Ammonia is a compound of nitrogen and hydrogen with the formula NH3. At standard temperature and pressure ammonia is a gas. It is toxic and corrosive to some materials, and has a characteristic pungent odor. An ammonia molecule is not flat, but has the shape of a compressed tetrahedron known as a trigonal pyramid, as would be expected from VSEPR theory. This shape gives the molecule an overall dipole moment and makes it polar so that ammonia very readily dissolves in water. The nitrogen atom in the molecule has a lon ...

Including:

• Ammonia - History
• Ammonia - Production
• Ammonia - Properties
• Ammonia - Acidity
• Ammonia - Formation of other compounds
• Ammonia - Ammonia as a ligand
• Ammonia - Uses
• Ammonia - Liquid ammonia as a solvent
• Ammonia - Solubility of salts
• Ammonia - Solutions of metals
• Ammonia - Redox properties of liquid ammonia
• Ammonia - Detection and determination
• Ammonia - Safety precautions
• Ammonia - Toxicity
• Ammonia - Household use
• Ammonia - Laboratory use of ammonia solutions
• Ammonia - Laboratory use of anhydrous ammonia gas or liquid
• Ammonia - Reference
• Ammonia - Bibliography

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The word ceramic is derived from the Greek word κεραμικος (keramikos, "having to do with pottery"). The term covers inorganic non-metallic materials whose formation is due to the action of heat. Up until the 1950s or so, the most important of these were the traditional clays, made into pottery, bricks, tiles and the like, along with cements and glass. The traditional crafts are described in the article on pottery. A composite ma ...

Including:

• Ceramics - Classifications of technical ceramics
• Ceramics - Examples of ceramic materials
• Ceramics - Properties of ceramics
• Ceramics - Mechanical properties
• Ceramics - Electrical properties
• Ceramics - Processing of ceramic materials
• Ceramics - In situ manufacturing
• Ceramics - Sintering-based methods
• Ceramics - Other applications of ceramics

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Cadmium is a chemical element in the periodic table that has the symbol Cd and atomic number 48. A relatively rare, soft, bluish-white, toxic transition metal, cadmium occurs with zinc ores and is used largely in batteries. Cadmium - Notable characteristics. Cadmium is a soft, malleable, ductile, bluish-white bivalent metal which can be easily cut with a knife. It is similar in many respects to zinc but lends itself to more complex compounds. The most common oxidation state of cadmium is +2, t ...

Including:

• Cadmium - Notable characteristics
• Cadmium - Applications
• Cadmium - History
• Cadmium - Occurrence
• Cadmium - Isotopes
• Cadmium - Precautions

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Zirconium is a chemical element in the periodic table that has the symbol Zr and atomic number 40. A lustrous gray-white, strong transition metal that resembles titanium, zirconium is obtained chiefly from zircon and is very corrosion resistant. Zirconium is primarily used in nuclear reactors for a neutron absorber and to make corrosion-resistant alloys. Zirconium - Notable characteristics. It is a grayish-white metal, lustrous and exceptionally corrosion resistant. Zirconium is lighter than steel an ...

Including:

• Zirconium - Notable characteristics
• Zirconium - Applications
• Zirconium - History
• Zirconium - Occurrence
• Zirconium - Isotopes
• Zirconium - Precautions

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A chromophore is the part (or moiety) of a molecule responsible for its color. This is a region in a molecule where the energy difference between two different molecular orbitals falls within the range of the visible spectrum. Light that hits the chromophore can be absorbed by exciting an electron from its ground state into an excited state. When a molecule absorbs certain visible wavelengths in this way, but transmits or reflects others, the molecule has a color. In biological molecules that serve to capture or detect light energy, the chromophore is the moiety that causes a confor ...

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Yttrium is a chemical element in the periodic table that has the symbol Y and atomic number 39. A silvery metallic transition metal, yttrium is common in rare-earth minerals and two of its compounds are used to make the red color in color televisions. Yttrium - Notable Characteristics. Yttrium is a silver-metallic, lustrous rare earth metal that is relatively stable in air and chemically resembles the lanthanides. Shavings or turnings of the metal can ignite in air when they exceed 400 °C. When yttr ...

Including:

• Yttrium - Notable Characteristics
• Yttrium - Applications
• Yttrium - History
• Yttrium - Occurrence
• Yttrium - Isotopes
• Yttrium - Precautions

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A coordinate covalent bond (also known as dative covalent bond) is a special type of covalent bond in which the shared electrons come from one of the atoms only. Once the bond has been formed, its strength is no different from that of a covalent bond. Coordinate covalent bonds are formed when a Lewis base (an electron donor or giver) donates a pair of electrons to a Lewis acid (an electron accepter) and the resultant compound is then called an adduct (a compound formed by the addition reaction between two molecules). The ...

