The specifications for the U.S. Army Air Corps Type A-2 regulation summer flying jacket, adopted in 1931 and the most familiar among all leather flight jackets, stated that it should be made of horsehide tanned to seal brown. However, initially, oxidation during the dying process caused the jackets to end up russet (a lighter, reddish brown) in color. Later in the decade, they were able to prevent oxidation during dying, and the jackets produced were a proper seal brown. Seal brown is one of the school colors of Brown University Seal brown is one of the ...

See also:

Seal brown, Seal brown - Usage

Read more here: » Seal brown: Encyclopedia II - Seal brown - Usage

Because of the extreme toxicity of its oxide, osmium is rarely used in its pure state, and is instead often alloyed with other metals that are used in high wear applications. Osmium alloys are very hard and along with other platinum group metals is almost entirely used in alloys employed in the tips of fountain pens, phonograph needles, instrument pivots, and electrical contacts. Osmium tetroxide has been used in fingerprint detection and in staining fatty tissue for microscope slides. As a strong oxidant it cross-links lipids thus fi ...

See also:

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

Read more here: » Osmium: Encyclopedia II - Osmium - Applications

AuCl3 exists as a dimer both as a solid and as a vapour; the bromide AuBr3 follows the same pattern. This is similar (but not identical) to the tetrahedral dimers formed by AlCl3 and FeCl3. The bonding in AuCl3 is mainly covalent, reflecting the high oxidation state and relatively high electronegativity (for a metal) of the gold. ...

See also:

GoldIII chloride, GoldIII chloride - Structure, GoldIII chloride - Chemical properties, GoldIII chloride - Preparation, GoldIII chloride - Uses, GoldIII chloride - Precautions, GoldIII chloride - Suppliers/Manufacturers

Read more here: » GoldIII chloride: Encyclopedia II - GoldIII chloride - Structure

Plutonium is silvery in pure form, but has a yellow tarnish when oxidized. Peculiarly, the metal goes through phases of contraction as its temperature is increased. The heat given off by alpha particle emission makes plutonium warm to the touch in reasonable quantities; larger amounts can boil water. It displays four ionic oxidation states in aqueous solution: Pu3+ (blue lavender) Pu4+ (yellow brown) PuO2+ (pink orange) PuO+ (thought to be pink; this i ...

See also:

Plutonium, Plutonium - Notable characteristics, Plutonium - Applications, Plutonium - History, Plutonium - Occurrence, Plutonium - Manufacture, Plutonium - Compounds, Plutonium - Allotropes, Plutonium - Isotopes, Plutonium - Precautions

Read more here: » Plutonium: Encyclopedia II - Plutonium - Notable characteristics

Acid-base reaction theories - Lavoisier's definition. The first scientific definition was proposed by the French chemist Antoine Lavoisier. Since Lavoisier's knowledge of strong acids was mainly restricted to oxoacids, which tend to contain central atoms in high oxidation states surrounded by oxygen, such as HNO3 and H2SO4, and since he was not aware of the true composition of the hydrohalic acids, HCl, HBr, and HI, he defined acids in terms of their containing oxygenSee also:

Acid-base reaction theories, Acid-base reaction theories - Common acid-base theories, Acid-base reaction theories - Lavoisier's definition, Acid-base reaction theories - The Arrhenius definition, Acid-base reaction theories - The protonic Brønsted-Lowry definition, Acid-base reaction theories - The solvent-system definition, Acid-base reaction theories - The electronic Lewis definition, Acid-base reaction theories - Other acid-base theories, Acid-base reaction theories - The Usanovich definition

Read more here: » Acid-base reaction theories: Encyclopedia II - Acid-base reaction theories - Common acid-base theories

Since 1892 the yellowish, monoclinic mineral baddeleyite had been the only natural form of zirconium oxide known. Being of rare occurrence it had little economic importance. The extremely high melting point of zirconia (2750°C) posed a hurdle to controlled single-crystal growth, as no existing crucible could hold it in its molten state. However, stabilization of zirconium oxide had been realized early on, with the synthetic product stabilized zirconia introduced in 1930. Although cubic, it was in the form of a polycrystalline ceramic: it was made use of as a refractory material, highly resistant to ch ...

