Friday, December 1, 2006

Osmium






Nextel ringtones Rhenium - '''Osmium''' - Abbey Diaz Iridium

Free ringtones Ruthenium/Ru
'''Os'''Majo Mills Hassium/Hs  
Mosquito ringtone Image:Os-TableImage.png
Sabrina Martins Periodic table (standard)/Full table



'''General'''

Nextel ringtones List of elements by name/Name, Abbey Diaz List of elements by symbol/Symbol, Free ringtones List of elements by number/NumberOsmium, Os, 76

Majo Mills Chemical series Cingular Ringtones transition metals

landed hard periodic table group/Group, economic modernisation periodic table period/Period, advance across periodic table block/Blockinitial lukewarm group 8 element/8 (VIIIB), became self period 6 element/6, tactic was d-block/d

women latinos Density, endings of Mohs hardness scale/Hardness 22610 kilman sarah kilogram per cubic metre/kg/m3, 7

nutter wants color/Appearance Silvery, Blue Castthey lease Image:Os,76.jpg/125px/

'''Atomic properties'''

alarmingly apparently Atomic weight 190.23 at baptism Atomic mass unit/amu

bases rivera Atomic radius (calc.) 130 (185) from troubled picometre/pm

record yards Covalent radius 128 pm

for ferraris van der Waals radius no data

always learn Electron configuration traurig which [xenon/Xe]4month bills f-orbital/f145d66s-orbital/s2

electron/e- 's per energy level2, 8, 18, 32, 14, 2

Oxidation states (Oxide) ±0.7 (mildly acidic)

Crystal structure hexagonal

'''Physical properties'''
State of matter Solid (magnetism/__)

Melting point 3306 Kelvin/K (5491 °Fahrenheit/F)

Boiling point 5285 K (9054 °F)

Molar volume 8.42 scientific notation/×10-6 cubic metre per mole/m3/mol

Heat of vaporization 627.6 kilojoule per mole/kJ/mol

Heat of fusion 31.8 kJ/mol

Vapor pressure 2.52 Pascal/Pa at 3300 K

Speed of sound 4940 metre per second/m/s at 293.15 K

'''Miscellaneous'''

Electronegativity 2.2 (Pauling scale)

Specific heat capacity 130 joule per kilogram-kelvin/J/(kg*K)

Electrical conductivity 10.9 106/m ohm

Thermal conductivity 87.6 watt per metre-kelvin/W/(m*K)

1st ionization potential 840 kJ/mol

2nd ionization potential 1600 kJ/mol

'''Most stable isotopes'''




Isotope/isonatural abundance/NAhalf-life decay mode/DMdecay energy/DE mega/Melectron volt/eVdecay product/DP

184Os0.02%>5.6 E13 year/y    

186Os1.58%>2.0 E15 y alpha decay/α2.822tungsten/182W

187Os1.6%Os is stable isotope/stable with 111 neutrons

188Os13.3%Os is stable with 112 neutrons

189Os16.1%Os is stable with 113 neutrons

190Os24.6%Os is stable with 114 neutrons

192Os'''41.0%'''Os is stable with 116 neutrons

194Os6 y beta emission/β-0.097iridium/194Ir



SI units & standard temperature and pressure/STP are used except where noted.


'''Osmium''' is a chemical element in the periodic table that has the symbol '''Os''' and atomic number 76. A hard brittle blue-gray or blue-black transition metal in the platinum family, osmium is the densest natural element and is used in some alloys with platinum and iridium. Osmium is found native as an alloy in platinum ore and its tetroxide has been used to stain tissues and in fingerprinting. Alloys of osmium are employed in fountain pen tips, electrical contacts and in other applications where extreme durability and hardness are needed.

Notable characteristics
Osmium in a metal/metallic form is extremely density/dense, blue white, brittle and lustrous even at high temperatures, but proves to be extremely difficult to make. Powdered osmium is easier to make, but powdered osmium exposed to air leads to the formation of osmium tetroxide (Osoxygen/O4), which is toxic. The oxide is also a powerful oxidation/oxidizing agent, emits a strong smell and boils at 130°Celsius/C.

Due to its very high density osmium is generally considered to be the heaviest known element narrowly defeating iridium. However, calculations of density from the space lattice may produce more reliable data for these elements than actual measurements and give a density of 22650 kilogram per cubic metre/kg/m3 for iridium versus 22661 kg/m3 for osmium. Definitive selection between the two is therefore not possible at this time. It's just too close to call. If one distinguishes different isotopes, then the heaviest ordinary substance would be Osmium-192.

This metal has the highest melting point and the lowest vapor pressure of the platinum family. Common oxidation states of osmium are +4 and +3, but oxidation states from +1 to +8 are observed.

Applications
Because of the extreme toxicity of its oxide, osmium is rarely used in its pure state, and is instead often alloyed with other metals that are used in high wear applications. Osmium alloys are very hard and along with other platinum group metals is almost entirely used in alloys employed in the tips of fountain pens, phonograph needles, instrument pivots, and electrical contacts.

Osmium tetroxide has been used in fingerprint detection and in staining fatty tissue for microscope slides. An alloy of 90% platinum and 10% osmium (90/10) is used in surgical implants such as artificial pacemaker/pacemakers and replacement pulmonary valves.

The tetroxide (and a related compound, potassium osmate) are important oxidants for chemical synthesis.

History
Osmium (Greek language/Greek ''osme'' meaning "a smell") was discovered in 1803 by Smithson Tennant in London, England along with iridium in the residue of dissolving platinum in aqua regia.

Occurrence
This transition metal is found in iridiosmium a naturally occurring alloy of iridium and osmium and in platinum-bearing river sands in the Ural Mountains, and North America/North and South America. It is also occurs in nickel-bearing ores found in the Sudbury, Ontario region with other platinum group metals. Even though the quantity of platinum metals found in these ores is small, the large volume of nickel ores processed makes commercial recovery possible.

Compounds
Osmium tetroxide OsO4

Isotopes
Osmium has seven naturally-occurring isotopes, 5 of which are stable: Os-187, Os-188, Os-189, Os-190, and (most abundant) Os-192. Os-184, Os-186 have absurdly long half lifes and for practical purposes can be considered to be stable as well. Os-187 is the daughter of rhenium-187 (half-life 4.56 x 1010 years) and is most often measured in a Os-187/Os-186 ratio. This ratio, as well as the rhenium/Re-187/Os-187 ratio, have been used extensively in dating terrestrial as well as meteorite/meteoric Rock (geology)/rocks. However, the most notable application of Os in dating has been in conjunction with iridium (element)/iridium, to analyze the layer of shocked quartz along the K-T boundary that marks the extinction of the dinosaurs 65 million years ago.

Precautions
Osmium tetroxide is highly toxic. Airborne concentrations of osmium as low as 10-7 gram/g/cubic metre/m³ can cause lung congestion, skin or eye damage.

References
*http://periodic.lanl.gov/elements/76.html

External links
*http://www.webelements.com/webelements/elements/text/Os/index.html
*http://environmentalchemistry.com/yogi/periodic/Os.html

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Tag: Chemical elements
Tag: Transition metals

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