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Gallium(III) Sulfide
Gallium(III) sulfide, Ga2S3, is a compound of sulfur and gallium, that is a semiconductor that has applications in electronics and photonics. Structure There are four polymorphs, α (hexagonal), α' (monoclinic), β(hexagonal) and γ(cubic). The alpha form is yellow. The crystal structures are related to those of ZnS with gallium in tetrahedral positions.The Chemistry of Aluminium, Gallium, Indium and Thallium, Anthony John Downs, 1993, , The alpha and beta forms are isostructural with their aluminium analogues. The similarity in crystal form of gamma- with sphalerite (zinc blende), ZnS is believed to explain the enrichment of gallium in sphalerite ores. Preparation and chemical properties Ga2S3 can prepared by reacting the elements at high temperature or as a white solid by heating Ga in a stream of H2S at high temperature (950 °C). It may also prepared by a solid state reaction of GaCl3 and Na2S. The method of production can determine the polymorphic form pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gallium(II) Sulfide
Gallium(II) sulfide, GaS, is a chemical compound of gallium and sulfur. The normal form of gallium(II) sulfide as made from the elements has a hexagonal layer structure containing Ga24+ units which have a Ga-Ga distance of 248pm. This layer structure is similar to GaTe A gate or gateway is a point of entry to or from a space enclosed by walls. The word is derived from Proto-Germanic language, Proto-Germanic ''*gatan'', meaning an opening or passageway. Synonyms include yett (which comes from the same root w ..., GaSe and InSe. An unusual metastable form, with a distorted wurtzite structure has been reported as being produced using MOCVD. The metal organic precursors were di-tert-butyl gallium dithiocarbamates, for example GatBu2(S2CNMe2) and this was deposited onto GaAs. The structure of the GaS produced in this way is presumably Ga2+ S2−. Single layers of gallium sulfide are dynamically stable two-dimensional semiconductors, in which the valence band has an inverte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Sulfide
Sodium sulfide is a chemical compound with the formula Na2 S, or more commonly its hydrate Na2S·9 H2O. Both the anhydrous and the hydrated salts are colorless solids, although technical grades of sodium sulfide are generally yellow to brick red owing to the presence of polysulfides. It is commonly supplied as a crystalline mass, in flake form, or as a fused solid. They are water-soluble, giving strongly alkaline solutions. When exposed to moisture, Na2S immediately hydrates to give sodium hydrosulfide. Sodium sulfide has an unpleasant rotten egg smell due to the hydrolysis to hydrogen sulfide in moist air. Some commercial samples are described as Na2S·''x''H2O, where a weight percentage of Na2S is specified. Commonly available grades have around 60% Na2S by weight, which means that ''x'' is around 3. These grades of sodium sulfide are often marketed as 'sodium sulfide flakes'. These samples consist of NaSH, NaOH, and water. Structure The structures of sodium sulfides have bee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gallium Lanthanum Sulfide Glass
Gallium lanthanum sulfide glass is the name of a family of chalcogenide glasses, referred to as gallium lanthanum sulfide (Ga-La-S) glasses. They are mixtures of LaS, LaO, and GaS, which form the basic glass with other glass modifiers added as needed. Gallium-lanthanum-sulfide glasses have a wide range of vitreous formation centered around a mixture, and readily accept other modifier materials into their structure. This means that Ga-La-S composition can be adjusted to give a wide variety of optical and physical properties. History and physical properties The glass forming ability of gallium(III) sulfide and lanthanum sulfide was discovered in 1976 by Loireau-Lozac’h, Guittard, and Flahut. Optically, Ga-La-S has a high refractive index, a transmission window covering most of the visible wavelengths and extending to about 10 μm and a low maximum phonon energy, approx. 450 cm−1. Thermally, the refractive index of Ga-La-S glasses has a strong temperature dependenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cadmium Sulfide
Cadmium sulfide is the inorganic compound with the formula CdS. Cadmium sulfide is a yellow salt.Egon Wiberg, Arnold Frederick Holleman (2001''Inorganic Chemistry'' Elsevier It occurs in nature with two different crystal structures as the rare minerals greenockite and hawleyite, but is more prevalent as an impurity substituent in the similarly structured zinc ores sphalerite and wurtzite, which are the major economic sources of cadmium. As a compound that is easy to isolate and purify, it is the principal source of cadmium for all commercial applications. Its vivid yellow color led to its adoption as a pigment for the yellow paint "cadmium yellow" in the 1800s. Production Cadmium sulfide can be prepared by the precipitation from soluble cadmium(II) salts with sulfide ion. This reaction has been used for gravimetric analysis and qualitative inorganic analysis.The preparative route and the subsequent treatment of the product, affects the polymorphic form that is produced (i.e., c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphorus Pentoxide
Phosphorus pentoxide is a chemical compound with molecular formula Phosphorus, P4Oxygen, O10 (with its common name derived from its empirical formula, P2O5). This white crystalline solid is the anhydride of phosphoric acid. It is a powerful desiccant and dehydration reaction, dehydrating agent. Structure Phosphorus pentoxide crystallizes in at least four forms or polymorphism (materials science), polymorphs. The most familiar one, a metastable form (shown in the figure), comprises molecules of P4O10. Weak van der Waals forces hold these molecules together in a hexagonal lattice (However, in spite of the high symmetry of the molecules, the crystal packing is not a close packing). The structure of the P4O10 cage is reminiscent of adamantane with ''T''d symmetry point group. It is closely related to the corresponding anhydride of phosphorous acid, phosphorus trioxide, P4O6. The latter lacks terminal oxo groups. Its density is 2.30 g/cm3. It boils at 423 °C under atmospheric pre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adamantane
