Platinum
The element platinum carries the symbol Pt and holds atomic number 78 in the periodic table. It exists as six naturally occurring isotopes that define its nuclear behavior. The most abundant of these is platinum-195, which makes up 33.83% of all natural platinum found on Earth. This specific isotope possesses a non-zero spin value of one-half, making it uniquely useful for certain types of NMR spectroscopy. Scientists observe satellite peaks in spectra when studying platinum-phosphine complexes due to this property. Another isotope, platinum-190, represents only 0.012% of natural abundance yet undergoes alpha decay with a half-life of 4.83 years. This radioactive decay generates very low activity measured at 16.8 Bq/kg of natural platinum. Researchers utilize this decay pattern in isotope geology studies even though it does not directly date rocks. Thirty-eight synthetic isotopes exist ranging from mass 165 to 208, bringing the total known count to 44. The most stable radioisotope among these has a half-life of 50 years. Most platinum isotopes decay through combinations of beta decay or electron capture processes.
Platinum concentration in Earth's crust measures just 0.005 parts per million, making it extremely rare. Native platinum nuggets appear in alluvial deposits within river sands across various regions. Pre-Columbian people extracted metal from alluvial deposits in Colombia's Chocó Department centuries ago. Modern mining operations target secondary deposits where native platinum accumulates alongside other metals. The Merensky Reef layer in South Africa contains approximately 75% of the world's known platinum reserves. Hans Merensky discovered this large supply in 1924 within the Bushveld Igneous Complex. In 2010, South Africa produced almost 77% of global platinum output while Russia contributed 13%. World production reached 170,000 kilograms that same year according to geological surveys. The Sudbury Basin deposit in Ontario, Canada holds platinum arsenide minerals called sperrylite. This mineral associates with nickel ores and represents another major source region. Platinum exists at sites of bolide impact on Earth due to post-impact volcanism creating economic mines. The Stillwater Mine in Montana produces sulfidic serpentinite containing platinum-palladium ore. A mine near Platinum, Alaska operated between 1927 and 1975 before closing permanently in 1990. Advanced groundwater studies recently identified new potential deposits in Tamil Nadu, India.
Platinum does not corrode even when exposed to high temperatures or air over extended periods. Heated metal wires lose weight faster in oxygen environments compared to vacuum conditions. Scientists suggest a thin surface film forms that decomposes above 500 degrees Celsius. The most common oxidation states for platinum are plus two and plus four. Less common states include plus one and plus three, often stabilized by bimetallic bonding. Tetracoordinate platinum compounds adopt square planar geometries holding sixteen electrons. Chlorine, bromine, iodine, and sulfur attack elemental platinum while fluorine reacts vigorously at room temperature. Platinum dissolves in hot aqua regia but remains insoluble in hydrochloric or nitric acid alone. Hexachloroplatinic acid serves as the precursor for many other platinum compounds used in photography and plating. Heating this acid decomposes it through platinum chloride stages back to elemental platinum. Adams catalyst consists of platinum oxide appearing as a black powder soluble in potassium hydroxide solutions. Barium platinides contain dark-red transparent crystals with platinum anions showing unusual negative oxidation states. Zeise's salt represents one of the first organometallic compounds ever discovered containing ethylene ligands.
Archaeologists found traces of platinum in gold from ancient Egyptian burials dating before 200 CE. A small box decorated with gold-platinum hieroglyphics appeared in the burial of Shepenupet II. Native Americans near Esmeraldas, Ecuador created white gold-platinum alloy artifacts using sintering techniques. The La Tolita Culture practiced platinum-working between 1500 BCE and 200 CE according to archaeological associations. European writers first mentioned platinum in 1557 when Julius Caesar Scaliger described an unknown noble metal. Spanish authorities treated platinum as impurity in gold and issued decrees forbidding its adulteration. Antonio de Ulloa published his report on Colombian platinum in 1748 after eight years traveling through Colombia and Peru. Charles Wood sent samples to William Brownrigg in Jamaica during 1741 for further investigation. Brownrigg presented detailed accounts to the Royal Society in 1750 noting platinum's high melting point. Henrik Scheffer published a scientific description calling it white gold in 1752 while fusing ore with arsenic. Karl von Sickingen made malleable platinum by hammering finely divided material in 1772. Franz Achard constructed the first platinum crucible in 1784 using arsenic fusion methods. King Louis XV declared platinum fit only for kings due to its scarcity and intrinsic value.
