Platinum has the chemical symbol Pt and atomic number 78. It’s
a dense, malleable, ductile, highly unreactive, precious, grey-white transition
metal. Its name is derived from the Spanish term platina, which is literally
translated into "little silver”.
Platinum occurs in the wild as the pure element as well as alloyed with iridium, known as platiniridium. It is one of the rarest elements in the Earth's crust with an average abundance of approximately 5 μg/kg.
In addition to its high density, resistance to oxidation and other desirable qualities, platinum is remarkably chemically unreactive. For these reasons, a 90-10% alloy of platinum-iridium is still used as the International Prototype Kilogram. Originally, this prototype kilogram was made of pure platinum, but iridium was added to increase its hardness while retaining platinum's many desirable qualities.
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Platinum
is used in catalytic converters, laboratory equipment, electrical contacts and
electrodes, platinum resistance thermometers, dentistry equipment, and
jewellery. Being a heavy metal, it leads to health issues upon exposure to its
salts, but due to its corrosion resistance, it is not as toxic as some metals. Some
compounds containing platinum are applied in chemotherapy against certain types
of cancer.
Platinum;s resistance to wear and tarnish is well suited to its use in fine jewellery.
Platinum is obtained commercially as a by-product from nickel and copper mining and processing. As an example, of the 245 tonnes of platinum sold in 2010, 113 tonnes were used for vehicle emissions control devices (46%), 76 tonnes for jewellery (31%). The remaining 35.5 tonnes went to various other minor applications, such as investment, electrodes, anticancer drugs, oxygen sensors, spark plugs and turbine engines.
For more information visit:-
http://www.theguardian.com/science/grrlscientist/2013/jan/11/1?guni=Article:in%20body%20link
http://en.wikipedia.org/wiki/Platinum
Neodymium is a chemical element with the symbol Nd and atomic number 60. It is a soft silvery metal that tarnishes in air.
Like most metals, neodymium is a lustrous silvery white colour, and like its twin praseodymium,, it tarnishes rapidly in air so it must be stored under argon (as above) or oil. Like the other lanthanoids, it is a rare earth metal that is anything but rare. In fact, neodymium is exceedingly common -- almost as common as copper -- being the second most common of the rare earth elements in the Earth's crust, following cerium.
Neodymium compounds were first commercially used as glass dyes in 1927, and they remain a popular additive in glasses. The color of neodymium compounds—due to the Nd3+ ion—is often a reddish-purple but it changes with the type of lighting, due to fluorescent effects.
Its compounds have a variety of lovely colours -- pink, mauve, purple, violet, green -- that change based on the sort of lighting they are exposed to. For example, neodymium chloride hexahydrate, NdCl3·6H2O [see image courtesy of Walkerma (public domain)], is pink when exposed to sunlight (top) and a boring yellowish colour when exposed to fluorescent light (bottom).
Another chief use of neodymium is as the free pure element. It is used as a component in the alloys used to make high-strength neodymium magnets – powerful permanent magnets. These magnets are widely used in such products as microphones, professional loudspeakers, in-ear headphones, and computer hard disks, where low magnet mass or volume, or strong magnetic fields are required. Larger neodymium magnets are used in high power versus weight electric motors (for example in hybrid cars) and generators.
Neodymium magnets are often referred to as "supermagnets". And they are for a reason: a one gram neodymium supermagnet can hold up a 1.3 kg (2.8 lb) iron sphere!
Neodymium metal dust is a combustion and explosion hazard. Neodymium compounds, as with all rare earth metals, are of low to moderate toxicity; however its toxicity has not been thoroughly investigated. Neodymium dust and salts are very irritating to the eyes and mucous membranes, and moderately irritating to skin. Breathing the dust can cause lung embolisms, and accumulated exposure damages the liver.
Even relatively small neodymium magnets cause all sorts of damages, even those that are just a few centimetres square. They are dangerous to people with pacemakers. Bone fractures from flying magnets and crushing the tip off a finger are not uncommon.
Check out this video link too:-
Neodymium Magnet experiments
For more information visit:-
http://www.theguardian.com/science/grrlscientist/2012/apr/27/1?guni=Article:in%20body%20link
http://en.wikipedia.org/wiki/Neodymium