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Alfred Werner (December 12, 1866 - November 15, 1919) was a German Nobel prize-winning chemist. He won the Nobel Prize in Chemistry in 1913 for proposing the octahedral configuration of transition metal complexes. Werner developed the basis for modern coordination chemistry. He also discovered hexol. Alfred Werner - External link. Biography at Nobelprize.org his work on the linkage of atoms in molecules by which he has thrown new light on earlier investigations and opened up new field ...

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• Alfred Werner - External link

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Gold is a chemical element in the periodic table that has the symbol Au (L. aurum) and atomic number 79. A soft, shiny, yellow, dense, malleable, ductile (trivalent and univalent) transition metal, gold does not react with most chemicals but is attacked by chlorine, fluorine and aqua regia. The metal occurs as nuggets or grains in rocks and in alluvial deposits and is one of the coinage metals. For millennia, gold has served as money and is also used in jewellery, dentistry, and in electronics. Gold forms t ...

Including:

• Gold - Notable characteristics
• Gold - Applications
• Gold - History
• Gold - Value
• Gold - Gold and the money supply
• Gold - Restrictions on gold ownership
• Gold - Return of a gold standard?
• Gold - Gold in investment portfolios
• Gold - Occurrence
• Gold - Production
• Gold - Compounds/isotopes
• Gold - Precautions
• Gold - Symbolism

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Silver is a chemical element with the symbol Ag (from the traditional abbreviation for the Latin argentum). A soft white lustrous transition metal, it has the highest electrical and thermal conductivity of any metal and occurs in minerals and in free form. This metal is used in coins, jewelry, tableware, and photography. Silver - Notable characteristics. Silver is a very ductile and malleable (slightly harder than gold) univalent coinage metal with a brilliant white metallic luster that can ta ...

Including:

• Silver - Notable characteristics
• Silver - Applications
• Silver - History
• Silver - Occurrence
• Silver - Isotopes
• Silver - Precautions and health effects

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Niobium has a number of uses: it is a component of some stainless steels and an alloy of other nonferrous metals. These alloys are strong and are often used in pipeline construction. Other uses; The metal has a low capture cross-section for thermal neutrons and so finds use in the nuclear industries. It is also the metal used in arc welding rods for some stabilized grades of stainless steel. Because of its bluish color, niobium is also used in body piercing jewelry (usually as an alloy). Appreciable am ...

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Niobium, Niobium - Notable characteristics, Niobium - Applications, Niobium - History, Niobium - Occurrence, Niobium - Isotopes, Niobium - Precautions

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Molybdenum has been found to have a role in the biology of all classes of organisms. It is found in two groups of enzymes, the nitrogenases and the molybdopterins. The nitrogenases are found in bacteria, and are involved in the pathways of nitrogen fixation. The bacteria may be found inside plants. The molybdenum atom is present in a cluster(see cluster chemistry), which includes iron and sulfur atoms. The name molybdopterin is misleading as the group of enzymes includes tungsten-containing enzymes, and the word "molybdopterin" does n ...

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Molybdenum, Molybdenum - Notable characteristics, Molybdenum - Applications, Molybdenum - History, Molybdenum - Occurrence, Molybdenum - Biological role, Molybdenum - Isotopes, Molybdenum - Precautions, Molybdenum - Toxicity in animals

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Osmium in a metallic form is extremely dense, blue white, brittle and lustrous even at high temperatures, but proves to be extremely difficult to make. Powdered osmium is easier to make, but powdered osmium exposed to air leads to the formation of osmium tetroxide (OsO4), which is toxic. The oxide is also a powerful oxidizing agent, emits a strong smell and boils at 130°C. Due to its very high density osmium is generally considered to be the heaviest known element, narrowly defeating iridium. However, calculations of densi ...

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Osmium, Osmium - Notable characteristics, Osmium - Applications, Osmium - History, Osmium - Occurrence, Osmium - Compounds, Osmium - Isotopes, Osmium - Precautions

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Zirconium (Arabic zarkûn from Persian zargûn meaning "gold like") was discovered in 1789 by Martin Heinrich Klaproth and isolated in 1824 by Jöns Jakob Berzelius. The zirconium containing mineral zircon, or its variations (jargon, hyacinth, jacinth, or ligure), were mentioned in biblical writings. The mineral was not known to contain a new element until Klaproth analyzed a jargon from Ceylon in the Indian Ocean. He named the new element Zirkonertz (zirconia). The impure metal was isolated first by Berzelius by heating ...

