Transcript platinum - MT KMUTT

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Platinum is the most important of the group of elements called the
platinum metals, the other members of which are ruthenium, rhodium,
palladium, osmium, and iridium. Platinum metals were probably used in
alloyed forms in ancient Greece and Rome and were first mentioned in
European literature in the early 16th century. The separation of the other
platinum metals from platinum and from each other was accomplished in
the early 19th century. Platinum is mined all over the world. In the late
1980s, the Soviet Union and South Africa were the leading producers.
Other leading producers are Canada, Colombia, and the United States.
Platinum is a chemical element with the chemical symbol Pt and an atomic
number of 78. Its name is derived from the Spanish term platina del Pinto, which is
literally translated into "little silver of the Pinto River“ It is dense, malleable,
ductile, precious, gray-white transition metal. Even though it has six naturally
occurring isotopes, platinum is one of the rarest elements in the Earth's crust and
has an average abundance of approximately 0.005 mg/kg. It occurs in some nickel
and copper ores along with some native deposits, mostly in South Africa, which
accounts for 80% of the world production.
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a member of the platinum group of elements, as well as of the group 10of the
periodic table of elements, platinum is generally unreactive. It exhibits a
remarkable resistance to corrosion, even at high temperatures, and as such is
considered a noble metal. As a result, platinum is often found chemically
uncombined as native platinum. Because it occurs naturally in the alluvial sands of
various rivers, it was first used by pre-ColumbianSouth American natives to
produce artifacts. It was referenced in European writings as early as 16th century,
but it was not until Antonio de Ulloapublished a report on a new metal of
Colombianorigin in 1748 that it became investigated by scientists.
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Platinum is used in catalytic converters, laboratory equipment, electrical contacts
and electrodes, platinum resistance thermometers, dentistry equipment, and
jewelry. Because only a few hundred tonnes are produced annually, it is a scarce
material, and is highly valuable and is a major precious metal commodity. Being a
heavy metal, it leads to health issues upon exposure to its salts, but due to its
corrosion resistance it is not toxic as a metal. Some of its compounds, most notably
cisplatin, are applied in chemotherapy against certain types of cancer.
Name: Platinum
Symbol: Pt
Atomic Number: 78
Group: 10
Period: 6
Atomic Mass: 195.078 amu
Melting Point: 1772.0 °C (2045.15 K, 3221.6 °F)
Boiling Point: 3827.0 °C (4100.15 K, 6920.6 °F)
Number of Protons/Electrons: 78
Number of Neutrons: 117
Classification: Transition Metal
Crystal Structure: Cubic
Density @ 293 K: 21.45 g/cm3
Color: silverish
Atomic Radius : 1.83Å
Atomic Volume: 9.1cm3/mol
Covalent Radius: 1.3Å
Cross Section (Thermal Neutron Capture) σa/barns: 0.96
Crystal Structure: Cubic face centered
Electron Configuration: 1s2 2s2p6 3s2p6d10 4s2p6d10f14 5s2p6d9 6s1
Electrons per Energy Level: 2,8,18,32,17,1
Ionic Radius: 0.625Å
Filling Orbital: 5d9
Number of Electrons (with no charge): 78
Number of Neutrons (most common/stable nuclide): 117
Number of Protons: 78
Oxidation States: 2,4
Valence Electrons: 5d9 6s1
platinum
Number of Energy Levels: 6
First Energy Level: 2
Second Energy Level: 8
Third Energy Level: 18
Fourth Energy Level: 32
Fifth Energy Level: 17
Sixth Energy Level: 1
Isotope
Half Life
Pt-188
10.2 days
Pt-190
6.0E11 years
Pt-191
2.96 days
Pt-192
Stable
Pt-193
60.0 years
Pt-193m
4.33 days
Pt-194
Stable
Pt-195
Stable
Pt-195m
4.02 days
Pt-196
Stable
Pt-197
18.3 hours
Pt-197m
1.59 hours
Pt-198
Stable
Characteristic
Isotopes
Occurrence
Compounds
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PHYSICAL
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As a pure metal, platinum is silverywhite, lustrous, ductile, and malleable.
It does not oxidize at any temperature,
although it is corroded by halogen,
cyanides, sulfur, and caustic alkalis.
Platinum is insoluble in hydrochloric
and nitric acid, but dissolves in aqua
regia to form chloroplatinic acid,
H2PtCl6. Platinum's resistance to wear
and tarnish is well suited for making
fine jewelry. The metal has an
excellent resistance to corrosion and
high temperature and has stable
electrical properties. All of these
characteristics have been exploited
for industrial applications.
