What is the chemical symbol for platinum



properties
Generally
Name, symbol, atomic number Platinum, Pt, 78
seriesTransition metals
Group, period, block10, 6, d
Look gray-white
Mass fraction of the earth's envelope 5 · 10-7 %
Atomic
Atomic mass 195,084 u
Atomic radius (calculated) 135 (177) pm
Covalent radius 138 pm
Van der Waals radius 175 pm
Electron configuration [Xe] 4f145d96s1
Electrons per energy level 2, 8, 18, 32, 17, 1
Work function 5.7-6.35 eV
1. Ionization energy 870 kJ / mol
2. Ionization energy 1791 kJ / mol
Physically
Physical state firmly
Modifications
Crystal structure Cubic area-centered
density 21.45 g / cm3
Mohs hardness 4,3
magnetismparamagnetic
Melting point 2045 K (1772 ° C)
boiling point 4100 K (3827 ° C)
Molar volume 9,1 · 10-6 m3/ mol
Heat of evaporation 510 kJ / mol
Heat of fusion 19.6 kJ / mol
Vapor pressure

0.0312 Pa at 2045 K.

Speed ​​of sound 2680 m / s at 293.15 K.
Specific heat capacity 130 J / (kg K)
Electric conductivity 9,66 · 106S / m
Chemically
Oxidation states 0, +2, +4, +6
Oxides (basicity) PtO, PtO2 (slightly basic)
Normal potential 1.118 V (Pt2+ + 2e- → Pt)
Electronegativity 2.28 (Pauling scale)
Isotopes
isotopeNHt1/2ZMZE MeVZP
188platinum

{syn.}

10.2 dε0,507188Ir
189platinum

{syn.}

10.87 hε1,971189Ir
190platinum

0,01 %

6,5 · 1011aα3,249186Os
191Pt

{syn.}

2.96 dε1,019191Ir
192Pt

0,79 %

Stable
193Pt

{syn.}

50 aε0,057193Ir
194Pt

32,9 %

Stable
195Pt

33,8 %

Stable
196Pt

25,3 %

Stable
197Pt

{syn.}

19.8915 hβ0,719197Au
198Pt

7,2 %

Stable
199Pt

{syn.}

30.80 minβ1,702199Au
200Pt

{syn.}

12.5 hβ0,660200Au
NMR properties
  Spinγ in
rad · T−1· S−1
E. fL. at
W = 4.7 T
in MHz
195Pt 1/2 5,751 · 107 0,00994 43
safety instructions
Hazardous substance labeling
R and S phrases R:
S:
As far as possible and customary, SI units are used.
Unless otherwise noted, the data given apply to standard conditions.


platinum is a chemical element in the Periodic Table of the Elements with the symbol Pt and atomic number 78.

Platinum is a heavy, malleable, ductile, noble, gray-white transition metal. The precious metal is very corrosion-resistant and is used to manufacture jewelry, vehicle catalysts, laboratory equipment, dental implants and contact materials.

 

history

The name is derived from the Spanish word platina, the negative diminutive of plata "Silver", from. The first European mention comes from the Italian humanist Julius Caesar Scaliger. He describes a mysterious white metal that evaded all attempts at melting. A more detailed description of the properties can be found in a report by Antonio de Ulloa published in 1748.

Platinum was probably first used in ancient Egypt around 3000 BC. The British researcher Sir William Matthew Flinders Petrie (1853–1942) discovered ancient Egyptian jewelry in 1895 and found that small amounts of platinum were also used.

Platinum was also used by the Indians of South America. It was simply found in the extraction of gold dust in the washing gold as an accompaniment and could not be explicitly separated. The blacksmiths at that time unconsciously exploited the fact that native platinum grains with gold dust can be welded well in the embers of a charcoal fire fanned with bellows, the gold acting like a solder and, through repeated forging and heating, a relatively homogeneous, light color in the forging heat let produce deformable metal alloy. This could not be melted again and was just as durable as gold, but of a whitish-silver-like color. A platinum content of around 15 percent already results in a light gray color. However, pure platinum was still unknown.

In the 17th century, platinum became a major problem in the Spanish colonies as an annoying material when prospecting for gold. Inexperienced with such things, unexplained how one was particularly far from the West, full of superstition, speculation and magic, one thought of "immature" gold and threw it back into the rivers of Ecuador. After all, it already had the same specific weight as gold and did not tarnish even in the fire, only the beautiful yellow color was still missing. As a result, it has been used to falsify the same. The Spanish government then issued an export ban. She even considered dumping all the platinum she had received to date in the sea to forestall and deter platinum smuggling and counterfeiting.

The alchemy of the 18th century was called for, because the differentiation from pure gold and the extraction turned out to be extremely difficult with the techniques of the time. But interest was aroused. In 1748 Antonio de Ulloa published a detailed report on the properties of this metal. In 1750, the English doctor William Brownrigg made purified platinum powder.

