Osmium

Osmium (British: osmium) is an element of atomic number 76. The symbol of an element is Os. One of the platinoid elements (a noble metal).

Rhenium ← Osmium → Iridium Ru ↑ Os ↓ Hs 76Os Periodic table
Appearance
Bluish silver-white
General characteristic
Name, Sign, Number	Osmium, Os, 76
Classification	Transition metal
Family, Period, Block	8, 6, d
Atomic weight	190.23
Electron configuration	[Xe] 4f14 5d6 6s2
Electron shell	2, 8, 18, 32, 14, 2（Image）
Physical characteristic
Aspect	Solid
Density (room temperature neighborhood)	22.59 [1] g/cm3
Liquid density at the melting point	20 g/cm3
Melting point	3306 K, 3,033 degrees Celsius, 5,491 degrees Fahrenheit
The boiling point	5285 K, 5,012 degrees Celsius, 9,054 degrees Fahrenheit
Heat of fusion	57.85 kJ/mol
The heat of evaporation	738 kJ/mol
Thermal capacity	(25 degrees Celsius) 24.7 J/(mol·K)
Vapor pressure
Pressure (Pa) 1 10 100 1 k 10 k 100 k Temperature (K) 3160 3423 3751 4148 4638 5256
Atom properties
Oxidation state	8, 7, 6, 5, 4, 3, 2, 1, 0, -1, -2 (acidulous oxide)
Electronegativity	2.2 (value of the polling)
Ionization energy	The first： 840 kJ/mol
	The second： 1600 kJ/mol
Zirconium	135 pm
Covalent radius	144+-4 pm
Others
Crystal structure	Hexagonal system
Magnetism	Paramagnetic [2]
Electric specific resistance	(0 degrees Celsius) 81.2 nΩ·m
Thermal conductivity	(300 K) 87.6 W/(m·K)
Thermal expansion rate	(25 degrees Celsius) 5.1µm/(m·K)
The speed to come of the sound (minute rod)	(20 degrees Celsius) 4,940m/s
Rigidity	222 GPa
Volume coefficient of elasticity	462 GPa
Poisson ratio	0.25
Mohs scale	7.0
The yellowtail flannel hardness	3920 MPa
CAS registration number	7440-04-2
The most stable isotope
The details refer to an isotope of osmium
Isotope NA Half-life DM DE (MeV) DP 184Os 0.02% > 5.6*1,013 y (unconfirmed) ε ε 1.452 184W 185Os syn 93.6 d ε 1.013 185Re 186Os 1.59% 2.0*1,015 y α 2.822 182W 187Os 1.96% It is stable in 111 neutrons 188Os 13.24% It is stable in 112 neutrons 189Os 16.15% It is stable in 113 neutrons 190Os 26.26% It is stable in 114 neutrons 191Os syn 15.4 d β - 0.314 191Ir 192Os 40.78% > 9.8*1,012 y (unconfirmed) β-β - 0.414 192Pt 193Os syn 30.11 d β - 1.141 193Ir 194Os syn 6 y β - 0.097 194Ir
Indication

Table of contents

Summary

The metal (transition metal) specific gravity of the blue gray 22.57, the melting point 3,045 degrees Celsius (there is the experimental value of 2,700 degrees Celsius, too). The boiling point exceeds 5,000 degrees Celsius. The crystal structure that is stable by normal temperature, ordinary pressure is hexagonal close-packed structure structure (HCP). The specific gravity is the biggest among all elements (as for iridium the second).

I can take the oxidation state to +1-+8 value (+4 value becomes stable most). It is easy to be oxidized most in platinum group. I react at a high temperature with halogen, but do not dissolve in aqua regia very much. It is a rare metal (rare metal).

When I leave you unattended in the air or the powder heats up, I produce oxidation osmium (VIII) of the deadly poison easily.

It is the element which is the highest in density [¹].

History

In 1803, I was discovered in an aqua regia dissolution residual substance of rough platinum with iridium by a British tenant (Smithson Tennant, 1761-1815). Because the osmic acid which occurred when I heated up gave off a special smell, I was named for ο σ μ η (osmè, smell) of the Greek.

Use as the material

It is corrosion-resistant firmly, and the alloy with platinum and iridium is superior, and the alloy with iridium to produce particularly naturally is called osmiridium and iridosmine which content is high. I am used for the pen point of the fountain pen and produce a lot it in Hokkaido in Japan. In addition, I use a property that oxidation osmium and organic matter perform a reaction (reduction) and produce an osmium simple substance (black) and may be used for the fingerprint detection.

Compound of osmium

• Oxidation osmium (IV) (OsO₂)
• Oxidation osmium (VIII) (OsO₄) - I am catalyzed, but am toxic

Isotope

The details refer to "an isotope of osmium"

Gallery

•  

  The artificial crystal which a characteristic crackle three twin crystal can observe

•  

  Artificial crystal

Source

1. In ^ ^{a b} Theodore gray "element illustrated book Mari Takei reason which is the most beautiful in the world", wound former company, 2010, it is 177 pages
2. ^ Magnetic susceptibility of the elements and inorganic compounds, in Handbook of Chemistry and Physics 81st edition, CRC press.

Outside link

Wiki media Commons has the media in conjunction with osmium.

• Osmium Niihama National College of Technology

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