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Nitride Bromide
In chemistry, a nitride is an inorganic compound of nitrogen. The "nitride" anion, N3- ion, is very elusive but compounds of nitride are numerous, although rarely naturally occuring. Some nitrides have a find applications, such as wear-resistant coatings (e.g., titanium nitride, TiN), hard ceramic materials (e.g., silicon nitride, Si3N4), and semiconductors (e.g., gallium nitride, GaN). The development of GaN-based light emitting diodes was recognized by the 2014 Nobel Prize in Physics. Metal nitrido complexes are also common. Synthesis of inorganic metal nitrides is challenging because nitrogen gas (N2) is not very reactive at low temperatures, but it becomes more reactive at higher temperatures. Therefore, a balance must be achieved between the low reactivity of nitrogen gas at low temperatures and the entropy driven formation of N2 at high temperatures. However, synthetic methods for nitrides are growing more sophisticated and the materials are of increasing technological rel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemistry
Chemistry is the scientific study of the properties and behavior of matter. It is a natural science that covers the elements that make up matter to the compounds made of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during a reaction with other substances. Chemistry also addresses the nature of chemical bonds in chemical compounds. In the scope of its subject, chemistry occupies an intermediate position between physics and biology. It is sometimes called the central science because it provides a foundation for understanding both basic and applied scientific disciplines at a fundamental level. For example, chemistry explains aspects of plant growth ( botany), the formation of igneous rocks ( geology), how atmospheric ozone is formed and how environmental pollutants are degraded ( ecology), the properties of the soil on the moon ( cosmochemistry), how medications work (pharmacology), and how to collect DNA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Band Gap
In solid-state physics, a band gap, also called an energy gap, is an energy range in a solid where no electronic states can exist. In graphs of the electronic band structure of solids, the band gap generally refers to the energy difference (in electron volts) between the top of the valence band and the bottom of the conduction band in insulators and semiconductors. It is the energy required to promote a valence electron bound to an atom to become a conduction electron, which is free to move within the crystal lattice and serve as a charge carrier to conduct electric current. It is closely related to the HOMO/LUMO gap in chemistry. If the valence band is completely full and the conduction band is completely empty, then electrons cannot move within the solid because there are no available states. If the electrons are not free to move within the crystal lattice, then there is no generated current due to no net charge carrier mobility. However, if some electrons transfer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium Nitride
Calcium nitride is the inorganic compound with the chemical formula Ca3 N2. It exists in various forms ( isomorphs), α-calcium nitride being more commonly encountered. Structure α-Calcium nitride adopts an anti- bixbyite structure, similar to Mn2O3, except that the positions of the ions are reversed: calcium (Ca2+) take the oxide (O2−) positions and nitride ions (N3−) the manganese (Mn3+). In this structure, Ca2+ occupies tetrahedral sites, and the nitride centres occupy two different types of octahedral sites. Synthesis and reactions Calcium nitride is formed along with the oxide, CaO, when calcium burns in air. It can be produced by direct reaction of the elements: :3 Ca + N2 → Ca3N2 It reacts with water or even the moisture in air to give ammonia and calcium hydroxide Calcium hydroxide (traditionally called slaked lime) is an inorganic compound with the chemical formula Ca( OH)2. It is a colorless crystal or white powder and is produced when quickli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnesium Nitride
Magnesium nitride, which possesses the chemical formula Mg3N2, is an inorganic compound of magnesium and nitrogen. At room temperature and pressure it is a greenish yellow powder. Preparation * By passing dry nitrogen over heated magnesium: ::\begin\\ \ce\\ \end * or ammonia: ::\begin\\ \ce\\ \end History When isolating argon, William Ramsay passed dry air over copper to remove oxygen and over magnesium to remove the nitrogen, forming magnesium nitride. Chemistry Magnesium nitride reacts with water to produce magnesium hydroxide and ammonia gas, as do many metal nitrides. :Mg3N2(s) + 6 H2O(l) → 3 Mg(OH)2(aq) + 2 NH3(g) In fact, when magnesium is burned in air, some magnesium nitride is formed in addition to the principal product, magnesium oxide. Thermal decomposition of magnesium nitride gives magnesium and nitrogen gas (at 700-1500 °C). At high pressures, the stability and formation of new nitrogen-rich nitrides (N/Mg ratio equal or greater to one ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beryllium Nitride
Beryllium nitride, Be3N2, is a nitride of beryllium. It can be prepared from the elements at high temperature (1100–1500 °C);Egon Wiberg, Arnold Frederick Holleman (2001) ''Inorganic Chemistry'', Elsevier unlike beryllium azide or BeN6, it decomposes in vacuum into beryllium and nitrogen. It is readily hydrolysed forming beryllium hydroxide and ammonia. It has two polymorphic forms cubic α-Be3N2 with a defect anti-fluorite structure, and hexagonal β-Be3N2. It reacts with silicon nitride, Si3N4 in a stream of ammonia at 1800–1900 °C to form BeSiN2. Preparation Beryllium nitride is prepared by heating beryllium metal powder with dry nitrogen in an oxygen-free atmosphere in temperatures between 700 and 1400 °C. : 3Be + N2 → Be3N2 Uses It is used in refractory ceramicsHugh O. Pierson, 1996, Handbook of Refractory Carbides and Nitrides: Properties, Characteristics, Processing, and Applications, William Andrew Inc., as well as in nuclear reactors and to prod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkaline Earth Metal
