physical features
Pure platinum is a silvery white metal with luster and ductility. Its ductility is the highest among all pure metals, better than that of gold, silver and copper, but lower than that of gold.
Platinum metal has strong corrosion resistance, is very stable at high temperature, and its electrical properties are also very stable. It will not oxidize at any temperature, but will be corroded by various halogens, cyanide, sulfur and caustic soda. Platinum is insoluble in hydrochloric acid and nitric acid, but soluble in hot water will produce chloroplatinic acid (H _ H _ H2PtCl6 _ 6).
All these physical properties make platinum a widely used metal in industry. Platinum can also be used to make jewelry, because it can resist corrosion and keep luster.
chemical property
The most common oxidation states of platinum are +2 and +4. +0 and +3 of +65438 platinum are rare, and the metal bond in bimetallic (or polymetallic) compounds can improve its stability. Tetracoordinated platinum (II) compounds usually have a planar quadrilateral structure formed by 16 electrons.
Platinum metal has low reactivity, but when it is dissolved in hot water, chloroplatinic acid (H _ 2PTCl _ 6): Pt+4HNO3? + 6 HCl → H2PtCl6？ + 4 NO2？ + 4 H2O
Platinum is a soft acid, so it has chemical affinity with sulfur, such as dimethyl sulfoxide (DMSO); Scientists have discovered many kinds of DMSO complexes.
App application
Of the 265,438+08 tons of platinum sold in 2065,438+04, 98 tons were used for automobile emission control devices (45%), 74.7 tons were used for jewelry (34%), 20.0 tons were used for chemical production and petroleum refining (9.2%), and 5.85 tons were used for electrical applications such as manufacturing hard disks (2.7%).
The remaining 28.9 tons are used for various other minor applications, such as medicine and biomedicine, glass manufacturing equipment, investment, electrodes, anticancer drugs, oxygen sensors, spark plugs and turbine engines.
1, catalyst
The most common use of platinum is as a catalyst for chemical reactions, usually platinum black. Platinum powder has been used as a catalyst since the beginning of19th century, when it was used to catalyze the ignition of hydrogen. Its most important application is as a catalytic converter in automobiles, which can completely burn unburned hydrocarbons with low concentration in tail gas into carbon dioxide and water vapor.
In the petroleum industry, platinum is also used as a catalyst in many separation processes, especially in the catalytic reforming of straight-run naphtha into high octane gasoline rich in aromatic compounds.
2. precious metals investment
Platinum is a precious metal? Commodity; The ISO currency code of its gold and silver is XPT. Coins, gold bars and ingots are traded or collected. Because of its inertness, platinum can be used in jewelry, usually 90-95% alloy.
It is used for this purpose because of its prestige and inherent gold and silver value. Jewelry industry publications suggest that jewelers try to improve the value of platinum products by taking tiny surface scratches (which they call "copper rust") as an ideal feature.
Refer to the above? Baidu Encyclopedia-Platinum