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Cacodylic Acid
Cacodylic acid is an organoarsenic compound with the formula (CH3)2 AsO2H. With the formula R2As(O)OH, it is the simplest of the arsinic acids. It is a colorless solid that is soluble in water. Neutralization of cacodylic acid with base gives cacodylate salts, e.g. sodium cacodylate. They are potent herbicides. Cacodylic acid/sodium cacodylate is a buffering agent in the preparation and fixation of biological samples for electron microscopy. History In the 18th century it was found that combining and four equivalents of potassium acetate () gives a product called "Cadet's fuming liquid" which contains cacodyl oxide, and cacodyl, . Early research into "cacodyls" was reported by Robert Bunsen at the University of Marburg. Bunsen said of the compounds, "The smell of this body produces instantaneous tingling of the hands and feet, and even giddiness and insensibility... It is remarkable that when one is exposed to the smell of these compounds the tongue becomes covered wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ball-and-stick Model
In chemistry, the ball-and-stick model is a molecular model of a chemical substance which displays both the three-dimensional position of the atoms and the bonds between them. The atoms are typically represented by spheres, connected by rods which represent the bonds. Double and triple bonds are usually represented by two or three curved rods, respectively, or alternately by correctly positioned sticks for the sigma and pi bonds. In a good model, the angles between the rods should be the same as the angles between the bonds, and the distances between the centers of the spheres should be proportional to the distances between the corresponding atomic nuclei. The chemical element of each atom is often indicated by the sphere's color. In a ball-and-stick model, the radius of the spheres is usually much smaller than the rod lengths, in order to provide a clearer view of the atoms and bonds throughout the model. As a consequence, the model does not provide a clear insight about th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cacodyl Oxide
Cacodyl oxide is a chemical compound of the formula CH3)2Assub>2O. This organoarsenic compound is primarily of historical significance since it is sometimes considered to be the first organometallic compound synthesized in relatively pure form. "Cadet's fuming liquid", which is composed of cacodyl and cacodyl oxide, was originally synthesized by heating potassium acetate with arsenic trioxide. It has a disagreeable odor and is toxic. The molecular structure of h2Assub>2O (Ph = phenyl), the tetraphenyl analogue of cacodyl oxide, has been established by X-ray crystallography. See also * Arsenic * Arsine * Cacodylic acid * Lewisite * Cacodyl cyanide Cacodyl cyanide is a highly poisonous organoarsenic compound discovered by Robert Bunsen in the 1840s. It is very volatile and flammable, as it shares the chemical properties of both arsenic and cyanide. Synthesis Cacodyl cyanide can be prepared ... References Cacodyl compounds Foul-smelling chemicals {{organic-compo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agency For Toxic Substances And Disease Registry
The Agency for Toxic Substances and Disease Registry (ATSDR) is a federal public health agency within the United States Department of Health and Human Services. The agency focuses on minimizing human health risks associated with exposure to hazardous substances. It works closely with other federal, state, and local agencies; tribal governments; local communities; and healthcare providers. Its mission is to "Serve the public through responsive public health actions to promote healthy and safe environments and prevent harmful exposures." ATSDR was created as an advisory, nonregulatory agency by the Superfund legislation and was formally organized in 1985. Although ATSDR is an independent operating agency within the Department of Health and Human Services, the Centers for Disease Control and Prevention (CDC) performs many of its administrative functions. The CDC director also serves as the ATSDR administrator, and ATSDR has a joint Office of the Director with the National Center f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inhalation
Inhalation (or Inspiration) happens when air or other gases enter the lungs. Inhalation of air Inhalation of air, as part of the cycle of breathing, is a vital process for all human life. The process is autonomic (though there are exceptions in some disease states) and does not need conscious control or effort. However, breathing can be consciously controlled or interrupted (within limits). Breathing allows oxygen (which humans and a lot of other species need for survival) to enter the lungs, from where it can be absorbed into the bloodstream. Other substances – accidental Examples of accidental inhalation includes inhalation of water (e.g. in drowning), smoke, food, vomitus and less common foreign substances (e.g. tooth fragments, coins, batteries, small toy parts, needles). Other substances – deliberate Recreational use Legal – helium, nitrous oxide ("laughing gas") Illegal – various gaseous, vaporised or aerosolized recreational drugs Medical use Diag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ingestion
Ingestion is the consumption of a substance by an organism. In animals, it normally is accomplished by taking in a substance through the mouth into the gastrointestinal tract, such as through eating or drinking. In single-celled organisms ingestion takes place by absorbing a substance through the cell membrane. Besides nutritional items, substances that may be ingested include medication (where ingestion is termed oral administration), recreational drugs, and substances considered inedible, such as foreign bodies or excrement. Ingestion is a common route taken by pathogenic organisms and poisons entering the body. Ingestion can also refer to a mechanism picking up something and making it enter an internal hollow of that mechanism, e.g. "''a grille was fitted to prevent the pump from ingesting driftwood''". Pathogens Some pathogens are transmitted via ingestion, including viruses, bacteria, and parasites. Most commonly, this takes place via the faecal-oral route. An intermedia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weak Acid
