dysprosium

Aluminium chloride (AlCl3) is a compound of aluminium and chlorine. The anhydrous material has a very interesting structure: despite being the halide of a highly electropositive metal, its bonding is principally covalent. This is seen in the fact that it has a low melting and boiling point (it sublimes at 178 °C), and it conducts electricity poorly in the liquid state[1], unlike ionic halides such as sodium chloride. It exists in the solid state as a six-coordinate layer lattice. This melts to a four-coordinate ...

Including:

• Aluminium chloride - Chemical Properties
• Aluminium chloride - Preparation
• Aluminium chloride - Uses
• Aluminium chloride - Precautions
• Aluminium chloride - Suppliers/Manufacturers

Read more here: » Aluminium chloride: Encyclopedia - Aluminium chloride

In physics, magnetism is one of the phenomena by which materials exert an attractive or repulsive force on other materials. Magnetism - Magnetic materials. Some well known materials that exhibit easily detectable magnetic properties are iron, some steels, and the mineral lodestone; however, all materials are influenced to one degree or another by the presence of a magnetic field, although in most cases the influence is too small to detect without special equipment.

The Friedel-Crafts reaction[3] is the major use for aluminium chloride, for example in the preparation of anthraquinone (for the dyestuffs industry) from benzene and phosgene.[1] In the general Friedel-Crafts reaction[3] an acyl chloride or alkyl halide reacts with an aromatic system as shown: With benzene derivatives, the major product is the para isomer. The alkylation reaction has many associated problems (see Friedel-Crafts), so it is less widely used than the acylation reaction. For ...

See also:

Aluminium chloride, Aluminium chloride - Chemical Properties, Aluminium chloride - Preparation, Aluminium chloride - Uses, Aluminium chloride - Precautions, Aluminium chloride - Suppliers/Manufacturers

Read more here: » Aluminium chloride: Encyclopedia II - Aluminium chloride - Uses

Iridium satellite - The constellation. The Iridium system requires 66 active satellites in orbit to complete its constellation, with spare satellites in orbit to fill in in case of failure. Satellites are in low Earth orbit at a height of approximately 485 miles. Satellites communicate with neighbouring satellites via intersatellite links. Each satellite can have four intersatellite links: two to neighbors fore and aft in the same orbital plane, and two to satellites in neighboring planes to either side. The ...

See also:

Iridium satellite, Iridium satellite - History, Iridium satellite - Present status, Iridium satellite - Flares, Iridium satellite - Technical details, Iridium satellite - The constellation, Iridium satellite - The satellites, Iridium satellite - Earth base-stations, Iridium satellite - Patents, Iridium satellite - Quotes

Read more here: » Iridium satellite: Encyclopedia II - Iridium satellite - Technical details

Dysprosium(III) chloride can be prepared as a yellow aqueous solution by reaction of either dysprosium metal or dysprosium(III) carbonate and hydrochloric acid. 2 Dy(s) + 6 HCl(aq) → 2 DyCl3(aq) + 3 H2(g) Dy2(CO3)3(s) + 6 HCl(aq) → 2 DyCl3(aq) + 3 CO2(g) + 3 H2O(l) Anhydrous DyCl3 can be made by dehydration of the hydrate either by slowly heating to 400 °C with 4-6 equivalents of ammonium chlo ...

See also:

DysprosiumIII chloride, DysprosiumIII chloride - Chemical properties, DysprosiumIII chloride - Preparation, DysprosiumIII chloride - Uses, DysprosiumIII chloride - Precautions, DysprosiumIII chloride - Suppliers/Manufacturers

Read more here: » DysprosiumIII chloride: Encyclopedia II - DysprosiumIII chloride - Preparation

Magnetism - Electromagnets. Electromagnets are useful in cases where a magnet must be switched on or off; for instance, large cranes to lift junked automobiles. For the case of electric current moving through a wire, the resulting field is directed according to the "right hand rule." If the right hand is used as a model, and the thumb of the right hand points along the wire from positive towards the negative side ("conventional current", the reverse of the direction of actual movement of electrons), then t ...

