Iridium
IRIDIUM BLACK · IRIDIUM POWDER · Iridium C · IRIDIUM ON ALUMINA · IRIDIUM ICP STANDARD · Iridium powder, -22 mesh, Premion(R), 99.99% (metals basis) · IRIDIUM · IR000210
Identifiers & Physical Properties
| CAS No. | 22542-08-1 |
|---|---|
| Molecular formula | Ir |
| Average molar mass | 192.22 g/mol |
| Monoisotopic mass | 192.9629264 g/mol |
| SMILES | [Ir] |
| InChIKey | GKOZUEZYRPOHIO-UHFFFAOYSA-N |
| PubChem CID | 23924 |
| ChEBI | CHEBI:49666 |
| EC No. | 231-095-9 |
| DTXSID | DTXSID0064674 |
Chemical & Physical Properties
| Topological polar surface area | 0 |
|---|---|
| Hydrogen bond donors | 0 |
| Hydrogen bond acceptors | 0 |
| Rotatable bonds | 0 |
| Heavy atoms | 1 |
| Formal charge | 0 |
| Complexity | 0 |
| Chemical classes | Metals -> Elements, Metallic |
| SpringerMaterials Properties | electron density of states |
| Density | 22.42 at 17 °C21.56 @25 °C22.65 g/cm3 (lit.) |
| Color/Form | Silver-white, face-centered cubic lattice |
| Corrosivity | Not attacked by any acid or by aqua regia. |
| Boiling point | 4,428 °C4428 °C @760 [mm Hg]4130 °C (lit.) |
| Melting point | 2,446 °C2450 °C (lit.) |
| Vapor pressure | 0.467 Pa at melting point |
| Physical Description | Silver-white metal[Hawley] |
| Other Experimental Properties | Powdered iridium metal can ignite in air.Enthalpy of fusion 41.12 kJ/molSpecific heat 0.0307 cal/g/deg CMohs' hardness 6.5Best solvent: concentrated hydrochloric acid and sodium perchlorate at 125 to 150 °CFor more Other Experimental Properties (Complete) data for IRIDIUM, ELEMENTAL (6 total), please visit the HSDB record page. |
| Storage conditions | Flammables area |
| Solubility | Soluble in aqua regia.INSOLUBLE |
| Physical state | wire |
| Color | White to pale yellow |
| Specific gravity | 22.421 |
| Resistivity | 4.71 μΩ-cm |
| Electrical Conductivity | 2.1× 107S/m |
| Thermal conductivity | 150 W/(m·K) |
| Specific heat capacity | Cp(crystal): 0.13 J/(g·K)Cp(gas): 0.11 J/(g·K), at 25℃ |
| Merck | 13,5102 |
| InChI | 1S/Ir |
| InChIKey | GKOZUEZYRPOHIO-UHFFFAOYSA-N |
| SMILES | [Ir] |
| Hardness, Brinell | 352, Converted from Vickers for 3000 kg load/10 mm ball Brinell test. |
| Hardness, Rockwell A | 69, Converted from Vickers. |
| Hardness, Rockwell C | 37, Converted from Vickers. |
| Hardness, Vickers | 370 |
| Modulus of Elasticity | 524 GPa |
| Poissons Ratio | 0.26 |
| Shear Modulus | 208 GPa, Calculated |
| CAS DataBase Reference | 7439-88-5(CAS DataBase Reference) |
| FDA UNII | 44448S9773 |
| NIST Chemistry Reference | Iridium(7439-88-5) |
| EPA Substance Registry System | Iridium (7439-88-5) |
| UNSPSC Code | 41116107 |
| NACRES | NA.24 |
| GHS pictogram | GHS02 |
| Signal word | Danger |
| GHS hazard statements | H228 |
| GHS precautionary statements | P210-P240-P241-P280-P370+P378 |
| Hazard symbols | F,Xi |
| Risk statements (R) | 36-36/37/38-11 |
| Safety statements (S) | 16-26-36/37/39 |
| UN transport number | UN 3089 4.1/PG 2 |
| Water hazard class (WGK) | 3 |
| TSCA inventory status | TSCA listed |
| Hazard class | 4.1 |
| Packing group | III |
| Customs code | 28439000 |
| Hazardous substances data | 7439-88-5(Hazardous Substances Data) |
| REACH registrations | Active |
| Limited quantities | 1.0 Kg (2.2 lbs) |
| Excepted quantities | Max Inner Pack (30g or 30ml) and Max Outer Pack (500g or 500ml) |
Safety & Regulations
| GHS classification | This chemical does not meet GHS hazard criteria for 36.9% (92 of 249) of reports.DangerH228 (18.1%): Flammable solid [Danger Flammable solids]P210, P240, P241, P264+P265, P273, P280, P305+P351+P338, P337+P317, P370+P378, and P501 (click each P-code to see the statement)Aggregated GHS information provided per 249 reports by companies from 9 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies. |
|---|---|
| Regulatory information | Chemical: IridiumStatus: Active Update: 17-03-2021 https://echa.europa.eu/registration-dossier/-/registered-dossier/17763Iridium, powder: Does not have an individual approval but may be used under an appropriate group standard |
