Platinum

Platinum - Pt

CAS: 7440-06-4
Description: Silver-white metal
Classification: Transition Metal
Date of Discovery: 1735
Discoverer: Ulloa / Wood
Name Origin: Spanish platina, "little silver"

Atomic Number: 78
Number of Neutrons: 117
Atomic Mass:
Melting Point:
Boiling Point:
Density (293 K): 21.45 g/cm³
Atomic volume: 9.10 cm³/mol
Electrical resistivity: 0.0966 10^-6/cm

Thermal conductivity: 0.716 W/cmK
Enthalpy of atomization: 565 kJ/mol (est.)
Enthalpy of vaporization: 510.0 kJ/mol
Enthalpy of fusion: 19.60 kJ/mol
Specific heat capacity: 0.13 J/gK

Energy levels: 2-8-18-32-17-1
Electron configuration: [Xe]4f ¹⁴5d⁹6s¹
Crystal Structure: Cubic face centered
Atomic radius: 1.83 Å
Covalent radius: 1.30 Å
Oxidation States: +1(?), +2, +3, +4
Electronegativity, Pauling: 2.28
Electron affinity: 2.128 eV
First ionization energy: 9.0 eV
2nd ionization energy: 18.563 eV
3rd ionization energy:
Polarizability: 6.5 10^-24cm³

Isotope	Natural Abundance	Atomic Mass	Half-life	Decay Mode	Spin
¹⁶⁸Pt	167.9880
¹⁶⁹Pt	168.9864	3 ms
¹⁷⁰Pt	169.9816	6 ms
¹⁷¹Pt	170.9811	0.03 s
¹⁷²Pt	171.97730	0.10 s		0+
¹⁷³Pt	172.9765	0.34	⁺, EC;	0+
¹⁷⁴Pt	173.97281	0.89 s	⁺, EC;	0+
¹⁷⁵Pt	174.9723	2.5 s	⁺, EC;
¹⁷⁶Pt	175.9690	6.3 s	⁺, EC;	0+
¹⁷⁷Pt	176.9685	11 s	EC;
¹⁷⁸Pt	177.9649	21 s	EC;	0+
¹⁷⁹Pt	178.9653	33 s	⁺, EC;
¹⁸⁰Pt	179.9632	52 s	⁺, EC;	0+
¹⁸¹Pt	180.9632	51 s	⁺, EC
¹⁸²Pt	181.9613	2.7 m	⁺, EC	0+
^183mPt	43 s	⁺; IT	(7/2-)
¹⁸³Pt	182.9617	7 m	⁺, EC
¹⁸⁴Pt	183.9599	17.3 m	⁺, EC
^185mPt	33 m	⁺, EC	1/2-
¹⁸⁵Pt	184.9607	1.18 h	⁺, EC	(9/2+)
¹⁸⁶Pt	185.95943	2.0 h	⁺, EC	0+
¹⁸⁷Pt	186.9607	2.35 h	⁺, EC	3/2
¹⁸⁸Pt	187.95940	10.2 d	EC	0+
¹⁸⁹Pt	188.96083	10.9 h	⁺, EC
¹⁹⁰Pt	0.01(1)	189.95993	6.5 x 10¹¹ y	0+
¹⁹¹Pt	190.961684	2.96 d	EC	(3/2-)
¹⁹²Pt	0.79(6)	191.961035	Stable	0+
^193mPt	4.33 d	IT	13/2+
¹⁹³Pt	192.962984	60 y	EC	(1/2-)
¹⁹⁴Pt	32.9(6)	193.962663	Stable	0+
^195mPt	4.02 d	IT	13/2+
¹⁹⁵Pt	33.8	194.964774	Stable	1/2-
¹⁹⁶Pt	25.3(6)	195.964934	Stable	0+
^197mPt	1.590 h	IT; ^-	13/2+
¹⁹⁷Pt	196.967323	18.3 h	^-	1/2-
¹⁹⁸Pt	7.2(2)	197.967875	Stable	0+
^199mPt	13.6 s	IT	13/2+
¹⁹⁹Pt	198.970576	30.8 m	^-	(5/2-)
²⁰⁰Pt	199.97142	12,5 h	^-	0+
²⁰¹Pt	200.9745	2.5 m	^-	(5/2-)
²⁰²Pt	1.8 d
Discovered in South America by Ulloa in 1735 and by Wood in 1741. The metal was used by pre-Columbian Indians. Platinum occurs native, accompanied by small quantities of iridium, osmium, palladium, ruthenium, and rhodium, all belonging to the same group of metals. These are found in the alluvial deposits of the Ural mountains, of Columbia, and of certain western American states. Sperrylite (PtAs₂), occurring with the nickel-bearing deposits of Sudbury, Ontario, is the source of a considerable amount of metal. The large production of nickel offsets there being only one part of the platinum metals in two million parts of ore. Platinum is a beautiful silvery-white metal, when pure, and is malleable and ductile. It has a coefficient of expansion almost equal to that of soda-lime-silica glass, and is therefore used to make sealed electrodes in glass systems. The metal does not oxidize in air at any temperature, but is corroded by halogens, cyanides, sulfur, and caustic alkalis. It is insoluble in hydrochloric and nitric acid, but dissolves when they are mixed as aqua regia, forming chloroplatinic acid (H₂PtCl₆), an important compound. Natural platinum contains six isotopes, one of which, ¹⁹⁰Pt, is radioactive with a long half-life. Thirty- five other radioactive isotopes and isomers are recognized. The metal is extensively used in jewelry, wire, and vessels for laboratory use, and in many valuable instruments including thermocouple elements. It is also used for electrical contacts, corrosion-resistant apparatus, and in dentistry. Platinum-cobalt alloys have magnetic properties. One such alloy made of 76.7% Pt and 23.3% Co, by weight, is an extremely powerful magnet that offers a B-H (max) almost twice that of Alnico V. Platinum resistance wires are used for constructing high-temperature electric furnaces. The metal is used for coating missile nose cones, jet engine fuel nozzles, etc., which must perform reliably for long periods of time at high temperatures. The metal, like palladium, absorbs large volumes, of hydrogen, retaining it at ordinary temperatures but giving it up at red heat. In the finely divided state platinum is an excellent catalyst, having long been used in the contact process for producing sulfuric acid. It is also used as a catalyst in cracking petroleum products. There is also much current interest in the use of platinum as a catalyst in fuel cells and in its use as antipollution devices for automobiles. Platinum anodes are extensively used in cathodic protection systems for large ships and ocean-going vessels, pipelines, steel piers, etc. Pure platinum wire will glow red hot when placed in the vapor of methyl alcohol. It acts here as a catalyst, converting the alcohol to formaldehyde. This phenomenon has been used commercially to produce cigarette lighters and hand warmers. Hydrogen and oxygen explode in the presence of platinum. LINKS: European emission standards to boost precious metals use Heatin' with Hydrogen Native Platinum PLATINUM technology - News Return Sources for the information on this website include: Lide, David R., ed. CRC Handbook of Chemistry and Physics, 78th Ed., 1997-1998.

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