See also:

Magnetism, Magnetism - Magnetic materials, Magnetism - Physics of magnetism, Magnetism - Charged particle in a magnetic field, Magnetism - Magnetic dipoles, Magnetism - Magnetic monopoles, Magnetism - Atomic magnetic dipoles, Magnetism - Types of magnets, Magnetism - Electromagnets, Magnetism - Permanent Magnets, Magnetism - SI magnetism units, Magnetism - Other magnetism units

Read more here: » Magnetism: Encyclopedia II - Magnetism - Types of magnets

Occurring as a minor accessory mineral, xenotime is found in pegmatites and other igneous rocks, as well as gneisses rich in mica and quartz. Associated minerals include biotite and other micas, chlorite group minerals, quartz, zircon, certain feldspars, analcime, anatase, brookite, rutile, siderite, and apatite. Xenotime is also known to be diagenetic: It may form as minute grains or as extremely thin (less than 10 µ) coatings on detrital zircon grains in siliciclastic sedimentary rocks. The importance of these diagenetic xenotime deposits in the radiometric dating of sedimentary rock ...

See also:

Xenotime, Xenotime - Properties, Xenotime - Occurrence

Read more here: » Xenotime: Encyclopedia II - Xenotime - Occurrence

Magnetism - Electromagnets. Electromagnets are useful in cases where a magnet must be switched on or off; for instance, large cranes to lift junked automobiles. For the case of electric current moving through a wire, the resulting field is directed according to the "right hand rule." If the right hand is used as a model, and the thumb of the right hand points along the wire from positive towards the negative side ("conventional current", the reverse of the direction of actual movement of electrons), then t ...

See also:

Magnetism, Magnetism - Magnetic materials, Magnetism - Physics of magnetism, Magnetism - Charged particle in a magnetic field, Magnetism - Magnetic dipoles ., Magnetism - Magnetic monopoles ., Magnetism - Atomic magnetic dipoles, Magnetism - Types of magnets, Magnetism - Electromagnets, Magnetism - Permanent Magnets, Magnetism - SI magnetism units, Magnetism - Other magnetism units, Magnetism - Footnotes

Read more here: » Magnetism: Encyclopedia II - Magnetism - Types of magnets

Normally, magnetic fields are seen as dipoles, having a "South pole" and a "North pole"; terms dating back to the use of magnets as compasses, interacting with the Earth's magnetic field to indicate North and South on the globe. A magnetic field contains energy, and physical systems stabilize into the configuration with the lowest energy. Therefore, when placed in a magnetic field, a magnetic dipole tends to align itself in opposed polarity to that field, thereby canceling the net field strength as much as possible and lowering ...

See also:

Magnetism, Magnetism - Magnetic materials, Magnetism - Physics of magnetism, Magnetism - Charged particle in a magnetic field, Magnetism - Magnetic dipoles ., Magnetism - Magnetic monopoles ., Magnetism - Atomic magnetic dipoles, Magnetism - Types of magnets, Magnetism - Electromagnets, Magnetism - Permanent Magnets, Magnetism - SI magnetism units, Magnetism - Other magnetism units, Magnetism - Footnotes

Read more here: » Magnetism: Encyclopedia II - Magnetism - Magnetic dipoles .

The physical cause of the magnetism of objects, as distinct from electrical currents, is the atomic magnetic dipole. Magnetic dipoles, or magnetic moments, result on the atomic scale from the two kinds of movement of electrons. The first is the orbital motion of the electron around the nucleus; this motion can be considered as a current loop, resulting in an orbital dipole magnetic moment along the axis of the nucleus. The second, much stronger, source of electronic magnetic moment is due to a quantum mechanical property called the spin dipole magnetic moment (although current quantum mechanical theory states that elect ...

See also:

Magnetism, Magnetism - Magnetic materials, Magnetism - Physics of magnetism, Magnetism - Charged particle in a magnetic field, Magnetism - Magnetic dipoles ., Magnetism - Magnetic monopoles ., Magnetism - Atomic magnetic dipoles, Magnetism - Types of magnets, Magnetism - Electromagnets, Magnetism - Permanent Magnets, Magnetism - SI magnetism units, Magnetism - Other magnetism units, Magnetism - Footnotes

Read more here: » Magnetism: Encyclopedia II - Magnetism - Atomic magnetic dipoles

Contrary to normal experience, some theoretical physics models predict the existence of magnetic monopoles. Paul Dirac observed in 1931 that, because electricity and magnetism show a certain symmetry, just as quantum theory predicts that individual positive or negative electric charges can be observed without the opposing charge, isolated South or North magnetic poles should be observable. In practice, however, although charged particles like protons and electrons can be easily isolated as individual electrical charges, magnetic south and no ...