| Other safety information | IMAP assessments - Iridium: Human health tier I assessment |
| Fire potential | The finely divided catalytic metal may be pyrophoric. |
| Hazards summary | Iridium salts can cause immunologic, occupational contact urticaria[Kanerva, p. 219] The metals in this group [platinum, palladium, iridium, osmium, rhodium, and ruthenium] generally are nontoxic in the metallic state, but the soluble halide salts (particularly of Pt) and osmium tetroxide are highly reactive. Exposure to these elements results in hypersensitivity allergic reactions in susceptible individuals. [Sullivan, p. 911] See Iridium-192. |
| Hazard Classes and Categories | Flam. Sol. 1 (18.1%) |
| Hazardous Reactivities and Incompatibilities | A catalytic metal. The powdered metal may ignite spontaneously in air. Violent reaction or ignition on contact with interhalogens (e.g., bromine pentafluoridechlorine trifluoride). |
| Disposal methods | SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air qualitypotential migration in soil or watereffects on animal, aquatic, and plant lifeand conformance with environmental and public health regulations |
| Protective Action Criteria (PAC) | 12 [mg/m3]130 [mg/m3]790 [mg/m3] |
| Antidote and Emergency Treatment | Basic treatment: Establish a patent airway. Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if needed. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with normal saline during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 mL/kg up to 200 mL of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . Cover skin burns with dry sterile dressings after decontamination ... . /Poison A and B/Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in respiratory arrest. Positive pressure ventilation techniques with a bag valve mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start an IV with D5W TKO /"To keep open", minimal flow rate/. Use lactated Ringer's if signs of hypovolemia are present. Watch for signs of fluid overload. For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of fluid overload ... . Treat seizures with diazepam (Valium) ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Poison A and B/ |
| Water hazard class (WGK) | 3 |
| TSCA inventory status | TSCA listed |
| UN transport number | UN 3089 4.1/PG 2 |
| Customs code | 28439000 |
| Risk statements (R) | 36-36/37/38-11 |
| Signal word | Danger |
| GHS pictogram | GHS02 |
| Hazard symbols | F,Xi |
| Safety statements (S) | 16-26-36/37/39 |
| Hazard class | 4.1 |
| Packing group | III |
| GHS hazard statements | H228 |
| Limited quantities | 1.0 Kg (2.2 lbs) |
| Excepted quantities | Max Inner Pack (30g or 30ml) and Max Outer Pack (500g or 500ml) |
| REACH registrations | Active |
| GHS precautionary statements | P210-P240-P241-P280-P370+P378 |
| Hazardous substances data | 7439-88-5(Hazardous Substances Data) |
Applications & Uses
Description
Iridium metal was detected in the black residue of aqua regia extract of platinum and identified as an element by British chemist Smithson Tennant in 1803. Around the same time, existence of this new metal was proposed by Vauquelin and deFourcroy in France in the course of their extraction of platinum by aqua regia. Tennant named this element Iridium after the Greek word, Iris, meaning rainbow. Iridium occurs in small amounts in native platinum or platinum metal alloys. Iridium and osmium together constitute “osmiridium,” which is resistant to chemical attack and is a byproduct of platinum extraction.
Uses
The most important use of iridium is as an alloying metal for platinum and palladium. Such alloys are used for jewelry, decorative purposes, electrical contacts, thermocouples, crucibles, electrodes, hypodermic needles, and medical accessories. Iridium enhances resistance of platinum to chemical attack and corrosion. It also enhances hardness and tensile strength. The radioisotope Ir-192 is used in examination of ferrous welds and in other radiographic applications.
