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Bismuth Subcarbonate
Bismuth subcarbonate (BiO)2CO3, sometimes written Bi2O2(CO3) is a chemical compound of bismuth containing both oxide and carbonate anions. Bismuth is in the +3 oxidation state. Bismuth subcarbonate occurs naturally as the mineral bismutite. Its structure consists of Bi–O layers and CO3 layers and is related to kettnerite, CaBi(CO3)OF. It is light-sensitive. Uses It is highly radiopaque and for example is used as a filler in radiopaque catheters which can be seen by x-ray. In modern medicine, bismuth subcarbonate has been made into nanotube arrays that exhibit antibacterial properties. It is also used in fireworks to make Dragon's eggs. It is a constituent of milk of bismuth which was a popular digestive tract panacea in the 1930s. Safety Bismuth subcarbonate may be harmful if swallowed. It may irritate the respiratory and gastrointestinal tract. Synthesis Bismuth subcarbonate can be attained from the reaction between bismuth nanoparticles and the atmospheric carbon diox ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bismuth
Bismuth is a chemical element with the Symbol (chemistry), symbol Bi and atomic number 83. It is a post-transition metal and one of the pnictogens, with chemical properties resembling its lighter group 15 siblings arsenic and antimony. Elemental bismuth occurs naturally, and its sulfide and oxide forms are important commercial ores. The free element is 86% as dense as lead. It is a brittle metal with a silvery-white color when freshly produced. Passivation (chemistry), Surface oxidation generally gives samples of the metal a somewhat rosy cast. Further oxidation under heat can give bismuth a vividly Iridescence, iridescent appearance due to thin-film interference. Bismuth is both the most Diamagnetism, diamagnetic element and one of the least Thermal conductivity, thermally conductive metals known. Bismuth was long considered the element with the highest atomic mass whose nuclei do not spontaneously decay. However, in 2003 it was discovered to be extremely weakly radioactive. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxide
An oxide () is a chemical compound that contains at least one oxygen atom and one other element in its chemical formula. "Oxide" itself is the dianion of oxygen, an O2– (molecular) ion. with oxygen in the oxidation state of −2. Most of the Earth's crust consists of oxides. Even materials considered pure elements often develop an oxide coating. For example, aluminium foil develops a thin skin of Al2O3 (called a passivation layer) that protects the foil from further corrosion.Greenwood, N. N.; & Earnshaw, A. (1997). Chemistry of the Elements (2nd Edn.), Oxford:Butterworth-Heinemann. . Stoichiometry (the measurable relationship between reactants and chemical equations of a equation or reaction) Oxides are extraordinarily diverse in terms of stoichiometries and in terms of the structures of each stoichiometry. Most elements form oxides of more than one stoichiometry. A well known example is carbon monoxide and carbon dioxide.Greenwood, N. N.; & Earnshaw, A. (1997). Chemistry ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbonate
A carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word ''carbonate'' may also refer to a carbonate ester, an organic compound containing the carbonate group C(=O)(O–)2. The term is also used as a verb, to describe carbonation: the process of raising the concentrations of carbonate and bicarbonate ions in water to produce carbonated water and other carbonated beverageseither by the addition of carbon dioxide gas under pressure or by dissolving carbonate or bicarbonate salts into the water. In geology and mineralogy, the term "carbonate" can refer both to carbonate minerals and carbonate rock (which is made of chiefly carbonate minerals), and both are dominated by the carbonate ion, . Carbonate minerals are extremely varied and ubiquitous in chemically precipitated sedimentary rock. The most common are calcite or calcium carbonate, CaCO3, the chief constituent of limestone (as well a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxidation State
In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. Conceptually, the oxidation state may be positive, negative or zero. While fully ionic bonds are not found in nature, many bonds exhibit strong ionicity, making oxidation state a useful predictor of charge. The oxidation state of an atom does not represent the "real" formal charge on that atom, or any other actual atomic property. This is particularly true of high oxidation states, where the ionization energy required to produce a multiply positive ion is far greater than the energies available in chemical reactions. Additionally, the oxidation states of atoms in a given compound may vary depending on the choice of electronegativity scale used in their calculation. Thus, the oxidation state of an atom in a compound is purely a formalism. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bismutite
Bismutite or bismuthite is a bismuth carbonate mineral with formula Bi2(CO3)O2 (bismuth subcarbonate). Bismutite occurs as an oxidation product of other bismuth minerals such as bismuthinite and native bismuth in hydrothermal veins and pegmatites. It crystallizes in the orthorhombic system and typically occurs as earthy to fibrous masses. It was first described in 1841 for an occurrence in Saxony. The term bismuthite has been used in the past for bismuthinite Bismuthinite is a mineral consisting of bismuth(III) sulfide, bismuth sulfide (bismuth, Bi2sulfur, S3). It is an important ore for bismuth. The crystals are steel-grey to off-white with a metallic luster. It is soft enough to be scratched with .... References Carbonate minerals Bismuth minerals Orthorhombic minerals Minerals in space group 71 {{carbonate-mineral-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiodensity
