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Arsenate Of Lead
Lead hydrogen arsenate, also called lead arsenate, acid lead arsenate or LA, chemical formula PbHAsO4, is an inorganic insecticide used primarily against the potato beetle. Lead arsenate was the most extensively used arsenical insecticide.Peryea F.J. 1998. Historical use of lead arsenate insecticides, resulting in soil contamination and implications for soil remediation. Proceedings, 16th World Congress of Soil Science, Montpellier, France. 20-26. Aug. Available online: http://soils.tfrec.wsu.edu/leadhistory.htm Two principal formulations of lead arsenate were marketed: basic lead arsenate (Pb5OH(AsO4)3, CASN: 1327-31-7) and acid lead arsenate (PbHAsO4). Production and structure It is usually produced using the following reaction, which leads to formation of the desired product as a solid precipitate: :Pb(NO3)2 + H3AsO4 → PbHAsO4 +2 HNO3 It has the same structure as the hydrogen phosphate PbHPO4. Like lead sulfate PbSO4, these salts are poorly soluble. Uses As an insecticid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pb2+
Lead is a chemical element with the Symbol (chemistry), symbol Pb (from the Latin ) and atomic number 82. It is a heavy metals, heavy metal that is density, denser than most common materials. Lead is Mohs scale of mineral hardness#Intermediate hardness, soft and malleable, and also has a relatively low melting point. When freshly cut, lead is a shiny gray with a hint of blue. It tarnishes to a dull gray color when exposed to air. Lead has the highest atomic number of any stable nuclide, stable element and three of its isotopes are endpoints of major nuclear decay chains of heavier elements. Lead is toxic, even in small amounts, especially to children. Lead is a relatively unreactive post-transition metal. Its weak metallic character is illustrated by its amphoteric nature; lead and lead oxides react with acids and base (chemistry), bases, and it tends to form covalent bonds. Compounds of lead are usually found in the +2 oxidation state rather than the +4 state common with lighte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crab Grass
''Digitaria'' is a genus of plants in the grass family native to tropical and warm temperate regions but can occur in tropical, subtropical, and cooler temperate regions as well. Common names include crabgrass, finger-grass, and fonio. They are slender monocotyledonous annual and perennial lawn, pasture, and forage plants; some are often considered lawn pests. ''Digitus'' is the Latin word for "finger", and they are distinguished by the long, finger-like inflorescences they produce. Uses The seeds are edible, most notably those of fonio (''Digitaria exilis'' and ''Digitaria iburua''), ''Digitaria sanguinalis'', as well as ''Digitaria compacta''. They can be toasted, ground into a flour, made into porridge or fermented to make beer. Fonio has been widely used as a staple crop in parts of Africa. It also has decent nutrient qualities as a forage for cattle. Lawns The prevalent species of ''Digitaria'' in North America are large crabgrass (''D. sanguinalis''), sometimes known ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Compounds
Hydrogen compounds are compounds containg the element hydrogen. In these compounds, hydrogen can form in the +1 and -1 oxidation states. Hydrogen can form compounds both ionically and in covalent substances. It is a part of many organic compounds such as hydrocarbons as well as water and other organic substances. The ion is often called a proton because it has one proton and no electrons, although the proton does not move freely. Brønsted–Lowry acids are capable of donating ions to bases. Covalent and organic compounds While is not very reactive under standard conditions, it does form compounds with most elements. Hydrogen can form compounds with elements that are more electronegative, such as halogens (F, Cl, Br, I), or oxygen; in these compounds hydrogen takes on a partial positive charge. When bonded to a more electronegative element, particularly fluorine, oxygen, or nitrogen, hydrogen can participate in a form of medium-strength noncovalent bonding with another elect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead(II) Compounds
Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cut, lead is a shiny gray with a hint of blue. It tarnishes to a dull gray color when exposed to air. Lead has the highest atomic number of any stable element and three of its isotopes are endpoints of major nuclear decay chains of heavier elements. Lead is toxic, even in small amounts, especially to children. Lead is a relatively unreactive post-transition metal. Its weak metallic character is illustrated by its amphoteric nature; lead and lead oxides react with acids and bases, and it tends to form covalent bonds. Compounds of lead are usually found in the +2 oxidation state rather than the +4 state common with lighter members of the carbon group. Exceptions are mostly limited to organolead compounds. Like the lighter members of the group, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium Arsenate
Calcium arsenate is the inorganic compound with the formula Ca3(AsO4)2. A colourless salt, it was originally used as a pesticide and as a germicide. It is highly soluble in water, in contrast to lead arsenate, which makes it more toxic. The minerals rauenthalite Ca3(AsO4)2·10H2O and phaunouxite Ca3(AsO4)2·11H2O are hydrates of calcium arsenate. Preparation Calcium arsenate is commonly prepared from disodium hydrogen arsenate and calcium chloride: :2 Na2H sO4 + 3 CaCl2 → 4 NaCl + Ca3 sO4sub>2 + 2 HCl In the 1920s, it was made in large vats by mixing calcium oxide and arsenic oxide. In the United States, 1360 metric tons were produced in 1919, 4540 in 1920, and 7270 in 1922. The composition of commercially available calcium arsenate varies from manufacturer to manufacturer. A typical composition is 80-85% of Ca3(AsO4)2 a basic arsenate probably with a composition of 4CaO.As2O5 together with calcium hydroxide and calcium carbonate. Use as a herbicide It was once a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sherwin-Williams Brand Lime Sulphur And Arsenate Of Lead Advertisement 1911 Door County Democrat