CHEMICAL
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Platinum dissolves in hot aqua regia
The most common oxidation states of
platinum are +2 and +4. The +1 and
+3 oxidation states are less common,
and are often stabilized by metal
bonding in bimetallic (or
polymetallic) species. As is expected,
tetracoordinate platinum(II)
compounds tend to adopt 16-electron
square planar geometries. While
elemental platinum is generally
unreactive, it dissolves in aqua regia
to give soluble hexachloroplatinic
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Platinum has six naturally occurring isotopes: 190Pt, 192Pt, 194Pt, 195Pt, 196Pt,
and 198Pt. The most abundant of these is 195Pt, comprising 33.83% of all
platinum. It is the only stable isotope with a non-zero spin; with a spin of
1/ , 195Pt satellite peaks are often observed in 1H and 31P NMR
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spectroscopy (i.e. Pt-phosphine and Pt-alkyl complexes). 190Pt is the least
abundant at only 0.01%. Of the naturally occurring isotopes, only 190Pt is
unstable, though it decays with a half-life of 6.5×1011 years. 198Pt
undergoes alpha decay, but because its half-life is estimated at longer
than 3.2×1014 years, it is considered stable. Platinum also has 31 synthetic
isotopes ranging in atomic mass from 166 to 202, making the total number
of known isotopes 37. The least stable of these is 166Pt with a half-life of
300 µs, while the most stable is 193Pt with a half-life of 50 years. Most
platinum isotopes decay by some combination of beta decay and alpha
decay. 188Pt, 191Pt, and 193Pt decay primarily by electron capture. 190Pt and
198Pt have double beta decay paths.
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A native platinum nugget, Kondyor
mine, Khabarovsk Krai
Platinum is an extremely rare metal,occurring at a
concentration of only 0.005 ppm in the Earth's crust.It is
sometimes mistaken for silver (Ag). Platinum is often
found chemically uncombined as native platinum and
alloyed with iridium as platiniridium. Most often the native
platinum is found in secondary deposits; platinum is
combined with the other platinum group metals in alluvial
deposits. The alluvial deposits used by pre-Columbian
people in the Chocó Department, Colombia are still a
source for platinum group metals. Another large alluvial
deposit is in the Ural Mountains, Russia, and it is still
mined.
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In nickel and copper deposits, platinum group metals occur as sulfides (e.g.,
(Pt,Pd)S), tellurides (e.g., PtBiTe), antimonides (PdSb), and arsenides (e.g.,
PtAs2), and as end alloys with nickel or copper. Platinum arsenide, sperrylite
(PtAs2), is a major source of platinum associated with nickel ores in the Sudbury
Basin deposit in Ontario, Canada. At Platinum, Alaska, about 545,000 troy ounces
had been mined between 1927 and 1975. The mine ceased operations in
1990.The rare sulfide mineral cooperite, (Pt,Pd,Ni)S, contains platinum along with
palladium and nickel. Cooperite occurs in the Merensk Reef within the Bushveld
complex, Gauteng, South Africa.
In 1865, chromites were identified in the Bushveld region of South Africa, followed
by the discovery of platinum in 1906. The largest known primary reserves are in
the Bushveld complex in South Africa. The large copper–nickel deposits near
Norilsk in Russia, and the Sudbury Basin, Canada, are the two other large
deposits. In the Sudbury Basin, the huge quantities of nickel ore processed make
up for the fact platinum is present as only 0.5 ppm in the ore. Smaller reserves can
be found in the United States, for example in the Absaroka Range in Montana. In
2009, South Africa was the top producer of platinum, with an almost 80% share,
followed by Russia at 11%.
Platinum exists in higher abundances on the Moon and in meteorites.
Correspondingly, platinum is found in slightly higher abundances at sites of bolide
impact on the Earth that are associated with resulting post-impact volcanism, and
can be mined economically; the Sudbury Basin is one such example.
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compounds
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halides
oxides
Other
compounds
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it serves as the precursor for many other platinum compounds. By itself, it has
various applications in photography, zinc etchings, indelible ink, plating, mirrors,
porcelain coloring, and as a catalyst.
