In the periodic table of the chemical elements, six metallic elements -
all transition metals - are clustered together and lie in the d-block
(the d-block in the periodic table refers to groups 8, 9, and 10,
periods 5 and 6). These six elements are collectively referred to as the
platinum group metals.
Of this group of metals, platinum is considered the most widely traded, as it is extensively used in the following: catalytic converters; dental alloys and other dentistry equipment; electrical conductors; resistive thermal devices, laboratory dishes and such other equipment capable of resisting chemical attack even in high temperature; and, of course, jewelry.
As a transition element, platinum is gray-white in appearance. Often because of this, it is mistaken for silver. Its other physical characteristics include its being malleable, ductile, and dense. But while platinum is generally resistant to corrosion, it is corroded by certain elements, such as cyanides (potassium cyanide or sodium cyanide), caustic alkalis, sulfur, and any of the five halogens (astatine, bromine, chlorine, fluorine, and iodine).
The following lists some of the properties of platinum:
* Chemical Symbol: Pt
* Atomic Number: 78
* Category (as an element): Transition Metal
* Group/ Period/ Block (in the Periodic Table): 10/ 6/ d
* Atomic Weight: 195.084 g.mol-1
* Electron Configuration: [Xe] 4f14 5d9 6s1
* Density (near room temperature): 21.45 g.cm-3
* Liquid Density (at melting point): 19.77 g.cm-3
* Melting Point: 1768.3°C, 3214.9°F, 2041.4°K
* Boiling Point: 3825°C, 6917°F, 4098°K
* Heat of Fusion: 22.17 kJ.mol-1
* Heat of Vaporization: 469 kJ.mol-1
* Oxidation States: 6, 5, 4, 3, 2, 1, -1, -2
* Electronegativity: 2.28 (Pauling scale)
* Atomic Radius: 139 picometre
* Covalent Radius: 136±5 picometre
* Van der Waals Radius: 175 picometre
* Ionization Energies: 870 kJ.mol-1 (first), 1791 kJ.mol-1 (second)
Platinum is known to occur as only three thousandth parts-per notation (0.003 ppm) in the Earth's crust. This makes it an extremely rare metal.
Compared to gold, platinum is more precious, although its price is considered more volatile. One of the reasons for this is that its demand is driven by industrial uses or applications. For example, its price tends to be double that of gold's when world economy is stable, but significantly goes down in times of economic uncertainty.
Because it's wear-resistant and does not tarnish, platinum is highly valued by jewelers, especially watchmakers. In 2008, its price went up to as high as 2,252 U.S. dollars per troy ounce.
Being rare and, therefore, very precious, platinum has been made synonymous to things that are considered "of the highest quality". We hear for instance of a platinum debit card holder enjoying a wide range of privileges; or of a platinum award being handed out to a music album that has sold over a million copies.
Platinum's rarity and preciousness has been so pronounced in fact as early as the Eighteenth century, that then French King Louis XV even made a declaration making platinum "the only metal fit for a king".