See also:

Cubic zirconia, Cubic zirconia - Technical aspects, Cubic zirconia - History, Cubic zirconia - Synthesis, Cubic zirconia - Innovations, Cubic zirconia - CZ versus diamond

Read more here: » Cubic zirconia: Encyclopedia II - Cubic zirconia - History

Chlorites are salts of chlorous acid. How does the chlorite anion fit within the overall scheme of chlorine based anions? In general, chlorine can assume oxidation states of -1, +1, +3, +5, or +7 corresponding to the anions Cl-, ClO-, ClO2-, ClO3-, or ClO4-, respectively, known as chloride, hypochlorite, chlorite, chlorate, and perchlorate respectively.) The Chlorite anion is but one out ...

See also:

Chlorite, Chlorite - Definition, Chlorite - Examples, Chlorite - Dicussion, Chlorite - Manufacture, Chlorite - Usage

Read more here: » Chlorite: Encyclopedia II - Chlorite - Dicussion

Common oxidation states of iron include: the Iron(-II) state, Fe2- (e.g. Fe(CO)42-,Fe(CO)2(NO)2. the Iron(0) state, Fe(CO)5, Fe(PF3)5. the Iron(I) state, [Fe(H2O)5NO]2+. the Iron(II) state, Fe2+, previously ferrous is very common. the Iron(III) state, Fe3+, previously ferric, is also very common, for exam ...

See also:

Iron, Iron - Notable characteristics, Iron - Applications, Iron - History, Iron - Occurrence, Iron - Extraction from ore, Iron - Compounds, Iron - Isotopes, Iron - Biological role, Iron - Precautions

Read more here: » Iron: Encyclopedia II - Iron - Compounds

Common oxidation states of iron include: the Iron(-II) state, Fe2- (e.g. Fe(CO)42-,Fe(CO)2(NO)2. the Iron(0) state, Fe(CO)5, Fe(PF3)5. the Iron(I) state, [Fe(H2O)5NO]2+. the Iron(II) state, Fe2+, previously ferrous is very common. the Iron(III) state, Fe3+, previously ferric, is also very common, for exam ...

See also:

Iron, Iron - Notable characteristics, Iron - Applications, Iron - History, Iron - Occurrence, Iron - Extraction from ore, Iron - Compounds, Iron - Biological role, Iron - Isotopes, Iron - Precautions

Read more here: » Iron: Encyclopedia II - Iron - Compounds

Silvery in appearance, neptunium metal is fairly chemically reactive and is found in at least three structural modifications: alpha-neptunium, orthorhombic, density 20.25 Mg/m3, beta-neptunium (above 280 °C), tetragonal, density (313 °C) 19.36 Mg/m3, and gamma-neptunium (above 577 °C), cubic, density (600 °C) 18 Mg/m3. This element has four ionic oxidation states while in solution: Np+3 (pale purple), analogous to the rare earth ion PmSee also:

Neptunium, Neptunium - Notable characteristics, Neptunium - History, Neptunium - Occurrence, Neptunium - Isotopes, Neptunium - Weapons applications

Read more here: » Neptunium: Encyclopedia II - Neptunium - Notable characteristics

Environment - current issues: air pollution resulting in acid rain in both the US and Canada; the US is the largest single emitter of carbon dioxide from the burning of fossil fuels; water pollution from runoff of pesticides and fertilizers; very limited natural fresh water resources in much of the western part of the country require careful management; desertification Environment - international agreements: party to: Air Pollution, Air Pollution-Nitrogen Oxides, Antarctic-Environmental Protocol, Antarctic Treaty, Climate Change, Enda ...

See also:

Geography of the United States, Geography of the United States - Area, Geography of the United States - Physical geography, Geography of the United States - Cultural regions, Geography of the United States - Climate, Geography of the United States - Natural resources, Geography of the United States - Environment, Geography of the United States - Public lands

Read more here: » Geography of the United States: Encyclopedia II - Geography of the United States - Environment

Many but not all hydrogenases contain nickel in addition to iron-sulfur clusters. Nickel centres are a common element in those hydrogenases whose function is to oxidise rather than evolve hydrogen. The nickel centre appears to undergo changes in oxidation state, and evidence has been presented that the nickel centre might be the active site of these enzymes. A nickel-tetrapyrrole coenzyme, Co-F430, is present in the methyl CoM reductase and in methanogenic bacteria. The tetrapyrrole is intermediate in structure between porphyrin and corrin. Changes in redox state, as well as changes in nickel ...