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Zirconium, Zirconium - Notable characteristics, Zirconium - Applications, Zirconium - History, Zirconium - Occurrence, Zirconium - Isotopes, Zirconium - Precautions

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The metal appears silvery-white when pure, and firm. The metal is corrosion-resistant. The catalytic properties of the six platinum family metals are outstanding (a mixture of hydrogen and oxygen explodes in the presence of platinum). For this catalytic property platinum is used in catalytic converters, incorporated in automobile exhaust systems, as well as tips of spark plugs. Platinum's wear- and tarnish-resistance characteristics are well suited for making fine jewelry. Platinum is more precious than gold. The price of platinum cha ...

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Platinum, Platinum - Notable characteristics, Platinum - Applications, Platinum - History, Platinum - Occurrence, Platinum - Isotopes, Platinum - Precautions, Platinum - Rarity and Color

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Phosphors are usually made from a suitable host material, to which an activator is added. The best known type is a copper-activated zinc sulfide and the silver-activated zinc sulfide (zinc sulfide silver). The host materials are typically oxides, sulfides, selenides, halides or silicates of zinc, cadmium, manganese, aluminum, silicon, or various rare earth metals. The activators prolong the emission time (afterglow). In turn, other materials (eg. nickel) can be used to quench the afterglow and shorten the decay part of ...

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Phosphor, Phosphor - Materials, Phosphor - Glow in the dark toys, Phosphor - Radoactive light sources, Phosphor - Electroluminescence, Phosphor - White LEDs, Phosphor - Cathode ray tubes, Phosphor - Fluorescent lamps, Phosphor - Detergents, Phosphor - Various

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Palladium is a soft steel-white metal that resembles platinum, doesn't tarnish in air, and is the least dense and has the lowest melting point of the platinum group metals. It is soft and ductile when annealed and greatly increases its strength and hardness when it is cold-worked. Palladium is chemically attacked by sulfuric and nitric acid but dissolves slowly in hydrochloric acid. This metal al ...

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Palladium, Palladium - Notable characteristics, Palladium - Applications, Palladium - History, Palladium - Occurrence, Palladium - Isotopes

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Tungsten is a metal with a wide range of uses, the largest of which is as tungsten carbide (W2C, WC) in cemented carbides. Cemented carbides (also called hardmetals) are wear-resistant materials used by the metalworking, mining, petroleum and construction industries. Tungsten is widely used in light bulb and vacuum tube filaments, as well as electrodes, because it can be drawn into very thin metal wires that have a high melting point. Other uses; A high melting point also makes tungsten suitable for space-oriented and ...

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Tungsten, Tungsten - Notable characteristics, Tungsten - Applications, Tungsten - History, Tungsten - Biological role, Tungsten - Occurrence, Tungsten - Compounds, Tungsten - Aqueous polyoxoanions, Tungsten - Isotopes

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Since technetium is unstable, only minute traces occur naturally in the Earth's crust as a spontaneous fission product of uranium. In 1999 David Curtis (see above) estimated that a kilogram of uranium contains 1 nanogram (1×10−9 g) of technetium. Extraterrestrial technetium was found in some red giant stars (S-, M-, and N-types) that contain an absorption line in their spectrum indicating the presence of this element. In contrast with the rare natural occurrence, bulk quantities of technetium-99 are produced each year fr ...

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Technetium, Technetium - Notable characteristics, Technetium - Applications, Technetium - Nuclear medicine, Technetium - Industrial, Technetium - History, Technetium - Pre-discovery search, Technetium - Disputed 1925 discovery, Technetium - Official discovery and later history, Technetium - Occurrence and production, Technetium - Part of radioactive waste, Technetium - Reductive immobilization, Technetium - Chemical means, Technetium - Biological means, Technetium - Isotopes, Technetium - Stability of technetium isotopes, Technetium - Precautions

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Mercury was known to the ancient Chinese and Hindus and was found in Egyptian tombs that date from 1500 BC In China, India and Tibet, mercury use was thought to prolong life, heal fractures, and maintain generally good health. The ancient Greeks used mercury in ointments and the Romans used it in cosmetics. By 500 BC mercury was used to make amalgams with other metals. The Indian word for alchemy is Rassayana which means ‘the way of mercury.’ Alchemists often thought of mercury as the first matter from which all metals were ...

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Mercury element, Mercury element - Applications, Mercury element - History, Mercury element - Dentistry, Mercury element - Medicine, Mercury element - Mineral occurrence, Mercury element - Compounds, Mercury element - Isotopes, Mercury element - Occurrence in the environment, Mercury element - Health and Environmental Effects, Mercury element - Precautions and regulation, Mercury element - Occupational exposure, Mercury element - Mercury in fish, Mercury element - Release of mercury into the environment, Mercury element - Mercury and aluminum

Read more here: » Mercury element: Encyclopedia II - Mercury element - History