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Sodium Hydrosulfide
Sodium hydrosulfide is the chemical compound with the formula NaSH. This compound is the product of the half-neutralization of hydrogen sulfide () with sodium hydroxide (NaOH). NaSH and sodium sulfide are used industrially, often for similar purposes. Solid NaSH is colorless. The solid has an odor of owing to hydrolysis by atmospheric moisture. In contrast with sodium sulfide (), which is insoluble in organic solvents, NaSH, being a 1:1 electrolyte, is more soluble. Structure and properties Crystalline NaSH undergoes two phase transitions. At temperatures above 360 K, NaSH adopts the NaCl structure, which implies that the behaves as a spherical anion owing to its rapid rotation, leading to equal occupancy of eight equivalent positions. Below 360 K, a rhombohedral structure forms, and the sweeps out a discoidal shape. Below 114 K, the structure becomes monoclinic. The analogous rubidium and potassium compounds behave similarly. NaSH has a relatively low melting p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deliquescent
Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption (chemistry), absorption or adsorption from the surrounding Natural environment, environment, which is usually at normal or room temperature. If water molecules become suspended among the substance's molecules, adsorbing substances can become physically changed, e.g. changing in volume, boiling point, viscosity or some other physical characteristic or property of the substance. For example, a finely dispersed hygroscopic powder, such as a salt, may become clumpy over time due to collection of moisture from the surrounding environment. ''Deliquescent'' materials are sufficiently hygroscopic that they dissolve in the water they absorb, forming an aqueous solution. Hygroscopy is essential for many plant and animal species' attainment of hydration, nutrition, reproduction and/or seed dispersal. Biological evolution created hygroscopic solutions for water harvesting, filament tensile strength, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monoclinic
In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three Vector (geometric), vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic system. They form a parallelogram prism (geometry), prism. Hence two pairs of vectors are perpendicular (meet at right angles), while the third pair makes an angle other than 90°. Bravais lattices Two monoclinic Bravais lattices exist: the primitive monoclinic and the base-centered monoclinic. For the base-centered monoclinic lattice, the primitive cell has the shape of an oblique rhombic prism;See , row mC, column Primitive, where the cell parameters are given as a1 = a2, α = β it can be constructed because the two-dimensional centered rectangular base layer can also be described with primitive rhombic axes. The length a of the primitive cell below equals \frac \sqrt of the conventional cell above. Crystal class ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mineral
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): Minerals'; p. 1. In the series ''Geology: Landforms, Minerals, and Rocks''. Rosen Publishing Group. The Geology, geological definition of mineral normally excludes compounds that occur only in living organisms. However, some minerals are often biogenic (such as calcite) or organic compounds in the sense of chemistry (such as mellite). Moreover, living organisms often synthesize inorganic minerals (such as hydroxylapatite) that also occur in rocks. The concept of mineral is distinct from rock (geology), rock, which is any bulk solid geologic material that is relatively homogeneous at a large enough scale. A rock may consist of one type of mineral or may be an aggregate (geology), aggregate of two or more different types of minerals, spaci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copper Extraction
Copper extraction is the multi-stage process of obtaining copper from list of copper ores, its ores. The conversion of copper ores consists of a series of physical, chemical, and electrochemical processes. Methods have evolved and vary with country depending on the ore source, local environmental law, environmental regulations, and other factors. The copper smelters with the highest production capacity (metric tons of copper yearly) lie in China, Chile, India, Germany, Japan, Peru and Russia. China alone has over half of the world's production capacity and is also the world's largest consumer of refined copper. Precious metals and sulfuric acid are often valuable by-products of copper refining. Arsenic is the main type of impurity found in copper concentrates to enter smelting facilities. There has been an increase in arsenic in copper concentrates over the years since shallow, low-arsenic copper deposits have been progressively depleted. History Prehistory The Old Copper Compl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kraft Process