See also:

Nickel, Nickel - Notable characteristics, Nickel - Applications, Nickel - History, Nickel - Biological role, Nickel - Occurrence, Nickel - Extraction and Purification, Nickel - Compounds, Nickel - Isotopes, Nickel - Precautions, Nickel - Notes

Read more here: » Nickel: Encyclopedia II - Nickel - Biological role

There are two different approaches one can use when counting electrons, each arriving at the same total. The constituents (i.e. metal and ligands) can be regarded as ions, or as neutral species. Using ferrocene as an example, and using the neutral approach first, the iron atom has 8 valence electrons. Each of the two cyclopentadiene radicals contributes 5 electrons, totalling 10 electrons from the ligands. 10+8=18 Using the ionic approach, iron is taken in its common oxidation state Fe2+, c ...

See also:

Electron counting, Electron counting - Counting rules for ligands, Electron counting - Examples of the 18 VE rule, Electron counting - Weaknesses of the 18 VE rule

Read more here: » Electron counting: Encyclopedia II - Electron counting - Examples of the 18 VE rule

Lycopene is a terpene assembled from 8 isoprene units. The color of lycopene is due to its many conjugated carbon double bonds. Each double bond reduces the energy required for electrons to transition to higher energy states, allowing the molecule to absorb visible light of progressively shorter wavelengths. Lycopene absorbs most of the visible spectrum, so it appears red. If lycopene is oxidized (for example, by reacting with bleaches or acids), the double bonds between carbon atoms will be broken, cleaving the molecule into s ...

See also:

Lycopene, Lycopene - Structure, Lycopene - Food Coloring

Read more here: » Lycopene: Encyclopedia II - Lycopene - Structure

Image:Arghematiteore.jpg In the United States and Canada, almost all natural ore reserves are exhausted. Modern mines in Minnesota, Michigan, and Eastern Canada mine taconite. Taconite is a term to describe magnetite ore that is very hard and fine-grained. Taconite must be first processed into iron oxide pellets by crushing and magnetic separation of the magnetite to concentrate the iron to about 66% bef ...

See also:

Iron ore, Iron ore - Mining, Iron ore - Refining, Iron ore - Smelting, Iron ore - Contaminants

Read more here: » Iron ore: Encyclopedia II - Iron ore - Mining

A typical reaction of an SOD protein containing copper (and zinc) looks like this: Cu2+-SOD + O2- → Cu1+-SOD + O2 Cu1+-SOD + O2- + 2H+ → Cu2+-SOD + H2O2. In this reaction the oxidation state of the copper changes between +1 and +2. ...

See also:

Superoxide dismutase, Superoxide dismutase - Reaction, Superoxide dismutase - Types, Superoxide dismutase - General, Superoxide dismutase - Human, Superoxide dismutase - Physiology, Superoxide dismutase - Role in disease, Superoxide dismutase - Cosmetic uses

Read more here: » Superoxide dismutase: Encyclopedia II - Superoxide dismutase - Reaction

Pure elemental iron is virtually unknown on the surface of the Earth except as wüstite from meteorites and very rare forms of deep mantle xenoliths. Therefore, all sources of iron used by human industry exploit iron oxide minerals, the primary form which is used in industry being hematite. However, in some situations, more inferior iron ore sources have been used by industrialised societies when access to high-grade hematite ore was not available. This has included utilisation of taconite in the United State, particularly during Worl ...

See also:

Iron ore, Iron ore - Mining, Iron ore - Refining, Iron ore - Smelting, Iron ore - Contaminants

Read more here: » Iron ore: Encyclopedia II - Iron ore - Refining

Cobalt is a hard ferromagnetic silver-white element. The Curie temperature is of 1388 K with 1.6~1.7 Bohr magnetons per atom. It is frequently associated with nickel, and both are characteristic ingredients of meteoric iron. Mammals require small amounts of cobalt salts. Cobalt-60, an artificially produced radioactive isotope of cobalt, is an important radioactive tracer and cancer-treatment agent. Cobalt has a relative permeability two thirds that of iron. Metallic cobalt commonly presents a mixture of two crystallographic structures hcp and fcc with a transition temperature hcp→fcc of 722 K. Common oxidation states of ...

