Iridium

77

Ir

192.217(3)
  • Name: Iridium
  • Symbol: Ir
  • Atomic number: 77
  • Atomic weight: 192.217(3)
  • CAS Registry ID: 7439-88-5
  • Group name: Precious metal
  • Period number: 6
  • Block: d-block
  • Switch:
  • Compare Element

Description

Iridium is a transition metal that is a bright silver white color in its natural solid state. It can be attached by molten salts, but it has the strongest anti-corrosive properties of all the metal elements. Iridium has an atomic weight of 192.217, a melting point of 4471 °F, and a boiling point of 8002 °F. Some common uses of iridium include: as a component in platinum alloys as a hardening agent, as a component in crucibles that must withstand high temperatures, as a component in spark plugs, and in radiation therapy.

enlarge image

Isolation

Iridium occurs in nature in alluvial deposits with other platinum group metals. It may also be obtained as a by-product of nickel processing.

enlarge image

The isolation of iridium from its natural sources is extremely complicated and complex; the difficulties of iridium isolation make small scale laboratory isolation procedures for this element nearly impossible. The beginning isolation process involves treating the mineral containing iridium to remove any silver, gold, platinum, or palladium that are also present in the mineral. This step is carried out by treating the mineral with sodium bisulphate and melting the products. Next, the solution is extracted with water; this solution contains an insoluble residue of iridium. The residue is melted using sodium peroxide and then extracted again into water to remove any ruthenium and osmium salts that remain. Iridium oxide is left and it is dissolved using a mixture of hydrochloric acid and nitric acid. The result of this step yields a compound of iridium that contains chlorine and ammonium. Evaporation and drying under hydrogen gas burns off the remaining contaminants and results in pure iridium.
General
Name Iridium
Symbol Ir
Number 77
Chemical series transition metals
Group 9
Period 6
Block d
Appearance silvery white
Standard atomic weight 192.217(3)  g·mol−1
Electron configuration [Xe] 4f14 5d7 6s2
Electrons per shell 2, 8, 18, 32, 15, 2
Atomic properties
Crystal structure cubic face centered
Oxidation states 2, 3, 4, 6 (mildly basic oxide)
Electronegativity 2.20 (scale Pauling)
Ionization energies 1st: 880 kJ/mol
(more) 2nd: 1600 kJ/mol
(more)
Atomic radius 135 pm
Atomic radius (calc.) 180 pm
Covalent radius 137 pm
Van der Waals radius
Physical properties
Phase solid
Density (near r.t.) 22.42  g·cm−3
Liquid density at m.p. 19  g·cm−3
Melting point 2719 K (2446 °C, 4435 °F)
Boiling point 4701 K (4428 °C, 8002 °F)
Critical point
Heat of fusion 41.12  kJ·mol−1
Heat of vaporization 563  kJ·mol−1
Heat capacity (25 °C) 25.10  J·mol−1·K−1
Miscellaneous
Magnetic ordering
Electrical resistivity (20 °C) 47.1 n Ω·m
Thermal conductivity (300 K) 147  W·m−1·K−1
Thermal expansion (25 °C) 6.4  µm·m−1·K−1
Speed of sound (thin rod) (20 °C) 4825 m/s
Young's modulus 528 GPa
Shear modulus 210 GPa
Bulk modulus 320 GPa
Poisson ratio 0.26
Mohs hardness 6.5
Vickers hardness 1760 MPa
Brinell hardness 1670 MPa
CAS registry number 7439-88-5