The Swedish scientist Theophil Scheffer classified platinum as a precious metal in 1751. Platinum had become valuable. A metal for kings, it was only a matter of time before the rulers of Europe noticed it. Due to the high melting temperature of 1772 ° C, platinum could not be processed in pure form for a long time. By alloying with a few percent tin (and also copper), at least platinum powder could be melted and cast into a homogeneous material at the maximum temperatures of 1200–1500 degrees that could be generated at that time. The first attempts to melt clean platinum were made at the focal point of a large concave mirror. It was not until 1772 that the discovery of oxygen made it possible to produce sufficiently hot fire. But pure, malleable metal, apart from small quantities, could still not be reliably produced. For example, the precious metal willingly absorbs carbon in the welding heat of the coal fire and then becomes brittle.

Around 1780, Louis XVI, King of France decreed that only the king could own platinum. His court goldsmith Marc Etienne Janety created wonderful objects for him, including a complete set with cobalt blue enamel. In order not to stand behind his French competitor, Charles III commissioned. from Spain, also a platinum enthusiast, in 1788 appointed the jeweler Francisco Alonso to make a splendid platinkelch. The goblet 30 centimeters high and two kilograms became Pope Pius VI. presented.

In 1795, France was the first country in the world to introduce the metric system for weights and measures. Platinum was selected as a suitable metal for this task - it is durable, does not wear out and therefore does not change the standardized dimensions. The original of this platinum cylinder, the original kilogram, is now in the Bureau International des Poids et Mesures (BIPM), near Paris.

Numerous discoveries and scientific advances in the course of the Enlightenment enabled the British scientist William Hyde Wollaston to develop a useful method for producing pure, ductile platinum in 1803. The platinum metal palladium is discovered. In Russia, abundant platinum deposits were discovered in the Urals in 1819. At the same time, interest in this material arose and other platinum accompanying metals such as rhodium and iridium were isolated. Advances in chemistry and the mastery of electricity opened up new areas of application for the heat-resistant precious metal in the 19th century. From 1828 to 1845, under Tsar Nicholas I, the platinum ruble became a means of payment in Russia. In 1856 the German pharmacist and chemist Wilhelm Carl Heraeus melted platinum in an oxyhydrogen flame and founded the platinum melt "W.C. Heraeus" with this technology. At the end of the 19th century, around 1000 kg of metal were processed. In 1866 the rich diamond deposits were discovered in Kimberley in South Africa, and a few years later the platinum deposits too.

In 1884, Peter Carl Fabergé, the jeweler of the Russian Tsar Alexander III, made a sumptuous egg with platinum applications. The Russian Fabergé egg is immediately “en vogue”. In Europe, there is an unprecedented rush for platinum jewelry with diamonds. At the end of the 19th century, the Belle Epoque, emperors, kings, tsars and maharajas adorn themselves with platinum. Spain's King, Charles IV, commissioned a 'Chambre en platine' in his summer residence, the Palacido Real in Aranjuez. It was made using fine woods with circuit board inserts.

At the beginning of the 20th century, Louis Cartier made jewelry entirely from platinum for the first time in order to underline the brilliance of the diamonds. His platinum craftsmanship is unrivaled and King Edward VII of England hails him as "the jeweler of kings and king of jewelers". The Maharajah of Patiala has Cartier tiaras and elaborate turban jewelry made from the white precious metal. Precious fabrics are woven with platinum threads, among other things. The price of platinum was eight times higher than that of gold.

Germany, a world leader in chemical engineering at the turn of the century, developed important chemical-technological synthesis processes with the help of catalysts. The Haber-Bosch process developed by BASF in 1910 is introduced. In the Ostwald process, the resulting ammonia is converted to nitrogen oxides on a large scale using platinum-rhodium catalysts, the end products of which, the nitrates, are important starting substances for artificial fertilizers, explosives and many other chemicals. In 1912, white gold came onto the market as a replacement for jewelry platinum. In the same year the Titanic sinks and New York's high society mourns as a result. Black and white is trendy and “bijoux de deuil” (mourning jewelry). Of course, platinum is often used as a white metal for this.

Hans Merensky, a German geologist, discovered the enormous platinum deposits near Johannesburg in South Africa in 1924. This is where the modern platinum industry begins.

The sound film is invented and Hollywood stars like Jean Harlow, Marlene Dietrich and Mae West confidently display platinum jewelery in public. Platinum conquered Hollywood, Frank Capra made the film in 1931 Platinum blonde (Warnings are given against blondes).

For the coronation of King George VI. Elizabeth Bowes-Lyon (mother of Queen Elizabeth II) wears an elegant platinum crown in 1937 that shows the Koh-I-Noor diamond. Edward, now Duke of Windsor, pampers his wife Wallis Simpson with platinum jewelry from Cartier. Wallis, Duchess of Windsor, jewelry expert par excellence, publicly states that platinum jewelry is the only one that is really suitable for evening receptions. For her collection, the Duchess received the “Panthère de Cartier” brooch with blue sapphires and diamonds, today a much-copied jewelry classic.

During the Second World War, platinum was an essential raw material for the war effort on both sides of the Atlantic because of its importance for nitrogen oxide synthesis and thus the production of explosives, and the production of platinum jewelry was therefore prohibited.

The states with the greatest funding

By far the most important platinum producer is South Africa, followed by the Russian Federation (especially the northern Urals).

rank country Delivery rates
(in t)
1 South Africa 140
2 Russian Federation 70
3 Canada 18,5
4 United States 4,2
5 Colombia 1,4
6 Zimbabwe 1,3

Extraction and manufacture