The kraft process (also known as kraft pulping or sulfate process) is a process for conversion of wood into wood pulp, which consists of almost pure cellulose fibres, the main component of paper. The kraft process involves treatment of wood chips with a hot mixture of water, sodium hydroxide (NaOH), and sodium sulfide (Na2S), known as white liquor, that breaks the bonds that link lignin, hemicellulose, and cellulose. The technology entails several steps, both mechanical and chemical. It is the dominant method for producing paper. In some situations, the process has been controversial because kraft plants can release odorous products and in some situations produce substantial liquid wastes. The process name is derived from the German word ''wikt:Kraft#German, Kraft'', meaning "strength" in this context, due to the strength of the kraft paper produced using this process. History A precursor of the kraft process was used during the Napoleonic Wars in England. The kraft process ... [...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] |
Inorganic Syntheses
''Inorganic Syntheses'' is a book series which aims to publish "detailed and foolproof" procedures for the synthesis of inorganic compounds. Although this series of books are edited, they usually are referenced like a journal, without mentioning the names of the checkers (referees) or the editor. A similar format is usually followed for the series '' Organic Syntheses''. Volumes See also * Organic SynthesesReferences {{chem-book-stub Book series introduced in 1939 ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Ethoxide
Sodium ethoxide, also referred to as sodium ethanolate, is the Ionic compound, ionic, organic compound with the formula , , or NaOEt (Et = ethyl group, ethyl). It is a white solid, although impure samples appear yellow or brown. It dissolves in polar solvents such as ethanol. It is commonly used as a strong Base (chemistry), base. Preparation Few procedures have been reported to prepare the anhydrous solid. Instead the material is typically prepared in a solution with ethanol. It is commercially available and as a solution in ethanol. It is easily prepared in the laboratory by treating sodium metal with absolute ethanol: : The reaction of sodium hydroxide with anhydrous ethanol suffers from incomplete conversion to the ethoxide, but can still produce dry NaOEt by precipitation using acetone, or by drying using additional NaOH. Structure The crystal structure of sodium ethoxide has been determined by X-ray crystallography. It consists of layers of alternating and centres with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potassium
Potassium is a chemical element; it has Symbol (chemistry), symbol K (from Neo-Latin ) and atomic number19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to form flaky white potassium peroxide in only seconds of exposure. It was first isolated from potash, the ashes of plants, from which its name derives. In the periodic table, potassium is one of the alkali metals, all of which have a single valence electron in the outer electron shell, which is easily removed to create cation, an ion with a positive charge (which combines with anions to form salts). In nature, potassium occurs only in ionic salts. Elemental potassium reacts vigorously with water, generating sufficient heat to ignite hydrogen emitted in the reaction, and burning with a lilac-flame color, colored flame. It is found dissolved in seawater (which is 0.04% potassium by weight), and occurs in many minerals such as orthoclase, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rubidium
Rubidium is a chemical element; it has Symbol (chemistry), symbol Rb and atomic number 37. It is a very soft, whitish-grey solid in the alkali metal group, similar to potassium and caesium. Rubidium is the first alkali metal in the group to have a density higher than Properties of water, water. On Earth, natural rubidium comprises two isotopes: 72% is a stable isotope Rb, and 28% is slightly radioactive Rb, with a half-life of 48.8 billion years – more than three times as long as the estimated age of the universe. German chemists Robert Bunsen and Gustav Kirchhoff discovered rubidium in 1861 by the newly developed technique, Atomic emission spectroscopy#Flame emission spectroscopy, flame spectroscopy. The name comes from the Latin word , meaning deep red, the color of its emission spectrum. Rubidium's compounds have various chemical and electronic applications. Rubidium metal is easily vaporized and has a convenient spectral absorption range, making it a frequent target for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhombohedral
In geometry, a rhombohedron (also called a rhombic hexahedron or, inaccurately, a rhomboid) is a special case of a parallelepiped in which all six faces are congruent rhombus, rhombi. It can be used to define the rhombohedral lattice system, a Honeycomb (geometry), honeycomb with rhombohedral cells. A rhombohedron has two opposite Apex_(geometry), apices at which all face angles are equal; a prolate rhombohedron has this common angle acute, and an oblate rhombohedron has an obtuse angle at these vertices. A cube is a special case of a rhombohedron with all sides square. Special cases The common angle at the two apices is here given as \theta. There are two general forms of the rhombohedron: oblate (flattened) and prolate (stretched). In the oblate case \theta > 90^\circ and in the prolate case \theta < 90^\circ. For the figure is a cube. Certain proportions of the rhombs give rise to some well-known special cases. These typically occur in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