See also:

Cobalt, Cobalt - Notable characteristics, Cobalt - Applications, Cobalt - Use in medicine, Cobalt - History, Cobalt - Biological role, Cobalt - Occurrence, Cobalt - Compounds, Cobalt - Isotopes, Cobalt - Precautions

Read more here: » Cobalt: Encyclopedia II - Cobalt - Notable characteristics

The gradual darkening of the ink was due to the oxidation of the iron ions from ferrous (Fe++) to ferric (Fe+++) state by atmospheric oxygen. (For that reason, the liquid ink had to be stored in a well-stoppered bottle, and would become unusable after a time.) The ferric ions then reacted with the tannin or some derived compound (possibly gallic acid or pyrogallol) to form a polymeric organometallic compound. The gallol would then make strong and permanent chemical bonds with the proteins of the hide, by ...

See also:

Iron-gall nut ink, Iron-gall nut ink - Preparation and use, Iron-gall nut ink - Chemistry, Iron-gall nut ink - Demise, Iron-gall nut ink - Warning, Iron-gall nut ink - External link

Read more here: » Iron-gall nut ink: Encyclopedia II - Iron-gall nut ink - Chemistry

The odorless and tasteless thallium sulfate was widely used in the past as a rat poison and ant killer. In the United States and many other countries this use is no longer allowed due to safety concerns. Other uses: thallium sulfide's electrical conductivity changes with exposure to infrared light therefore making this compound useful in photocells. thallium bromide-iodide crystals have been used as infrared optical materials. thallium oxide has been used to manufacture glasses that have a high index of refract ...

See also:

Thallium, Thallium - Notable characteristics, Thallium - Applications, Thallium - History, Thallium - Occurrence, Thallium - Isotopes, Thallium - Precautions, Thallium - Famous uses

Read more here: » Thallium: Encyclopedia II - Thallium - Applications

Nuclear reprocessing - Bismuth phosphate. The bismuth phosphate process is a very old process which adds lots of material to the final highly active waste, it was replaced by solvent extraction processes. The process was designed to extract plutonium from aluminium clad uranium metal fuel. The fuel was declad by boiling it in caustic soda, after decladding the uranium metal was dissolved in nitric acid. The plutonium at this point is in the +4 oxidation state, it was then precipitated by the addition of bi ...

See also:

Nuclear reprocessing, Nuclear reprocessing - History, Nuclear reprocessing - Spent nuclear fuel, Nuclear reprocessing - Old Methods which are no longer used, Nuclear reprocessing - Bismuth phosphate, Nuclear reprocessing - Hexone or Redox, Nuclear reprocessing - Butex ββ'-dibutyoxydiethyl ether, Nuclear reprocessing - Current methods which are in use, Nuclear reprocessing - PUREX, Nuclear reprocessing - Possible methods for future use, Nuclear reprocessing - Aqueous methods, Nuclear reprocessing - Non aqueous methods, Nuclear reprocessing - Economics of reprocessing nuclear fuel, Nuclear reprocessing - list of nuclear reprocessing sites

Read more here: » Nuclear reprocessing: Encyclopedia II - Nuclear reprocessing - Old Methods which are no longer used

At room temperature, sulfur is a soft bright yellow solid. Although sulfur is infamous for its smell - frequently compared to rotten eggs - the odor is actually characteristic of hydrogen sulfide (H2S); elemental sulfur is odorless. It burns with a blue flame that emits sulfur dioxide, notable for its peculiar suffocating odor. Sulfur is insoluble in water but soluble in carbon disulfide and other nonpolar solvents. Common oxidation states of sulfur include −2, +2, +4 and +6. Sulfur forms stable c ...

See also:

Sulfur, Sulfur - Notable characteristics, Sulfur - Applications, Sulfur - Biological role, Sulfur - Environmental Impact, Sulfur - History, Sulfur - Occurrence, Sulfur - Compounds, Sulfur - Isotopes, Sulfur - Precautions, Sulfur - Spelling

Read more here: » Sulfur: Encyclopedia II - Sulfur - Notable characteristics