Acid strength is the tendency of an acid, symbolised by the chemical formula HA, to dissociate into a hydron (chemistry), proton, H+, and an anion, A-. The Dissociation (chemistry), dissociation of a strong acid in solution is effectively complete, except in its most concentrated solutions. :HA -> H+ + A- Examples of strong acids are hydrochloric acid (HCl), perchloric acid (HClO4), nitric acid (HNO3) and sulfuric acid (H2SO4). A weak acid is only partially dissociated, with both the undissociated acid and its dissociation products being present, in solution, in Equilibrium chemistry, equilibrium with each other. :HA H+ + A- Acetic acid (CH3COOH) is an example of a weak acid. The strength of a weak acid is quantified by its acid dissociation constant, K_\ce value. The strength of a weak organic chemistry, organic acid may depend on substituent effects. The strength of an inorganic chemistry, inorganic acid is dependent on the oxidation state for the atom to which the prot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Defoliant
A defoliant is any herbicidal chemical sprayed or dusted on plants to cause their leaves to fall off. Defoliants are widely used for the selective removal of weeds in managing croplands and lawns. Worldwide use of defoliants, along with the development of other herbicides and pesticides, allowed for the Green Revolution, an increase in agricultural production in mid-20th century. Defoliants have also been used in warfare as a means to deprive an enemy of food crops and/or hiding cover, most notably by the United Kingdom during the Malayan Emergency and the United States in the Vietnam War. Defoliants were also used by Indonesian forces in various internal security operations. Use and application A primary application of defoliants is the selective killing of plants. Two of the oldest chemical herbicides used as defoliants are 2,4-Dichlorophenoxyacetic acid (2,4-D) and 2,4,5-Trichlorophenoxyacetic acid (2,4,5-T). 2,4-D and 2,4,5-T are absorbed by broad-leafed plants, killi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vietnam War
The Vietnam War (also known by #Names, other names) was a conflict in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. It was the second of the Indochina Wars and was officially fought between North Vietnam and South Vietnam. The north was supported by the Soviet Union, China, and other communist states, while the south was United States in the Vietnam War, supported by the United States and other anti-communism, anti-communist Free World Military Forces, allies. The war is widely considered to be a Cold War-era proxy war. It lasted almost 20 years, with direct U.S. involvement ending in 1973. The conflict also spilled over into neighboring states, exacerbating the Laotian Civil War and the Cambodian Civil War, which ended with all three countries becoming communist states by 1975. After the French 1954 Geneva Conference, military withdrawal from Indochina in 1954 – following their defeat in the First Indochina War – the Viet Minh to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vietnam
Vietnam or Viet Nam ( vi, Việt Nam, ), officially the Socialist Republic of Vietnam,., group="n" is a country in Southeast Asia, at the eastern edge of mainland Southeast Asia, with an area of and population of 96 million, making it the world's sixteenth-most populous country. Vietnam borders China to the north, and Laos and Cambodia to the west. It shares maritime borders with Thailand through the Gulf of Thailand, and the Philippines, Indonesia, and Malaysia through the South China Sea. Its capital is Hanoi and its largest city is Ho Chi Minh City (commonly known as Saigon). Vietnam was inhabited by the Paleolithic age, with states established in the first millennium BC on the Red River Delta in modern-day northern Vietnam. The Han dynasty annexed Northern and Central Vietnam under Chinese rule from 111 BC, until the first dynasty emerged in 939. Successive monarchical dynasties absorbed Chinese influences through Confucianism and Buddhism, and expanded ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agent Blue
Agent Blue is one of the " rainbow herbicides" that is known for its use by the United States during the Vietnam War. It contained a mixture of dimethylarsinic acid (also known as cacodylic acid) and its related salt, sodium cacodylate, and water. Largely inspired by the British use of herbicides and defoliants during the Malayan Emergency, killing rice was a military strategy from the very start of US military involvement in Vietnam. At first, US soldiers attempted to blow up rice paddies and rice stocks, using mortars and hand grenades. But grains of rice were far more durable than they understood, and were not easily destroyed. Every grain that survived was a seed to be collected and planted again. A 1967 report to the International War Crimes Tribunal (founded by Bertrand Russell) stated that "The soldiers discovered that rice is one of the most maddeningly difficult substances to destroy; using thermite metal grenades it is almost impossible to make it burn and, even if on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organometallic Compound
Organometallic chemistry is the study of organometallic compounds, chemical compounds containing at least one chemical bond between a carbon atom of an organic molecule and a metal, including alkali, alkaline earth, and transition metals, and sometimes broadened to include metalloids like boron, silicon, and selenium, as well. Aside from bonds to organyl fragments or molecules, bonds to 'inorganic' carbon, like carbon monoxide (metal carbonyls), cyanide, or carbide, are generally considered to be organometallic as well. Some related compounds such as transition metal hydrides and metal phosphine complexes are often included in discussions of organometallic compounds, though strictly speaking, they are not necessarily organometallic. The related but distinct term "metalorganics, metalorganic compound" refers to metal-containing compounds lacking direct metal-carbon bonds but which contain organic ligands. Metal β-diketonates, alkoxides, dialkylamides, and metal phosphine complex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methyl Group
In organic chemistry, a methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms, having chemical formula . In formulas, the group is often abbreviated as Me. This hydrocarbon group occurs in many organic compounds. It is a very stable group in most molecules. While the methyl group is usually part of a larger molecule, bounded to the rest of the molecule by a single covalent bond (), it can be found on its own in any of three forms: methanide anion (), methylium cation () or methyl radical (). The anion has eight valence electrons, the radical seven and the cation six. All three forms are highly reactive and rarely observed. Methyl cation, anion, and radical Methyl cation The methylium cation () exists in the gas phase, but is otherwise not encountered. Some compounds are considered to be sources of the cation, and this simplification is used pervasively in organic chemistry. For example, protonation of methanol gives an elect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
