Cyclosarin
Encyclopedia
Cyclosarin or GF is an extremely toxic
substance used as a chemical weapon. It is a member of the G-series family of nerve agent
s, a group of chemical weapons
discovered and synthesized by a German
team led by Dr. Gerhard Schrader
. The major nerve gases are the G agents, sarin
(GB), soman
, tabun
, and the V agents such as VX
. The original agent, tabun, was discovered in Germany in 1936 in the process of work on organophosphorus
insecticide
s. Next came sarin, soman and finally the most toxic, VX, a product of commercial insecticide laboratories prior to World War II
.
As a chemical weapon
, it is classified as a weapon of mass destruction by the United Nations
, according to UN Resolution 687, and its production and stockpiling was outlawed by the Chemical Weapons Convention
of 1993.
nerve agent. Its physical characteristics are, however, quite different from sarin.
At room temperature
, cyclosarin is a colorless liquid whose odor has been variously described as sweet and musty, or resembling peach
es or shellac
. Unlike sarin, cyclosarin is a persistent liquid, meaning that it has a low vapor pressure
and therefore evaporates
relatively slowly, about 69 times slower than sarin and 20 times slower than water.
Also unlike sarin, cyclosarin is flammable
, with a flash point
of 94 °C (201 °F).
Cyclosarin (GF) also demonstrates greater toxicity than sarin (GB) in humans. Sarin has a median lethal dose (LD50) of 5 mg (for a 70 kg human), while GF has an LD50 of 1.2 mg. The median lethal concentration and time (LCt50) of cyclosarin is 50 mg⋅min/m3, which is half that of GB.
as part of Germany
's chemical weapons research on organophosphate compounds after their military potential was discovered, cyclosarin was also studied later in the United States
and Great Britain
in the early 1950s
as part of a systematic study of potential nerve agents. It was never selected for mass production, however, due to its precursors being more expensive than those of other G-series nerve agents such as sarin (GB).
To date, Iraq is the only nation known to have manufactured significant quantities of cyclosarin for use as a chemical agent and to actually deploy it in battle. During the Iran-Iraq war
(1986–1988) the Iraqis used sarin and cyclosarin together as a mixture. This was likely done to obtain a more persistent chemical agent as well as in response to an existing embargo placed on alcohol precursors for sarin.
A cyclosarin binary weapon would most likely contain methylphosphonyl difluoride
in one capsule, with the other capsule containing either cyclohexanol
or a mixture of cyclohexylamine
and cyclohexanol.
fielded munitions filled with a mixture of GB (sarin) and GF (cyclosarin). Tests on mice indicated that GB-GF mixtures have a relative toxicity between GF and GB.
Toxicity
Toxicity is the degree to which a substance can damage a living or non-living organisms. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism, such as a cell or an organ , such as the liver...
substance used as a chemical weapon. It is a member of the G-series family of nerve agent
Nerve agent
Nerve agents are a class of phosphorus-containing organic chemicals that disrupt the mechanism by which nerves transfer messages to organs...
s, a group of chemical weapons
Chemical warfare
Chemical warfare involves using the toxic properties of chemical substances as weapons. This type of warfare is distinct from Nuclear warfare and Biological warfare, which together make up NBC, the military acronym for Nuclear, Biological, and Chemical...
discovered and synthesized by a German
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
team led by Dr. Gerhard Schrader
Gerhard Schrader
Dr. Gerhard Schrader was a German chemist specializing in the discovery of new insecticides, hoping to make progress in the fight against hunger in the world. However, Dr...
. The major nerve gases are the G agents, sarin
Sarin
Sarin, or GB, is an organophosphorus compound with the formula [2CHO]CH3PF. It is a colorless, odorless liquid, which is used as a chemical weapon. It has been classified as a weapon of mass destruction in UN Resolution 687...
(GB), soman
Soman
Soman, or GD , is an extremely toxic chemical substance. It is a nerve agent, interfering with normal functioning of the mammalian nervous system by inhibiting the cholinesterase enzyme. As a chemical weapon, it is classified as a weapon of mass destruction by the United Nations according to UN...
, tabun
Tabun (nerve agent)
Tabun or GA is an extremely toxic chemical substance. It is a clear, colorless, and tasteless liquid with a faint fruity odor. It is classified as a nerve agent because it fatally interferes with normal functioning of the mammalian nervous system...
, and the V agents such as VX
VX (nerve agent)
VX, IUPAC name O-ethyl S-[2-ethyl] methylphosphonothioate, is an extremely toxic substance whose only application is in chemical warfare as a nerve agent. As a chemical weapon, it is classified as a weapon of mass destruction by the United Nations in UN Resolution 687...
. The original agent, tabun, was discovered in Germany in 1936 in the process of work on organophosphorus
Organophosphorus
Organophosphorus compounds are degradable organic compounds containing carbon–phosphorus bonds , used primarily in pest control as an alternative to chlorinated hydrocarbons that persist in the environment...
insecticide
Insecticide
An insecticide is a pesticide used against insects. They include ovicides and larvicides used against the eggs and larvae of insects respectively. Insecticides are used in agriculture, medicine, industry and the household. The use of insecticides is believed to be one of the major factors behind...
s. Next came sarin, soman and finally the most toxic, VX, a product of commercial insecticide laboratories prior to World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
.
As a chemical weapon
Chemical warfare
Chemical warfare involves using the toxic properties of chemical substances as weapons. This type of warfare is distinct from Nuclear warfare and Biological warfare, which together make up NBC, the military acronym for Nuclear, Biological, and Chemical...
, it is classified as a weapon of mass destruction by the United Nations
United Nations
The United Nations is an international organization whose stated aims are facilitating cooperation in international law, international security, economic development, social progress, human rights, and achievement of world peace...