Radiodensity (or radiopacity) is opacity to the radio wave and X-ray portion of the electromagnetic spectrum: that is, the relative inability of those kinds of electromagnetic radiation to pass through a particular material. Radiolucency or hypodensity indicates greater passage (greater transradiancy) to X-ray photonsNovelline, Robert. ''Squire's Fundamentals of Radiology''. Harvard University Press. 5th edition. 1997. . and is the analogue of transparency and translucency with visible light. Materials that inhibit the passage of electromagnetic radiation are called radiodense or radiopaque, while those that allow radiation to pass more freely are referred to as radiolucent. Radiopaque volumes of material have white appearance on radiographs, compared with the relatively darker appearance of radiolucent volumes. For example, on typical radiographs, bones look white or light gray (radiopaque), whereas muscle and skin look black or dark gray, being mostly invisible (radiolucent). Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filler (materials)
Filler materials are particles added to resin or binders (plastics, composites, concrete) that can improve specific properties, make the product cheaper, or a mixture of both. The two largest segments for filler material use is elastomers and plastics. Worldwide, more than 53 million tons of fillers (with a total sum of approximately US$18 billion) are used every year in application areas such as paper, plastics, rubber, paints, coatings, adhesives, and sealants. As such, fillers, produced by more than 700 companies, rank among the world's major raw materials and are contained in a variety of goods for daily consumer needs. The top filler materials used are ground calcium carbonate (GCC), precipitated calcium carbonate (PCC), kaolin, talc, and carbon black. Filler materials can affect the tensile strength, toughness, heat resistance, color, clarity etc. A good example of this is the addition of talc to polypropylene. Most of the filler materials used in plastics are mineral or glas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catheter
In medicine, a catheter (/ˈkæθətər/) is a thin tube made from medical grade materials serving a broad range of functions. Catheters are medical devices that can be inserted in the body to treat diseases or perform a surgical procedure. Catheters are manufactured for specific applications, such as cardiovascular, urological, gastrointestinal, neurovascular and ophthalmic procedures. The process of inserting a catheter is ''catheterization''. In most uses, a catheter is a thin, flexible tube (''soft'' catheter) though catheters are available in varying levels of stiffness depending on the application. A catheter left inside the body, either temporarily or permanently, may be referred to as an "indwelling catheter" (for example, a peripherally inserted central catheter). A permanently inserted catheter may be referred to as a "permcath" (originally a trademark). Catheters can be inserted into a body cavity, duct, or vessel, brain, skin or adipose tissue. Functionally, they all ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Non-carbon Nanotube
A non-carbon nanotube is a cylindrical molecule often composed of metal oxides, or group III-Nitrides and morphologically similar to a carbon nanotube. Non-carbon nanotubes have been observed to occur naturally in some mineral deposits. A few years after Linus Pauling mentioned the possibility of curved layers in minerals as early as 1930, some minerals such as white asbestos (or chrysotile) and imogolite were actually shown to have a tubular structure. However, the first synthetic non-carbon nanotubes did not appear until Reshef Tenne ''et al.'' reported the synthesis of nanotubes composed of tungsten disulfide (WS2) in 1992. In the intervening years, nanotubes have been synthesised of many non-carbon materials, such as vanadium oxide and manganese oxide, and are being researched for such applications as redox catalysts and cathode materials for batteries. History and occurrence Non-carbon nanotubes are morphologically similar to carbon nanotubes and are observed in some minera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dragon's Egg
''Dragon's Egg'' is a 1980 hard science fiction novel by American writer Robert L. Forward. In the story, Dragon's Egg is a neutron star with a surface gravity 67 billion times that of Earth, and inhabited by cheela, intelligent creatures the size of a sesame seed who live, think and develop a million times faster than humans. Most of the novel, from May to June 2050, chronicles the cheela civilization beginning with its discovery of agriculture to advanced technology and its first face-to-face contact with humans, who are observing the hyper-rapid evolution of the cheela civilization from orbit around Dragon's Egg. As is typical of the genre, ''Dragon's Egg'' attempts to communicate unfamiliar ideas and imaginative scenes while giving adequate attention to the known scientific principles involved. Plot summary The neutron star Half a million years ago and 50 light-years from Earth, a star in the constellation Draco turns supernova, and the star's remnant becomes a neutr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Panacea (medicine)
A panacea , named after the Greek goddess of universal remedy Panacea, is any supposed remedy that is claimed (for example) to cure all diseases and prolong life indefinitely. It was in the past sought by alchemists in connection with the elixir of life and the philosopher's stone, a mythical substance that would enable the transmutation of common metals into gold. Through the 18th and 19th centuries, many "patent medicines" were claimed to be panaceas, and they became very big business. The term "panacea" is used in a negative way to describe the overuse of any one solution to solve many different problems, especially in medicine. The word has acquired connotations of snake oil and quackery. A panacea (or ''panaceum'') is also a literary term to represent any solution to solve all problems related to a particular issue. Mythology In Greek mythology, Panacea was one of the daughters of the Greek god of medicine Asclepius, along with her four sisters, each of whom performed one ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
