Element Osmium
Osmium (from Greek ὀσμή osme, “smell”) is a chemical element with the symbol Os and atomic number 76.
It is a hard, brittle, bluish-white transition metal in the platinum group that is found as a trace element in alloys, mostly in platinum ores.
Osmium has a blue-gray tint and is the densest stable element; it is approximately twice as dense as lead[3] and slightly denser than iridium. Calculations of density from the X-ray diffraction data may produce the most reliable data for these elements, giving a value of 22.587±0.009 g/cm3 for osmium, slightly denser than the 22.562±0.009 g/cm3 of iridium; both metals are nearly 23 times as dense as water
Names and Identifiers
Chemical Formula: | Os |
CAS: | 7440-04-2 |
Molecular Weight: | 190.230 g/mol |
EC Number : | 231-114-0 |
MDL Number: | MFCD00011147 |
Color: | bluish gray/ bluish-white |
Other Names: | Osmio |
PubChem CID: | 22379 |
IUPAC Name: | Osmium |
Inchl: | InChI=1S/Os |
InChI Key: | SYQBFIAQOQZEGI-UHFFFAOYSA-N |
Canonical SMILES: | [Os] |
ICSC Number: | n/a |
Physical & Chemical Properties
Phase: | Solid |
Density: | 22.59 g/cm³ |
Boiling Point: | 5285 K (5012 °C, 9054 °F) |
Melting Point: | 3306 K (3033 °C, 5491 °F) |
Molecular Formula: | Os |
Flash Point: | n/a |
Exact Mass: | 191.961502 |
Symbol: | |
Signal Word: | Danger |
Hazard Statements: | H228-H315-H318-H335 |
Precautionary Statements: | P210-P261-P280-P305 + P351 + P338 |
Hazard Codes: | F,Xi |
Risk Phrases: | 11-37/38-41-36/38 |
Safety Phrases: | S16-S26-S36/37/39 |
RIDADR: | UN 3089 4.1/PG 2 |
WGK Germany: | n/a |
RTECS: | RN1100000 |
Packaging Group: | II |
Hazard Class: | 4.1 |
Osmium has seven naturally occurring isotopes, six of which are stable: 184Os, 187Os, 188Os, 189Os, 190Os, and (most abundant) 192Os. 186 Os undergoes alpha decay with such a long half-life (2.0±1.1)×1015 years, approximately 140000 times the age of the universe, that for practical purposes it can be considered stable.
Naturally occurring isotopes
Isotope | Mass/Da | Natural abundance (atom %) | Nuclear spin (I) | Magnetic moment (μ/μN) |
---|---|---|---|---|
184Os | 183.952488 (4) | 0.02 (1) | 0 | |
186Os | 185.953830 (4) | 1.59 (3) | 0 | |
187Os | 186.955741 (3) | 1.96 (2) | 1/2 | 0.06465185 |
188Os | 187.955830 (3) | 13.24 (8) | 0 | |
189Os | 188.958137 (4) | 16.15 (5) | 3/2 | 0.659933 |
190Os | 189.958436 (4) | 26.26 (2) | 0 | |
192Os | 191.961467 (4) | 40.78 (19) | 0 |
Radiosotope data
Isotope | Mass/Da | Half-life | Mode of decay | Nuclear spin | Nuclear magnetic moment |
---|---|---|---|---|---|
182Os | 181.95219 | 21.5 h | EC to 182Re | 0 | |
183Os | 182.9531 | 13 h | EC to 183Re | 9/2 | |
185Os | 184.954043 | 93.6 d | EC to 185Re | 1/2 | |
191Os | 190.960928 | 15.4 d | β– to 191Ir | 9/2 | |
193Os | 192.964138 | 30.5 h | β– to 193Ir | 3/2 | 0.73 |
194Os | 193.965179 | 6.0 y | β– to 194Ir | 0 |