules. In biology, carbon monoxide is produced by the action of heme oxygenase 1 and 2 on the heme from hemoglobin breakdown; this process produces a certain amount of carboxyhemoglobin in normal persons if they do not breathe any carbon monoxide. Following the first report that carbon monoxide is a normal neurotransmitter in 1993, as well as one of three gases that modulate inflammatory responses in the body, carbon monoxide has received a great deal of clinical attention as a biological regulator. In many tissues, all three gases are known to act as anti-inflammatories and promoters of neovascular growth. Clinical trials of small amounts of carbon monoxide. Too much carbon monoxide causes carbon monoxide poisoning. Carbon monoxide has a molar mass of 28.0, according to the ideal gas law, makes it less dense than air, whose average molar mass is 28.8. The bond length between the carbon atom and the oxygen atom is 112.8 pm.
This bond length is consistent with a triple bond, as in molecular nitrogen, which has a similar bond length and nearly the same molecular mass. Carbon–oxygen double bonds are longer, 120.8 pm in formaldehyde, for example. The boiling point and melting point are similar to those of N2; the bond-dissociation energy of 1072 kJ/mol is stronger than that of N2 and represents the strongest chemical bond known. The ground electronic state of carbon monoxide is a singlet state since there are no unpaired electrons. Carbon and oxygen together have a total of 10 electrons in the valence shell. Following the octet rule for both carbon and oxygen, the two atoms form a triple bond, with six shared electrons in three bonding molecular orbitals, rather than the usual double bond found in organic carbonyl compounds. Since four of the shared electrons come from the oxygen atom and only two from carbon, one bonding orbital is occupied by two electrons from oxygen, forming a dative or dipolar bond; this causes a C←O polarization of the molecule, with a small negative charge on carbon and a small positive charge on oxygen.
The other two bonding orbitals are each occupied by one e
Stenochlaena palustris is an edible medicinal fern species. In the folk medicines of India and Malaysia, the leaves of this fern are used as remedies for fever, skin diseases and stomachache; this plant is a long-climbing fern with thin black scales and stems that can reach up to 20 m. It has pinnate fronds that are 30–100 cm long, petioles that are 7–20 cm long, ovate lanceolate pinnae that are 10–15 cm long and 1.5–4.5 cm wide. The fern's sporophylls are long and narrow, have brownish sori undernwath. Acylated flavonol glycosides isolated from the fern were found to have antibacterial activities. Crude and purified extracts prepared from the fern have been shown to exhibit antifungal and antiglucosidase activities; the district of Diliman in Quezon City, one of the Philippines' most important educational districts, is named after this fern. The species epithet palustris is Latin for "of the marsh" and indicates its common habitat. In the Malaysian state of Sarawak, the plant is called "Midin".
Group Captain Basil Vernon Robinson DSO DFC & bar AFC was a pilot with RAF Bomber Command during World War II. He is most notable for flying a Handley Page Halifax bomber over 500 miles back to England and safely landing it after the other six crew members had bailed out. Robinson was born in Gateshead and Wear and was a keen rugby player, he was commissioned into the RAF in 1933 and joined No. 35 Squadron RAF in 1941 after completing a tour of duty as a pilot on Whitley bombers. On 18 December 1941 he was involved in an air raid on German battleships Scharnhorst and Gneisenau and was awarded the DFC for his actions. In March 1942 he was appointed commander of 35 Squadron. On the night of 18/19 November 1942 after a raid on Turin, Italy a target indicator flare left hanging in the 22 ft long bomb bay of Robinson's aircraft burst into flames whilst he was flying over the Alps, he ordered the crew to bail out and stayed at the controls whilst they did so to maintain level flight. However, by the time they had all jumped.
He therefore decided to attempt to fly the large aircraft back to England over hostile territory without a navigator, flight engineer, wireless operator or air gunners. He was subsequently appointed the station commander at RAF Graveley, he died on the night of 23/24 August 1943 near Wensickendorf, Germany when his Halifax HR928 was shot down by a nightfighter during a raid on Berlin. He is buried in the Berlin 1939-45 war cemetery