Occurrence
Iridium is the 83rd most abundant element and is found mixed with platinum, osmium,and nickel ores. The minerals containing iridium are found in Russia, South Africa, Canada,and Alaska.Iridium metal is separated from its other metal ores when the combined minerals aredissolved with a strong acid know as aqua regia, which is a mixture of 25% nitric acid and75% hydrochloric acid. Aqua regia is the only acid that will dissolve platinum and gold.Once the platinum and other metals are dissolved, the iridium, which is insoluble in thisstrong acid, becomes the residue. The refined iridium ends up in the form of either powderor crystals.An interesting story as to how most of the iridium appeared on Earth was explainedrecently by scientists who discovered a thin layer of iridium in the sediments that were laiddown in the Earth’s crust at the end of the Cretaceous period. This was a period about 65 millionyears ago when meteors and asteroids crashed into the Earth. These extraterrestrial bodiescontained a high percentage of iridium. Dust from the impact spread around the Earth andblocked the sun for months, resulting in the extinction of many plants and animals, includingthe dinosaurs. This extensive dust cloud also deposited a thin coat of the element iridium thatwas contained in the fiery bolides.
History
Discovered in 1803 by Tennant in the residue left when crude platinum is dissolved by aqua regia. The name iridium is appropriate, for its salts are highly colored. Iridium, a metal of the platinum family, is white, similar to platinum, but with a slight yellowish cast. It is very hard and brittle, making it very hard to machine, form, or work. It is the most corrosion-resistant metal known, and was used in making the standard meterbar of Paris, which is a 90% platinum–10% iridium alloy. This meter bar was replaced in 1960 as a fundamental unit of length (see under Krypton). Iridium is not attacked by any of the acids nor by aqua regia, but is attacked by molten salts, such as NaCl and NaCN. Iridium occurs uncombined in nature with platinum and other metals of this family in alluvial deposits. It is recovered as a by-product from the nickel mining industry. The largest reserves and production of the platinum group of metals, which includes iridium, is in South Africa, followed by Russia and Canada. The U.S. has only one active mine, located at Nye, MT. The presence of iridium has recently been used in examining the Cretaceous-Tertiary (K-T) boundary. Meteorites contain small amounts of iridium. Because iridium is found widely distributed at the K-T boundary, it has been suggested that a large meteorite or asteroid collided with the Earth, killing the dinosaurs, and creating a large dust cloud and crater. Searches for such a crater point to one in the Yucatan, known as Chicxulub. Iridium has found use in making crucibles and apparatus for use at high temperatures. It is also used for electrical contacts. Its principal use is as a hardening agent for platinum. With osmium, it forms an alloy that is used for tipping pens and compass bearings. The specific gravity of iridium is only very slightly lower than that of osmium, which has been generally credited as being the heaviest known element. Calculations of the densities of iridium and osmium from the space lattices give values of 22.65 and 22.61 g/cm3, respectively. These values may be more reliable than actual physical measurements. At present, therefore, we know that either iridium or osmium is the densest known element, but the data do not yet allow selection between the two. Natural iridium contains two stable isotopes. Forty-five other isotopes, all radioactive, are now recognized. Iridium (99.9%) costs about $100/g.
Uses
Iridium’s most common use is as an alloy metal that, when added to platinum, makes itharder and more durable. It is also mixed with other metals to make electrical contacts, thermocouples(two dissimilar metals joined to form a special type of thermometer), and instrumentsthat will withstand high temperatures without breaking down. It is also used to makespecial laboratory vessels because iridium will not react with most chemical substances. Analloy of iridium and platinum is used as the standard kilogram weight because it is noncorrosiveand will not oxidize and, thus, change its weight over long periods of time.The radioisotope, iridium-192, is used to treat cancer and to take X-ray pictures of metalcastings to detect flaws. Iridium is also used as a catalyst for several chemical reactions.
Uses
In manufacturing crucibles; in hardening platinum; in making nibs for fountain-pen points.
Uses
The primary use of iridium is as a hardening agent in platinum alloys. Other uses are for the making of crucibles and devices that require high temperatures. Osmium/iridium alloys are used for compass bearings. Iridium is commonly used in complexes like Ir(mppy)3 and other complexes in polymer LED technology to increase the efficiency from 25% to about 100% due to triplet harvesting. Used in high-dose radiation therapy for the treatment of prostate and other forms of cancer. Iridium is used in tips of ballpoint pens. Iridium is used as a catalyst for carbonylation of methanol to create acetic acid. At one time, iridium as an alloy with platinum, was used in bushing the vents of heavy ordnance and, in a finely powdered condition (iridium black) for painting porcelain black.