See also:

Magnetism, Magnetism - Magnetic materials, Magnetism - Physics of magnetism, Magnetism - Charged particle in a magnetic field, Magnetism - Magnetic dipoles ., Magnetism - Magnetic monopoles ., Magnetism - Atomic magnetic dipoles, Magnetism - Types of magnets, Magnetism - Electromagnets, Magnetism - Permanent Magnets, Magnetism - SI magnetism units, Magnetism - Other magnetism units, Magnetism - Footnotes

Read more here: » Magnetism: Encyclopedia II - Magnetism - Magnetic monopoles .

When a charged particle moves through a magnetic field B, it feels a force F given by the cross product: where is the electric charge of the particle is the velocity vector of the particle is the magnetic field Because this is a cross product, the force is perpendicular to both the motion of the particle and the magnetic field. It follows that the magnetic force does no work on the particle; it may change the direction of the par ...

See also:

Magnetism, Magnetism - Magnetic materials, Magnetism - Physics of magnetism, Magnetism - Charged particle in a magnetic field, Magnetism - Magnetic dipoles ., Magnetism - Magnetic monopoles ., Magnetism - Atomic magnetic dipoles, Magnetism - Types of magnets, Magnetism - Electromagnets, Magnetism - Permanent Magnets, Magnetism - SI magnetism units, Magnetism - Other magnetism units, Magnetism - Footnotes

Read more here: » Magnetism: Encyclopedia II - Magnetism - Charged particle in a magnetic field

The system is being used extensively by the U.S. Department of Defense for its communication purposes through the DoD Gateway in Hawaii. The commercial Gateway in Tempe, Arizona provides voice, data and paging services for commercial customers on a global basis. Typical customers include maritime, aviation, government, the petroleum industry, scientists, and frequent world travelers. Iridium Satellite LLC claims to have approximately 137,500 subscribers as of September 30, 2005, which is a 22% increase from the third quarter 2004. Revenue for the nine months ended September 30, 2005 was u ...

See also:

Iridium satellite, Iridium satellite - History, Iridium satellite - Present status, Iridium satellite - Flares, Iridium satellite - Technical details, Iridium satellite - The constellation, Iridium satellite - The satellites, Iridium satellite - Earth base-stations, Iridium satellite - Patents, Iridium satellite - Quotes

Read more here: » Iridium satellite: Encyclopedia II - Iridium satellite - Present status

Normally, magnetic fields are seen as dipoles, having a "South pole" and a "North pole"; terms dating back to the use of magnets as compasses, interacting with the Earth's magnetic field to indicate North and South on the globe. A magnetic field contains energy, and physical systems stabilize into the configuration with the lowest energy. Therefore, when placed in a magnetic field, a magnetic dipole tends to align itself in opposed polarity to that field, thereby canceling the net field strength as much as possible and lowering ...

See also:

Magnetism, Magnetism - Magnetic materials, Magnetism - Physics of magnetism, Magnetism - Charged particle in a magnetic field, Magnetism - Magnetic dipoles, Magnetism - Magnetic monopoles, Magnetism - Atomic magnetic dipoles, Magnetism - Types of magnets, Magnetism - Electromagnets, Magnetism - Permanent Magnets, Magnetism - SI magnetism units, Magnetism - Other magnetism units

Read more here: » Magnetism: Encyclopedia II - Magnetism - Magnetic dipoles

When a charged particle moves through a magnetic field B, it feels a force F given by the cross product: where is the electric charge of the particle is the velocity vector of the particle is the magnetic field Because this is a cross product, the force is perpendicular to both the motion of the particle and the magnetic field. It follows that the magnetic force does no work on the particle; it may change the direction of the par ...