Adamantane is an organic compound with formula C10H16 or, more descriptively, (CH)4(CH2)6. Adamantane molecules can be described as the fusion of three cyclohexane rings. The molecule is both rigid and virtually stress-free. Adamantane is the most stable isomer of C10H16. The spatial arrangement of carbon atoms in the adamantane molecule is the same as in the diamond crystal. This similarity led to the name ''adamantane'', which is derived from the Greek ''adamantinos'' (relating to steel or diamond). It is a white solid with a camphor-like odor. It is the simplest diamondoid. The discovery of adamantane in petroleum in 1933 launched a new field of chemistry dedicated to the synthesis and properties of polyhedral organic compounds. Adamantane derivatives have found practical application as drugs, polymeric materials, and thermally stable lubricants. History and synthesis In 1924, H. Decker suggested the existence of adamantane, which he called decaterpene. The first attempted l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potassium Sulfide
Potassium sulfide is an inorganic compound with the formula K2 S. The colourless solid is rarely encountered, because it reacts readily with water, a reaction that affords potassium hydrosulfide (KSH) and potassium hydroxide (KOH). Most commonly, the term potassium sulfide refers loosely to this mixture, not the anhydrous solid. Structure It adopts an antifluorite structure, which means that the small K+ ions occupy the tetrahedral (F−) sites in fluorite, and the larger S2− centers occupy the eight-coordinate sites. Li2S, Na2S, and Rb2S crystallize similarly.Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. . Synthesis and reactions It can be produced by heating K2SO4 with carbon ( coke): :K2SO4 + 4 C → K2S + 4 CO In the laboratory, pure K2S may be prepared by the reaction of potassium and sulfur in anhydrous ammonia. Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Non-stoichiometric Compound
Non-stoichiometric compounds are chemical compounds, almost always solid inorganic compounds, having elemental composition whose proportions cannot be represented by a ratio of small natural numbers (i.e. an empirical formula); most often, in such materials, some small percentage of atoms are missing or too many atoms are packed into an otherwise perfect lattice work. Contrary to earlier definitions, modern understanding of non-stoichiometric compounds view them as homogeneous, and not mixtures of stoichiometric chemical compounds. Since the solids are overall electrically neutral, the defect is compensated by a change in the charge of other atoms in the solid, either by changing their oxidation state, or by replacing them with atoms of different elements with a different charge. Many metal oxides and sulfides have non-stoichiometric examples; for example, stoichiometric iron(II) oxide, which is rare, has the formula , whereas the more common material is nonstoichiometric, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gallium Hydroxide
Gallium hydroxide is an inorganic compound with the chemical formula . It is formed as a gel following the addition of ammonia to salts.Anthony John Downs, (1993), ''Chemistry of Aluminium, Gallium, Indium, and Thallium'', Springer, It is also found in nature as the rare mineral söhngeite which is reported to contain octahedrally coordinated gallium atoms. Crystal Structure of a new mineral söhngeite, J.D. Scott, The American Mineralogist, (1971), 56, 355 Gallium hydroxide is amphoteric. In strongly acidic conditions, the gallium ion, is formed. In strongly basic conditions, (tetrahydroxogallate(III)) is formed. Salts of are sometimes called gallate Gallate may refer to: * gallic acid salt, a salt or ester of gallic acid * gallium salt Gallium is a chemical element; it has symbol Ga and atomic number 31. Discovered by the French chemist Paul-Émile Lecoq de Boisbaudran in 1875, elementa ...s. References Hydroxides Gallium compounds {{inorganic-compoun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gallium Trichloride
Gallium(III) chloride is an inorganic chemical compound with the formula which forms a monohydrate, . Solid gallium(III) chloride is a deliquescent colorless crystals and exists as a dimer with the formula . It is colourless and soluble in virtually all solvents, even alkanes, which is unusual for a metal halide. It is the main precursor to most derivatives of gallium and a reagent in organic synthesis. As a Lewis acid, is milder than aluminium chloride. It is also easier to reduce than aluminium chloride. The coordination chemistry of Ga(III) and Fe(III) are similar, so gallium(III) chloride has been used as a diamagnetic analogue of ferric chloride. Preparation Gallium(III) chloride can be prepared from the elements by heating gallium metal in a stream of chlorine at 200 °C and purifying the product by sublimation under vacuum. : It can also be prepared from by heating gallium oxide with thionyl chloride: : Gallium metal reacts slowly with hydrochloric acid, produci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfur
Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with the chemical formula S8. Elemental sulfur is a bright yellow, crystalline solid at room temperature. Sulfur is the tenth most abundant element by mass in the universe and the fifth most common on Earth. Though sometimes found in pure, native form, sulfur on Earth usually occurs as sulfide and sulfate minerals. Being abundant in native form, sulfur was known in ancient times, being mentioned for its uses in ancient India, ancient Greece, China, and ancient Egypt. Historically and in literature sulfur is also called brimstone, which means "burning stone". Almost all elemental sulfur is produced as a byproduct of removing sulfur-containing contaminants from natural gas and petroleum.. Downloahere Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Sulfide
Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is toxic, corrosive, and flammable. Trace amounts in ambient atmosphere have a characteristic foul odor of rotten eggs. Swedish chemist Carl Wilhelm Scheele is credited with having discovered the chemical composition of purified hydrogen sulfide in 1777. Hydrogen sulfide is toxic to humans and most other animals by inhibiting cellular respiration in a manner similar to hydrogen cyanide. When it is inhaled or its salts are ingested in high amounts, damage to organs occurs rapidly with symptoms ranging from breathing difficulties to convulsions and death. Despite this, the human body produces small amounts of this sulfide and its mineral salts, and uses it as a signalling molecule. Hydrogen sulfide is often produced from the microbial breakdown of organic matter in the absence of oxygen, such as in swamps and sewers; this process is commonly known as anaerobic digestio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