Sherwin-Williams Company is an American Cleveland, Ohio–based company in the paint and coating manufacturing industry. The company primarily engages in the manufacture, distribution, and sale of paints, coatings, floorcoverings, and related products to professional, industrial, commercial, and retail customers primarily in North and South America and Europe. At the end of 2020, Sherwin-Willams had operations in over 120 countries. History Sherwin-Williams dates from 1866, when Cleveland bookkeeper Henry Sherwin invested in Truman Dunham & Co., a paint distributorship. After the partnership dissolved in 1870, he formed Sherwin, Williams, & Co. with Edward Williams and A.T. Osborn. For its first factory, in 1873 the company acquired a cooperage in Cleveland from Standard Oil. Sherwin-Williams was incorporated in Ohio on July 16, 1884, two years after Osborn sold his interest in the company while retaining the retail operations. The company grew through acquisitions and expans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arsenic
Arsenic is a chemical element with the symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, but only the gray form, which has a metallic appearance, is important to industry. The primary use of arsenic is in alloys of lead (for example, in car batteries and ammunition). Arsenic is a common n-type dopant in semiconductor electronic devices. It is also a component of the III-V compound semiconductor gallium arsenide. Arsenic and its compounds, especially the trioxide, are used in the production of pesticides, treated wood products, herbicides, and insecticides. These applications are declining with the increasing recognition of the toxicity of arsenic and its compounds. A few species of bacteria are able to use arsenic compounds as respiratory metabolites. Trace quantities of arsenic are an essential dietary element in r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead
Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cut, lead is a shiny gray with a hint of blue. It tarnishes to a dull gray color when exposed to air. Lead has the highest atomic number of any stable element and three of its isotopes are endpoints of major nuclear decay chains of heavier elements. Lead is toxic, even in small amounts, especially to children. Lead is a relatively unreactive post-transition metal. Its weak metallic character is illustrated by its amphoteric nature; lead and lead oxides react with acids and bases, and it tends to form covalent bonds. Compounds of lead are usually found in the +2 oxidation state rather than the +4 state common with lighter members of the carbon group. Exceptions are mostly limited to organolead compounds. Like the lighter members of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bioaccumulation
Bioaccumulation is the gradual accumulation of substances, such as pesticides or other chemicals, in an organism. Bioaccumulation occurs when an organism absorbs a substance at a rate faster than that at which the substance is lost or eliminated by catabolism and excretion. Thus, the longer the biological half-life of a toxic substance, the greater the risk of chronic poisoning, even if environmental levels of the toxin are not very high. Bioaccumulation, for example in fish, can be predicted by models. Hypothesis for molecular size cutoff criteria for use as bioaccumulation potential indicators are not supported by data. Biotransformation can strongly modify bioaccumulation of chemicals in an organism. Toxicity induced by metals is associated with bioaccumulation and biomagnification. Storage or uptake of metals faster than the rate at which an organism metabolizes and excretes lead to the accumulation of that metal. The presence of various chemicals and harmful substances i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orchard
An orchard is an intentional plantation of trees or shrubs that is maintained for food production. Orchards comprise fruit- or nut-producing trees which are generally grown for commercial production. Orchards are also sometimes a feature of large gardens, where they serve an aesthetic as well as a productive purpose. A fruit garden is generally synonymous with an orchard, although it is set on a smaller non-commercial scale and may emphasize berry shrubs in preference to fruit trees. Most temperate-zone orchards are laid out in a regular grid, with a grazed or mown grass or bare soil base that makes maintenance and fruit gathering easy. Most modern commercial orchards are planted for a single variety of fruit. While the importance of introducing biodiversity is recognized in forest plantations, it would seem to be beneficial to introduce some genetic diversity in orchard plantations as well by interspersing other trees through the orchard. Genetic diversity in an orchard ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morchella
''Morchella'', the true morels, is a genus of edible sac fungi closely related to anatomically simpler cup fungi in the order Pezizales ( division Ascomycota). These distinctive fungi have a honeycomb appearance due to the network of ridges with pits composing their caps. Morels are prized by gourmet cooks, particularly in Catalan and French cuisine. Due to difficulties in cultivation, commercial harvesting of wild morels has become a multimillion-dollar industry in the temperate Northern Hemisphere, in particular North America, Turkey, China, the Himalayas, India, and Pakistan where these highly prized fungi are found in abundance. Typified by '' Morchella esculenta'' in 1794, the genus has been the source of considerable taxonomical controversy throughout the years, mostly with regard to the number of species involved, with some mycologists recognising as few as three species and others over thirty. Current molecular phylogenetics suggest there might be over seventy spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LD50
In toxicology, the median lethal dose, LD50 (abbreviation for "lethal dose, 50%"), LC50 (lethal concentration, 50%) or LCt50 is a toxic unit that measures the lethal dose of a toxin, radiation, or pathogen. The value of LD50 for a substance is the Dose (pharmacology), dose required to kill half the members of a tested population after a specified test duration. LD50 figures are frequently used as a general indicator of a substance's acute toxicity. A lower LD50 is indicative of increased toxicity. The test was created by J.W. Trevan in 1927. The term semilethal dose is occasionally used in the same sense, in particular with translations of foreign language text, but can also refer to a sublethal dose. LD50 is usually determined by tests on animals such as Laboratory mouse, laboratory mice. In 2011, the U.S. Food and Drug Administration approved alternative methods to LD50 for testing the cosmetic drug Botox without animal tests. Conventions The LD50 is usually expressed as the m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
