Tennant discovered iridium in 1803 in residuals remaining when raw platinum was dissolved with aqua regia. The naming of iridium is very feasible because the salts are brightly colored.
Iridium, including platinum group families. It is white (same as platinum) but with a bit of pseudo-yellow. Because iridium is very hard and brittle, it is very difficult to use or to be shaped. (Read Common Uses of Platinum in Everyday Life)
The iridium element occurs as a natural alloy of Platinum and Osmium. Iridium is the most corrosion-resistant metal, and was used in the manufacture of standard lengths in meters in Paris, which is a mixture of 90% platinum and 10% iridium. This standard was eventually replaced in 1960 with krypton.
Iridium is not present in nature along with platinum and platinum group metals in soil minerals.
Description of the Iridium Element, as follows :
- Symbols: Ir
- Atomic Radius: 1.36 Å
- Atom Volume: 8.54 cm3 / mol
- Atomic Mass: 192.22
- Boiling Point: 4700 K
- Covalence Radius: 1.27 Å
- Crystal Structure: fcc
- Mass Type: 22.6 g / cm3
- Electrical Conductivity: 21.3 x 106 ohm-1cm-1
- Electronegativity: 2.2
- Electron Configuration: [Xe] 4f14 5d7 6s2
- Entalpi Formation: 26.36 kJ / mol
- Heat Conductivity: 147 Wm-1K-1
- Potential Ionization: 9.1 V
- Melting Point: 2720 K
- Oxidation Numbers: 2,3,4,6
- Heat Capacity: 0.13 Jg-1K-1
- Evaporation enthalpy: 563.58 kJ / mol
- Solid phase
- Liquid mass at melting point 19 g / cm³
- Boiling point 4701 K (4428 ° C, 8002 ° F)
- Heating heat 41.12 kJ / mol
- Heat of evaporation 231.8 kJ / mol
- Heat Capacity (25 ° C) 25.10 J / (mol · K)
1. cubic face centered crystal structure
2. Oxidation number 2, 3, 4, 6 (mildly basic oxide)
3. Electronegativity 2.20 (Pauling scale)
4. Energy ionization
First 880 kJ / mol
Second 1600 kJ / mol
5. Atoms radius 135 pm
6. Atoms radius (calculated) 180 pm
7. The covalent radius 137 pm
1. Electrical resistivity (20 ° C) 47.1 nΩ · m
2. Thermal Conductivity (300 K) 147 W / (m · K)
3. Thermal expansion (25 ° C) 6.4 μm / (m · K)
4. Sound speed (thin wire) (20 ° C) 4825 m / s
5. Young Modulus 528 GPa
6. Slide Modulus 210 GPa
7. 320 GPa jointed modulus
8. Poisson’s ratio 0.26
9. Mohs 6.5 hardness scale
10. Vickers Violence 1760 MPa
11. Brinell Hardness 1670 MPa
12. CAS number 7439-88-5
Iridium is insoluble in acids and even aqua regia, but soluble in aqueous salts such as NaCl, and NaCN. The weights of the iridium species approximate the weight of the osmium species. Calculation of iridium and osmium density of the space layers gave the values of 22.65 and 22.61 g / cm3. This value is more reliable than a physical measurement to determine which element is heavier. (Read also Transformation of a Gas into a Solid Solution)
Levels of iridium in soil plants below 20 ppb. Iridium is found as a free element, and also as an osmiridium and idrosmine alloy iridium-osmium. Most of the iridium comes from South Africa. Annual world production of about 3 tons. Reserves not yet estimated.
Uses of Iridium in Everyday Life
Here are the use of uses of Iridium in everyday life:
1. As a hardening agent for platinum
A small amount of iridium is usually added to make Platinum tougher, creating a powerful alloy that retains the advantage of pure platinum.
2.Iridium is used to make cups and equipment that require high temperatures
In 1908, Sir William Crookes designed the first iridium crucibles produced by Johnson Matthey, and found that they have great advantages over pure platinum vessels in making cups. (Read also Characteristics and Uses of Nitrogen in Daily Life)
- Iridium is also used as an electrical contact material
This element forms an alloy with osmium used for the pen point and the bearing of compass. (Read Interesting Characteristic and Uses of Rhodium)
In 1884, an ink-pocket pen appeared with the working principle of a capillary pipe, one of which was made by an American, Lewis Edson Waterman. Waterman’s pen has indeed made its own revolution in the field of writing.
Because humans no longer need to dip the pen again and again in the ink after writing a few words. Waterman has been wearing a gold-draped iridium plate on the pen point.
- Standard meter bars
Standard meter bars have a composition of 90% platinum, 10% iridium
- Spark plugs
Spark plugs are divided into several types, one of which is iridium. This type of spark plug has many advantages, but the price is more expensive.
Iridium spark plugs is care-free spark plugs. Surely it makes the iridium model better than the conventional spark plugs. The iridium spark plug is highly heat resistant, but it has a smaller electrode material than the standard spark plugs.
Iridium spark plugs is more expensive, but it has more benefits, one of them is maintenance free because it is designed using carbon fouling technology, it can automatically clean carbon burning on the electrode, so it does not need to be cleaned manually. (Read Uses of Carbon Compound Related to Their Properties)
In addition the iridium spark plug is a very hard and anti-corrosion and heat-resistant metal element. In addition, type of iridium spark plugs have material electrode material that has a high boiling point that is 2500 degrees Celsius range. With such power, iridium spark plugs are widely selected by the manufacturer. In addition, the burning of 1 point becomes more focused and is believed to be able to serve racing engines that require a higher spark.
Iridium spark plugs requires a lower voltage to trigger burning so when the starter is done, it rarely fails.
Iridium is the material with the highest melting point compared to other materials, even gold though.
The higher the melting point of an electrode material, the better the ignition concentration the electrode can produce. (Read Chemicals Used in Electric Car Batteries)
The Boiling point of each spark plug material as follows :
- iridium = 2500° C
- platinum = 2000° C
- nickel = 1500° C
- gold = 1200° C
- silver = 800° C
- To coat electrodes in chlor-alkali processes, and catalysts
Currently iridium demand comes primarily from the electronics industry, the automotive industry and from the chemical industry, where it is used to coat electrodes in chlor-alkali processes, and catalysts. (Read Hydrogen Peroxide Applications)
- The iridium radioactive isotope is used in radiation therapy for cancer treatment
- Abundance and Isotopes
- Abundance of crust: 0.4 parts per billion weight, 0.05 parts per billion mol
- Abundance of the solar system: 2 parts per billion weight, 0.01 parts per billion moles
- Cost, pure: $ 4200 per 100g
- Cost, bulk: $ 2300 per 100g
- Commercially, iridium is being recovered as a by-product of the nickel mining industry
Meanwhile, that’s all the uses of Iridium in everyday life.
The health effects of iridium
Potential health effects: Eye: may cause eye irritation. Skin: low hazard for handling of ordinary industry. Ingestion: may cause irritation of the digestive tract. Expected to be a low consumption hazard. Inhalation: low hazards for handling of regular industry. (Read Common Nickel Uses in Daily Life)
Environmental impact of iridium
Do not let the product reach groundwater, water bodies or sewerage systems. To sum up, there are many uses of Iridium in everyday life, just be wise to use any chemicals compound.