Ninety-eight tonnes of platinum went into vehicle emissions control devices out of 218 total sold in 2014. Catalytic converters complete combustion of unburned hydrocarbons from exhaust into carbon dioxide and water vapor. Platinum powder catalyzed hydrogen ignition experiments starting in the early nineteenth century. Petroleum industries use platinum catalysts to reform straight-run naphthas into higher-octane gasoline rich in aromatics. Adams catalyst specifically hydrogenates vegetable oils for commercial food production. Fuel cells utilize platinum as a catalyst for oxygen reduction reactions enabling green hydrogen production. Proton exchange membrane technologies require platinum-based systems for electric vehicle adoption. The German scientist Gerhard Ertl won the Nobel Prize in Chemistry in 2007 for determining molecular mechanisms of carbon monoxide oxidation over platinum surfaces. Platinum resistance thermometers define temperature scales using wires with 99.999% chemical purity. These instruments measure temperatures up to approximately one thousand degrees Celsius in laboratory settings. Platinum-cobalt alloys containing three parts platinum create relatively strong permanent magnets for industrial applications. Ships, pipelines, and steel piers employ platinum-based anodes to prevent corrosion damage.
Cisplatin represents the first square planar platinum compound used as chemotherapy treatment for certain cancers. Other drugs including carboplatin and oxaliplatin follow similar pathways crosslinking DNA to kill cancer cells. Side effects of cisplatin include nausea, vomiting, hair loss, tinnitus, hearing loss, and kidney toxicity. Platinum exposure shows no adverse effects on animal life due to its low reactivity levels. Medical implants like breast prosthetics and joint replacements use silicone rubber components manufactured with platinum catalysts. The Food and Drug Administration reviewed these materials finding no evidence suggesting toxicity inside living bodies. Short-term exposure to platinum salts may cause irritation of eyes, nose, and throat tissues. Long-term occupational exposure can trigger respiratory and skin allergies among workers handling compounds. OSHA standards limit air concentration to two micrograms per cubic meter averaged over eight-hour shifts. Platinum drugs treat testicular carcinomas, ovarian tumors, melanoma, lung cancers, myelomas, and lymphomas. Dental prostheses and medical instruments frequently incorporate platinum for their inertness during heating procedures.
The international prototype meter defined length from 1889 until 1960 using a platinum-iridium alloy bar. A cylinder of the same alloy measured mass for the kilogram definition until May 2019. Platinum resistance thermometers serve as one of four types defining the International Temperature Scale of 1990. Bullion carries ISO currency code XPT allowing global trading of coins, bars, and ingots. Jewelry markets sell platinum at .999 or .9995 fine purity levels emphasizing prestige value. Rolex, Vacheron Constantin, Patek Philippe, and Breitling manufacture select watches using platinum cases. Prices sometimes exceed gold values during periods of sustained economic stability and growth. Dubai's famous gold souk saw buyers turn to platinum when gold prices surpassed it in major markets. Costco sells platinum bars on its website as of 2024 according to company records. The Crown of Queen Elizabeth The Queen Mother features a frame made entirely of platinum metal. This was the first British crown constructed from this particular material for her coronation. Musical albums selling over one million copies receive platinum certification credits in the United States. Advertisers associate platinum with exclusivity creating platinum debit cards with greater privileges than gold versions.
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Common questions
What is the atomic number and symbol of platinum?
Platinum carries the symbol Pt and holds atomic number 78 in the periodic table. It exists as six naturally occurring isotopes that define its nuclear behavior.
Where are the largest known reserves of platinum located on Earth?
The Merensky Reef layer in South Africa contains approximately 75% of the world's known platinum reserves. Hans Merensky discovered this large supply in 1924 within the Bushveld Igneous Complex.
When did European writers first mention platinum in historical records?
European writers first mentioned platinum in 1557 when Julius Caesar Scaliger described an unknown noble metal. Antonio de Ulloa published his report on Colombian platinum in 1748 after eight years traveling through Colombia and Peru.
How does platinum function in modern vehicle emissions control devices?
Ninety-eight tonnes of platinum went into vehicle emissions control devices out of 218 total sold in 2014. Catalytic converters complete combustion of unburned hydrocarbons from exhaust into carbon dioxide and water vapor using platinum powder catalysts.
What is cisplatin used for in medical treatments today?
Cisplatin represents the first square planar platinum compound used as chemotherapy treatment for certain cancers. Platinum drugs treat testicular carcinomas, ovarian tumors, melanoma, lung cancers, myelomas, and lymphomas by crosslinking DNA to kill cancer cells.