Platinum

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Platinum
78Pt
Pd

Pt

Ds
iridiumplatinumgowd
Appearance
grayish white
General properties
Name, seembol, nummer platinum, Pt, 78
Pronunciation /ˈplætɨnəm/
Element category transeetion metal
Group, period, block 10, 6, d
Staundart atomic wicht 195.084
Electron confeeguration [Xe] 4f14 5d9 6s1
2, 8, 18, 32, 17, 1
Electron shells of platinum (2, 8, 18, 32, 17, 1)
History
Discovery Antonio de Ulloa (1735)
First isolation Antonio de Ulloa (1735)
Physical properties
Phase solid
Density (near r.t.) 21.45 g·cm−3
Liquid density at m.p. 19.77 g·cm−3
Meltin pynt 2041.4 K, 1768.3 °C, 3214.9 °F
Boilin pynt 4098 K, 3825 °C, 6917 °F
Heat o fusion 22.17 kJ·mol−1
Heat o vaporization 469 kJ·mol−1
Molar heat capacity 25.86 J·mol−1·K−1
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 2330 (2550) 2815 3143 3556 4094
Atomic properties
Oxidation states 6, 5, 4, 3, 2, 1, −1, −2, −3
(mildly basic oxide)
Electronegativity 2.28 (Pauling scale)
Ionization energies 1st: 870 kJ·mol−1
2nd: 1791 kJ·mol−1
Atomic radius 139 pm
Covalent radius 136±5 pm
Van der Waals radius 175 pm
Miscellanea
Crystal structure face-centered cubic
Platinum has a face-centered cubic crystal structure
Magnetic orderin paramagnetic
Electrical resistivity (20 °C) 105 nΩ·m
Thermal conductivity 71.6 W·m−1·K−1
Thermal expansion (25 °C) 8.8 µm·m−1·K−1
Speed o soond (thin rod) (r.t.) 2800 m·s−1
Tensile strength 125-240 MPa
Young's modulus 168 GPa
Shear modulus 61 GPa
Bulk modulus 230 GPa
Poisson ratio 0.38
Mohs hairdness 4–4.5
Vickers hairdness 549 MPa
Brinell hairdness 392 MPa
CAS registry nummer 7440-06-4
Most stable isotopes
Main article: Isotopes o platinum
iso NA hauf-life DM DE (MeV) DP
190Pt 0.014% 6.5×1011 y α 3.18 186Os
192Pt 0.782% >4.7×1016 y α - 188Os
193Pt syn 50 y ε - 193Ir
194Pt 32.967% 194Pt is stable wi 116 neutrons
195Pt 33.832% 195Pt is stable wi 117 neutrons
196Pt 25.242% 196Pt is stable wi 118 neutrons
198Pt 7.163% >3.2×1014 y α 0.0870 194Os
ββ 1.0472 198Hg
· r

Platinum is a chemical element wi the chemical seembol Pt an an atomic nummer o 78.

Its name is derived frae the Spainyie term platina, which is leeterally translatit intae "little siller".[1][2] It is a dense, malleable, ductile, precious, gray-white transeetion metal.

Platinum haes sax naiturally occurring isotopes. It is ane o the rarest elements in the Yird's crust an haes an average abundance o approximately 5 μg/kg. It is the least reactive metal. It occurs in some nickel an copper ores alang wi some native deposits, maistly in Sooth Africae, which accoonts for 80% o the warld production.

As a member o the platinum group o elements, as well as o the group 10 o the periodic table o elements, platinum is generally non-reactive. It exhibits a remarkable resistance tae corrosion, even at heich temperaturs, an as such is considered a noble metal. As a result, platinum is eften foond chemically uncombined as native platinum. Acause it occurs naiturally in the alluvial sands o various rivers, it wis first uised bi pre-Columbie Sooth American natives tae produce artifacts. It wis referenced in European writings as early as 16t century, but it wis nae till Antonio de Ulloa published a report on a new metal o Colombie origin in 1748 that it acame investigated bi scientists.

Platinum is uised in catalytic converters, laboratory equipment, electrical contacts an electrodes, platinum resistance thermometers, dentistry equipment, an jewelry. Acause anly a few hundred tonnes are produced annually, it is a scarce material, an is heichly valuable an is a major precious metal commodity. Bein a hivy metal, it leads tae health issues upon exposur tae its salts, but due tae its corrosion resistance, it is nae as toxic as some metals.[3] Compoonds containin platinum, maist notably cisplatin, are applied in chemotherapy against certain types o cancer.[4]

References[eedit | eedit soorce]

  1. "platinum (Pt)." Encyclopædia Britannica Online. Encyclopædia Britannica Inc., 2012. Web. 24 April 2012
  2. Harper, Douglas. "platinum". Online Etymology Dictionary. 
  3. "Platinum|". 
  4. Wheate, NJ; Walker, S; Craig, GE; Oun, R (2010). "The status of platinum anticancer drugs in the clinic and in clinical trials". Dalton transactions (Cambridge, England : 2003) 39 (35): 8113–27. doi:10.1039/C0DT00292E. PMID 20593091. 

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