See also:

Magnetism, Magnetism - Magnetic materials, Magnetism - Physics of magnetism, Magnetism - Charged particle in a magnetic field, Magnetism - Magnetic dipoles, Magnetism - Magnetic monopoles, Magnetism - Atomic magnetic dipoles, Magnetism - Types of magnets, Magnetism - Electromagnets, Magnetism - Permanent Magnets, Magnetism - SI magnetism units, Magnetism - Other magnetism units

Read more here: » Magnetism: Encyclopedia II - Magnetism - Charged particle in a magnetic field

Contrary to normal experience, some theoretical physics models predict the existence of magnetic monopoles. Paul Dirac observed in 1931 that, because electricity and magnetism show a certain symmetry, just as quantum theory predicts that individual positive or negative electric charges can be observed without the opposing charge, isolated South or North magnetic poles should be observable. In practice, however, although charged particles like protons and electrons can be easily isolated as individual electrical charges, magnetic south and no ...

See also:

Magnetism, Magnetism - Magnetic materials, Magnetism - Physics of magnetism, Magnetism - Charged particle in a magnetic field, Magnetism - Magnetic dipoles, Magnetism - Magnetic monopoles, Magnetism - Atomic magnetic dipoles, Magnetism - Types of magnets, Magnetism - Electromagnets, Magnetism - Permanent Magnets, Magnetism - SI magnetism units, Magnetism - Other magnetism units

Read more here: » Magnetism: Encyclopedia II - Magnetism - Magnetic monopoles

The physical cause of the magnetism of objects, as distinct from electrical currents, is the atomic magnetic dipole. Magnetic dipoles, or magnetic moments, result on the atomic scale from the two kinds of movement of electrons. The first is the orbital motion of the electron around the nucleus; this motion can be considered as a current loop, resulting in an orbital dipole magnetic moment along the axis of the nucleus. The second, much stronger, source of electronic magnetic moment is due to a quantum mechanical property called the spin dipole magnetic moment (although current quantum mechanical theory states that elect ...

See also:

Magnetism, Magnetism - Magnetic materials, Magnetism - Physics of magnetism, Magnetism - Charged particle in a magnetic field, Magnetism - Magnetic dipoles, Magnetism - Magnetic monopoles, Magnetism - Atomic magnetic dipoles, Magnetism - Types of magnets, Magnetism - Electromagnets, Magnetism - Permanent Magnets, Magnetism - SI magnetism units, Magnetism - Other magnetism units

Read more here: » Magnetism: Encyclopedia II - Magnetism - Atomic magnetic dipoles

Aluminium chloride is a powerful Lewis acid, capable of forming stable Lewis acid-base adducts with even weak Lewis bases such as benzophenone or mesitylene[3]. Not surprisingly it forms AlCl4- in the presence of chloride ion. In water, partial hydrolysis forms HCl gas or H3O+, as described in the overview above. Aqueous solutions behave similarly to other aluminium salts containing hydrated Al3+ ions- for example giving a gelatinous precipitate of aluminium hydroxide upon react ...

See also:

Aluminium chloride, Aluminium chloride - Chemical Properties, Aluminium chloride - Preparation, Aluminium chloride - Uses, Aluminium chloride - Precautions, Aluminium chloride - Suppliers/Manufacturers

Read more here: » Aluminium chloride: Encyclopedia II - Aluminium chloride - Chemical Properties

Iridium communications service was launched on November 1, 1998 and went into Chapter 11 bankruptcy on August 13, 1999. The first Iridium call was made by then-Vice President of the United States Al Gore. Its financial failure was largely due to insufficient demand for the service. The increased coverage of terrestrial cellular networks (e.g. GSM) and the rise of roaming agreements between cellular providers proved to be fierce competition. The cost of service was also prohibitive for many users, despite the continuous world-wide cove ...

See also:

Iridium satellite, Iridium satellite - History, Iridium satellite - Present status, Iridium satellite - Flares, Iridium satellite - Technical details, Iridium satellite - The constellation, Iridium satellite - The satellites, Iridium satellite - Earth base-stations, Iridium satellite - Patents, Iridium satellite - Quotes

Read more here: » Iridium satellite: Encyclopedia II - Iridium satellite - History