The alkaline earth metals are six chemical elements in group 2 of the periodic table. They are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).. The elements have very similar properties: they are all shiny, silvery-white, somewhat reactive metals at standard temperature and pressure. Structurally, they (together with helium) have in common an outer s-orbital which is full; that is, this orbital contains its full complement of two electrons, which the alkaline earth metals readily lose to form cations with charge +2, and an oxidation state of +2. All the discovered alkaline earth metals occur in nature, although radium occurs only through the decay chain of uranium and thorium and not as a primordial element. There have been experiments, all unsuccessful, to try to synthesize element 120, the next potential member of the group. Characteristics Chemical As with other groups, the members of this family show patterns i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potassium Nitride
Potassium nitride is an unstable chemical compound. Several syntheses were erroneously claimed in the 19th century, and by 1894 it was assumed that it did not exist. However, a synthesis of this compound was claimed in 2004. It is observed to have the anti- structure below , although a -type structure should be more stable. Above this temperature, it converts to an orthorhombic phase. This compound was produced by the reaction of potassium metal and liquid nitrogen at under vacuum: :6K + N2 → 2K3N This compound decomposes back into potassium and nitrogen at room temperature. This compound is unstable due to steric hindrance Steric effects arise from the spatial arrangement of atoms. When atoms come close together there is a rise in the energy of the molecule. Steric effects are nonbonding interactions that influence the shape ( conformation) and reactivity of ions .... References Potassium compounds Nitrides {{Chem-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Nitride
Sodium nitride is the inorganic compound with the chemical formula Na3N. In contrast to lithium nitride and some other nitrides, sodium nitride is an extremely unstable alkali metal nitride. It can be generated by combining atomic beams of sodium and nitrogen deposited onto a low-temperature sapphire substrate. 'Elusive Binary Compound Prepared'''Chemical & Engineering News'' 80 No. 20 (20 May 2002) It readily decomposes into its elements: :2 Na3N -> 6 Na + N2 Synthesis Sodium nitride can be synthesized in two different ways: by the thermal decomposition Thermal decomposition, or thermolysis, is a chemical decomposition caused by heat. The decomposition temperature of a substance is the temperature at which the substance chemically decomposes. The reaction is usually endothermic as heat is req ... of NaNH2 or by the direct reaction of the elements. The most common way to successfully synthesize sodium nitride has been done by Dieter Fischer & Martin Jansen and Grigori V ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkali Metal
The alkali metals consist of the chemical elements lithium (Li), sodium (Na), potassium (K),The symbols Na and K for sodium and potassium are derived from their Latin names, ''natrium'' and ''kalium''; these are still the origins of the names for the elements in some languages, such as German and Russian. rubidium (Rb), caesium (Cs), and francium (Fr). Together with hydrogen they constitute group 1, which lies in the s-block of the periodic table. All alkali metals have their outermost electron in an s-orbital: this shared electron configuration results in their having very similar characteristic properties. Indeed, the alkali metals provide the best example of group trends in properties in the periodic table, with elements exhibiting well-characterised homologous behaviour. This family of elements is also known as the lithium family after its leading element. The alkali metals are all shiny, soft, highly reactive metals at standard temperature and pressure and readil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonia
Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous waste, particularly among aquatic organisms, and it contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to 45% of the world's food and fertilizers. Around 70% of ammonia is used to make fertilisers in various forms and composition, such as urea and Diammonium phosphate. Ammonia in pure form is also applied directly into the soil. Ammonia, either directly or indirectly, is also a building block for the synthesis of many pharmaceutical products and is used in many commercial cleaning products. It is mainly collected by downward displacement of both air and water. Although common in nature—both terrestrially and in the outer planets of the Solar System—and in wide use, ammonia i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrogen Trichloride
Nitrogen trichloride, also known as trichloramine, is the chemical compound with the formula NCl3. This yellow, oily, pungent-smelling and explosive liquid is most commonly encountered as a byproduct of chemical reactions between ammonia-derivatives and chlorine (for example, in swimming pools). Alongside monochloramine and dichloramine, trichloramine is responsible for the distinctive 'chlorine smell' associated with swimming pools, where the compound is readily formed as a product from hypochlorous acid reacting with ammonia and other nitrogenous substances in the water, such as urea from urine. Preparation and structure The compound is prepared by treatment of ammonium salts, such as ammonium nitrate with chlorine. Intermediates in this conversion include monochloramine and dichloramine, NH2Cl and NHCl2, respectively. Like ammonia, NCl3 is a pyramidal molecule. The N-Cl distances are 1.76 Å, and the Cl-N-Cl angles are 107°. Reactions and uses The chemistry of NC ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lithium Nitride
Lithium nitride is a compound with the formula Li3N. It is the only stable alkali metal nitride. The solid has a reddish-pink color and high melting point. Preparation and handling Lithium nitride is prepared by direct combination of elemental lithium with nitrogen gas: :6 Li + N2 → 2 Li3N Instead of burning lithium metal in an atmosphere of nitrogen, a solution of lithium in liquid sodium metal can be treated with N2. Lithium nitride reacts violently with water to produce ammonia: :Li3N + 3 H2O → 3 LiOH + NH3 Structure and properties ''alpha''-Li3N (stable at room temperature and pressure) has an unusual crystal structure that consists of two types of layers, one sheet has the composition Li2N− contains 6-coordinate N centers and the other sheet consists only of lithium cations. Two other forms are known: ''beta''-Lithium nitride, formed from the alpha phase at has the sodium arsenide (Na3As) structure; ''gamma''-Lithium nitride (same structure as Li3Bi) forms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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