, according to UN Resolution 687, and its production and stockpiling was outlawed by the Chemical Weapons Convention
Chemical Weapons Convention
The Chemical Weapons Convention is an arms control agreement which outlaws the production, stockpiling and use of chemical weapons. Its full name is the Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on their Destruction...
of 1993.
Chemical characteristics
Like its predecessor sarin, cyclosarin is a liquid organophosphateOrganophosphate
An organophosphate is the general name for esters of phosphoric acid. Phosphates are probably the most pervasive organophosphorus compounds. Many of the most important biochemicals are organophosphates, including DNA and RNA as well as many cofactors that are essential for life...
nerve agent. Its physical characteristics are, however, quite different from sarin.
At room temperature
Room temperature
-Comfort levels:The American Society of Heating, Refrigerating and Air-Conditioning Engineers has listings for suggested temperatures and air flow rates in different types of buildings and different environmental circumstances. For example, a single office in a building has an occupancy ratio per...
, cyclosarin is a colorless liquid whose odor has been variously described as sweet and musty, or resembling peach
Peach
The peach tree is a deciduous tree growing to tall and 6 in. in diameter, belonging to the subfamily Prunoideae of the family Rosaceae. It bears an edible juicy fruit called a peach...
es or shellac
Shellac
Shellac is a resin secreted by the female lac bug, on trees in the forests of India and Thailand. It is processed and sold as dry flakes , which are dissolved in ethyl alcohol to make liquid shellac, which is used as a brush-on colorant, food glaze and wood finish...
. Unlike sarin, cyclosarin is a persistent liquid, meaning that it has a low vapor pressure
Vapor pressure
Vapor pressure or equilibrium vapor pressure is the pressure of a vapor in thermodynamic equilibrium with its condensed phases in a closed system. All liquids have a tendency to evaporate, and some solids can sublimate into a gaseous form...
and therefore evaporates
Evaporation
Evaporation is a type of vaporization of a liquid that occurs only on the surface of a liquid. The other type of vaporization is boiling, which, instead, occurs on the entire mass of the liquid....
relatively slowly, about 69 times slower than sarin and 20 times slower than water.
Also unlike sarin, cyclosarin is flammable
Flammability
Flammability is defined as how easily something will burn or ignite, causing fire or combustion. The degree of difficulty required to cause the combustion of a substance is quantified through fire testing. Internationally, a variety of test protocols exist to quantify flammability...
, with a flash point
Flash point
The flash point of a volatile material is the lowest temperature at which it can vaporize to form an ignitable mixture in air. Measuring a flash point requires an ignition source...
of 94 °C (201 °F).
Cyclosarin (GF) also demonstrates greater toxicity than sarin (GB) in humans. Sarin has a median lethal dose (LD50) of 5 mg (for a 70 kg human), while GF has an LD50 of 1.2 mg. The median lethal concentration and time (LCt50) of cyclosarin is 50 mg⋅min/m3, which is half that of GB.
History
First synthesized during World War IIWorld War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
as part of Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
's chemical weapons research on organophosphate compounds after their military potential was discovered, cyclosarin was also studied later in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
and Great Britain
Great Britain
Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...
in the early 1950s
1950s
The 1950s or The Fifties was the decade that began on January 1, 1950 and ended on December 31, 1959. The decade was the sixth decade of the 20th century...
as part of a systematic study of potential nerve agents. It was never selected for mass production, however, due to its precursors being more expensive than those of other G-series nerve agents such as sarin (GB).
To date, Iraq is the only nation known to have manufactured significant quantities of cyclosarin for use as a chemical agent and to actually deploy it in battle. During the Iran-Iraq war
Iran-Iraq War
The Iran–Iraq War was an armed conflict between the armed forces of Iraq and Iran, lasting from September 1980 to August 1988, making it the longest conventional war of the twentieth century...
(1986–1988) the Iraqis used sarin and cyclosarin together as a mixture. This was likely done to obtain a more persistent chemical agent as well as in response to an existing embargo placed on alcohol precursors for sarin.
Binary weapons
Like other nerve agents, cyclosarin can be shipped in binary munitions.A cyclosarin binary weapon would most likely contain methylphosphonyl difluoride
Methylphosphonyl difluoride
Methylphosphonyl difluoride , also called methyl difluorophosphite, methylphosphonic difluoride, and difluoromethylphosphine oxide, is a chemical weapon precursor. It is a Schedule 1 substance in the sense of the Chemical Weapons Convention...
in one capsule, with the other capsule containing either cyclohexanol
Cyclohexanol
Cyclohexanol is the organic compound with the formula 5CHOH. The molecule is related to cyclohexane ring by replacement of one hydrogen atom by a hydroxyl group. This compound exists as a deliquescent colorless solid, which, when very pure, melts near room temperature...
or a mixture of cyclohexylamine
Cyclohexylamine
Cyclohexylamine, also called hexahydroaniline, 1-aminocyclohexane, or aminohexahydrobenzene, is an organic chemical, an amine derived from cyclohexane. It is a clear to yellowish liquid with fishy odor, with melting point of −17.7 °C and boiling point 134.5 °C, miscible with water...
and cyclohexanol.
GB-GF Mixtures
According to CBWInfo.com, IraqIraq
Iraq ; officially the Republic of Iraq is a country in Western Asia spanning most of the northwestern end of the Zagros mountain range, the eastern part of the Syrian Desert and the northern part of the Arabian Desert....
fielded munitions filled with a mixture of GB (sarin) and GF (cyclosarin). Tests on mice indicated that GB-GF mixtures have a relative toxicity between GF and GB.