Treatment of hexachloroplatinic acid with an ammonium salt, such as
ammonium chloride, gives ammonium hexachloroplatinate, which is relatively
insoluble in ammonium solutions. Heating this ammonium salt in the presence
of hydrogen reduces it to elemental platinum. Potassium hexachloroplatinate is
similarly insoluble, and hexachloroplatinic acid has been used in the
determination of potassium ions by gravimetry
When hexachloroplatinic acid is heated, it decomposes through platinum(IV)
chloride and platinum(II) chloride to elemental platinum, although the reactions
do not occur stepwise:
(H3O)2PtCl6·nH2O PtCl4 + 2 HCl + (n + 2) H2O
PtCl4 PtCl2 + Cl2
PtCl2 Pt + Cl2
All three reactions are reversible. Platinum(II) and platinum(IV) bromides are
known as well. Platinum hexafluoride is a strong oxidizer capable of oxidizing
oxygen.
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Platinum(IV) oxide, PtO2, also known as Adams' catalyst, is a black
powder which is soluble in KOH solutions and concentrated acids.
PtO2 and the less common PtO both decompose upon heating.
Platinum(II,IV) oxide, Pt3O4, is formed in the following reaction:
2 Pt2+ + Pt4+ + 4 O2− → Pt3O4
Platinum also forms a trioxide, where it is present in the +4
oxidation state.
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Unlike palladium acetate, platinum(II) acetate is not commercially
available. Where a base is desired, the halides have been used in
conjunction with sodium acetate. The use of platinum(II) acetylacetonate
has also been reported.
Several barium platinides have been synthesized in which platinum
exhibits negative oxidation states ranging from −1 to −2. These include
BaPt, Ba3Pt2, and Ba2Pt. Caesium platinide, Cs2Pt, has been shown to
contain Pt2−
anions. Platinum also exhibits negative oxidation states at surfaces
reduced electrochemically. The negative oxidation states exhibited by
platinum are unusual for metallic elements, and they are attributed to the
relativistic stabilization of the 6s orbitals.
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Zeise's salt, containing an ethylene ligand, was one of the first
organometallic compounds discovered. Dichloro(cycloocta-1,5diene)platinum(II) is a commercially available olefin complex, which
contains easily displaceable cod ligands ("cod" being an abbreviation of
1,5-cyclooctadiene). The cod complex and the halides are convenient
starting points to platinum chemistry.
Cisplatin, or cis-diamminedichloroplatinum(II) is the first of a series of
square planar platinum(II)-containing chemotherapy drugs, including
carboplatin and oxaliplatin. These compounds are capable of crosslinking
DNA, and kill cells by similar pathways to alkylating chemotherapeutic
agents.
Platinum atom
ADVANTAGE
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Always Natural colour
No corrosion and dissolve by acid
No rust and no melt by fire because it high
thermal more than gold
Platinum is rare. and because of its
remarkable properties, industry is
constantly finding new uses for it.
Platinum often moves in the opposite
direction of traditional investments, making
it a good way to stabilize the value of your
portfolio.
Platinum also can be attractive as a stand
alone investment.
Platinum is an excellent hedge against
inflation.
Platinum is one of the most liquid of all
investments. It is readily portable, easy to
store, and is recognized world-wide. It is
easily and discreetly bought and sold. It
can be easily converted to cash at any time.
LIMITATION
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Because it’s very strong
then harder to transform for
accessory
High cost
Platinum is primarily an industrial metal. It is a critical
material for many industries and is considered a
“strategic metal” by the US Government as a military
resource. It is estimated that about 20% of the
products purchased by modern consumers either
contain platinum or use it in production. Total demand
for platinum falls into eight broad categories
Automotive
• used in catalytic converters, spark plugs, and sensors
Chemical processing
• also as a general catalyst
Jewellery
• as a substitute for gold
glass
• Dies and process technology
Electrical/electronics
• for high-temperature and non-corrosive wires
• and contacts
Petroleum refining
• as a catalyst for crude oil cracking
Dental/Medical
• equipment and reconstructive
Investment
• bullion and coins
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Platinum, together with palladium and rhodium, are primary elements in
autocalysts that control vehicle exhausts emissions of hydro-carbons, carbon
monoxide, oxides of nitrogen and particulate. Autocatalysts convert most of
these emissions into less harmful carbon dioxide, nitrogen and water vapor.
Autocatalyst was forecast to account for almost 51% of total platinum demand
in 2006 (up from 25% in 2000).