Print this page Bookmark this page

Hide/View all projects Hide all projects Hide/View all projects

All Projects List
  • Accelerate Rusting
    		•
  • Acids And Bases
    		•
  • Additive Colors
    		•
  • Ant Microphotography
    		•
  • Apple Mummy
    		•
  • Balloon Rocket Car
    		•
  • Barney Banana
    		•
  • Bending Water
    		•
  • Bernoulli’s Principle
    		•
  • Blind Spot in Vision
    		•
  • Boiling Point of Water
    		•
  • Build an Electromagnet
    		•
  • Build an Inclinometer
    		•
  • Caffeine And Typing
    		•
  • Candle Race
    		•
  • Candy Molecules
    		•
  • Capillarity of Soils
    		•
  • Carbon in the Atmosphere
    		•
  • Checking vs. Savings
    		•
  • Chemical Metamorphosis
    		•
  • Clean Cleaners
    		•
  • Cleaning Oil Spills
    		•
  • Climbing Colors
    		•
  • Cloud Cover
    		•
  • CO2 & Photosynthesis
    		•
  • Collecting DNA
    		•
  • Colorful Celery
    		•
  • Coloring Matter in Food
    		•
  • Colors And Temperature
    		•
  • Composition of a Shell
    		•
  • Computer Passwords
    		•
  • Construct a Lung Model
    		•
  • Corrosiveness of Soda
    		•
  • Create a Heat Detector
    		•
  • Create Lightening
    		•
  • Cultivate Slime Molds
    		•
  • Cup of Lava
    		•
  • Dehydrated Potato
    		•
  • Desalinate Sea Water
    		•
  • Detergents and Plants
    		•
  • Dissolving in Liquids
    		•
  • Dissolving Solutes
    		•
  • Distillation of Water
    		•
  • Double Color Flower
    		•
  • Egg in a Bottle
    		•
  • Enzyme Activity
    		•
  • Eroding Away
    		•
  • Erosion Simulator
    		•
  • Evaportating Liquids
    		•
  • Expanding Soap
    		•
  • Exploding Ziploc
    		•
  • Extracting Starch
    		•
  • Fans And Body Temp
    		•
  • Fertilizer & Plants
    		•
  • Filtration of Water
    		•
  • Floating Ball Experiment
    		•
  • Floating Balloon
    		•
  • Fog Formation
    		•
  • Font and Memory
    		•
  • Food and Academics
    		•
  • Friction And Vibration
    		•
  • Fruit Battery Power
    		•
  • Full and Low Fat Foods
    		•
  • Galileo's Experiment
    		•
  • Gas To Liquid
    		•
  • Grape Juice & Cleaners
    		•
  • Gravity and Plants
    		•
  • Green Slime
    		•
  • Growing a Crystal
    		•
  • Growing Bread Mold
    		•
  • Growing Population
    		•
  • Haemoglobin Binding
    		•
  • Hard vs. Soft Water
    		•
  • Homemade Floam
    		•
  • Home-made Geodes
    		•
  • Home-Made Glue #1
    		•
  • Homemade Snowflakes
    		•
  • Home-made Stethoscope
    		•
  • Homemade Volcano
    		•
  • Homemade Windmill
    		•
  • Human Battery Power
    		•
  • Inertia of an Egg
  • Information and CD’s
    		•
  • Invisible Ink
    		•
  • Isolation of Bread Mold
    		•
  • Isolation of DNA
    		•
  • Jar Compass
    		•
  • Lemon Floaties
    		•
  • Levers And Force
    		•
  • Lift an Ice Cube
    		•
  • Light Colors and Plants
    		•
  • Long Lasting Bubbles
    		•
  • Magic Balloons
    		•
  • Magnified Light
    		•
  • Make a Compost Pile
    		•
  • Make a Fuse Model
    		•
  • Make a Parallel Circuit
    		•
  • Make An Elevator
    		•
  • Make Electric Circuits
    		•
  • Make Limestone
    		•
  • Make Objects Float
    		•
  • Make Static Electricity
    		•
  • Make your own sundial
    		•
  • Matchbox Guitar
    		•
  • Math and Gender
    		•
  • Mean, Median and Range
    		•
  • Measuring Air Pollution
    		•
  • Mentos Soda Volcano
    		•
  • Microbial Contaminants
    		•
  • Milky Plastic
    		•
  • Mini Greenhouse
    		•
  • Missing Reflection
    		•
  • Mixing With Water
    		•
  • Molls Experiment
    		•
  • Music and Plants
  • Musical Bottles
    		•
  • Nocturnal Plants
    		•
  • Ocean Life & Oil Spills
    		•
  • Ocean Temperature
  • Optical Mice
    		•
  • Oral Bacteria
    		•
  • Orange Water Volume
    		•
  • Organic vs. Inorganic
    		•
  • Osmosis
    		•
  • Oven Baked Ice Cream
    		•
  • Oxygen & Photosynthesis
    		•
  • Paper Bridge
    		•
  • Paper Marbling
    		•
  • Pascal’s Law
    		•
  • Play-Doh and Volume
    		•
  • Preserve Spider Webs
    		•
  • Pressure Volcano
    		•
  • Pulse Rates
    		•
  • Pythagorean Tuning
    		•
  • Refraction in Water
    		•
  • Rollercoasters & Loops
    		•
  • Rubber Bones
    		•
  • Rubber Heat Reaction
    		•
  • Rubbery Egg
    		•
  • Rust and Moisture
    		•
  • Search Engines
    		•
  • Secondary Colors
    		•
  • Seed Germination
    		•
  • Seed Germination II
    		•
  • Separate Salt And Pepper
    		•
  • Snappy Sounds
    		•
  • Soil Erosion
    		•
  • Soil vs. Hydroponics
    		•
  • Sound Waves
    		•
  • Spectrum through Water
  • Speed of Decomposition
    		•
  • Speed of Dissolving
    		•
  • Spore Prints
    		•
  • Star Observer
    		•
  • Static Electricity
  • Statistics and M&M’s
    		•
  • Stem-less Flowers
    		•
  • Super Strength Egg
    		•
  • Sweet Erosion
    		•
  • Temperature and CPUs
    		•
  • Thirsty Rocks
    		•
  • Tornado Demonstration
    		•
  • Translucent Egg
    		•
  • Transpiration in Plants
    		•
  • Typing and Speed
  • Vibrating Coin
    		•
  • Volcanic Gas
    		•
  • Water and Living Things
    		•
  • Water Displacement
    		•
  • Water Evaporation
    		•
  • Water pH
    		•
  • Your Planetary Age
    		•

    All Categories