Demand for platinum in autocatalysts started to increase significantly in the
seventies when clean air legislation was introduced in USA and Japan. Many
other countries followed this policy since then. However, in the 1990s, there
was a substitution from platinum to palladium in autocatalysts in the United
States, mainly due to its relatively lower cost and better performance in
autocatalysts. In Europe platinum was more widely used since it is an essential
element for diesel cars. Recent developments in the palladium market
together with technological advances have led to a switch back to platinum. In
recent years demand for platinum in autocatalysts has shown a considerable
growth in emerging countries that introduced new environmental legislation.
Demand for platinum in this application is expected to grow as stricter
emissions standards and regulations are approved.
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Platinum has become a very popular choice for modern jewellery, displacing
significant gold demand. Its hardness and durability allows it to be used in
purer form for secure stone settings. It is much superior to silver because of
its resistance to oxidation and discoloration. Its rich hue and reflectivity
enhances the brilliance of precious stones. Platinum is hypoallergenic which
makes it the best jewellery choice for people who suffer reactions from other
metals or 14k (alloyed) gold.
Platinum jewellery has been particularly popular with Asian consumers. Many
Asians feel that platinum has a more pleasing contrast with the Asian skin
colour than other metals. Other ethnic groups have started to purchase
platinum for similar reasons. Platinum also seems to have a marketing
advantage over gold or silver. Products and awards with the “Platinum”
designation are typically considered superior those labelled “Gold” or
“Silver”. This gives platinum jewellery items additional prestige.
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Platinum is used as a catalytic agent in processing of nitric acid, fertilizers,
synthetic fibers, and a variety of other materials. In catalytic processes, the
catalyst material is not consumed and can be recycled for future use. This
makes chemical demand for platinum quite volatile. Platinum is essential in
many of these processes and there are few satisfactory substitutes.
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Platinum is used in the production of hard disk drive coatings and fiber optic
cables. The increasing number of personal computers will have a positive
effect on platinum demand in the future. Other applications include
thermocouples that measure temperature in the glass, steel and
semiconductor industries or infra-red detectors for military and commercial
applications. It is also used in multi-layer ceramic capacitors and crucibles to
grow single crystals
 Platinum
is used in glassmaking equipment.
It is used in the manufacturing of fiberglass
reinforced plastic and of glass for liquid
crystal displays (LCD). In this context, some
new developments in the production of LCD
glass and cathode ray tubes, both used in
computer screens should be mentioned.
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This is another use for the catalytic properties of platinum. The petroleum
industry uses the metal in a mesh or gauze form in crude oil refining. Platinum
use in petroleum refining follows global demand for refined crude oil
products. Other technologies exist to perform crude oil separation but
catalytic processes using platinum and palladium are much more
environmentally friendly. As more refineries are built and updated, expect
platinum use in petroleum refining to rise. Also, less developed countries are
being pressured to improve environmental standards. Refineries in those
areas will ultimately be converted to catalytic processing, further boosting
demand for platinum group metals. As in other catalytic processes, platinum is
not consumed and is aggressively recycled and reused. This makes petroleum
industry demand highly volatile.
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Platinum is seen as an attractive investment vehicle and as a good way of
hedging assets against inflation. This attraction for platinum investment is
spreading worldwide and is based on platinum relative scarcity, its historical
price performance and unique fundamentals. Investing in platinum may be
done in futures and options or in bars, ingots and bullion coins like the
American Eagle, the Australian Koala or the Canadian Maple Leaf among
others.
Medical
Platinum is used in anti-cancer drugs and in implants. It is also
used neurosurgical apparatus and in alloys for dental restorations.
Spark plugs
Most vehicles in North America use platinum-tipped spark plugs. In Europe
higher durability requirements have led to an increase in the amount of
platinum used in spark plugs.
Fuel cells are devices that generate electric power. They are being
developed as an alternative to internal combustion engines in vehicles.
Most fuel cells apply proton exchange membrane technology producing
energy from hydrogen and oxygen by using platinum catalysts. The use of
fuel cells brings about environmental and economic advantages. They are
more energy efficient and produce negligible pollution. All the major
automotive companies, lead by Daimler-Chrysler, are planning to have fuel
cell powered light vehicles by 2003-2004. Actually, there are already some
fuel cell heavy vehicles working. However, the doubt remains since every
vehicle using a fuel cell will be one that will not use a conventional
autocatalyst. The effect on platinum demand will depend on which device
uses more platinum. Present research is focusing on improving
performance and reducing costs of fuel cells. Fuel cells can also provide
stationary power generation. The use of platinum in fuel cells seems to be
one of the platinum applications with best prospects for future demand.
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