Element 77 of Periodic table is Iridium with atomic number 77, atomic weight 192.217. Iridium, symbol Ir, has a Face Centered Cubic structure and Silver color. Iridium is a transition metal element. Know everything about Iridium Facts, Physical Properties, Chemical Properties, Electronic configuration, Atomic and Crystal Structure.
Iridium is a chemical element with symbol Ir and atomic number 77. A very hard, brittle, silvery-white transition metal of the platinum group, iridium is generally credited with being the second densest element (after osmium) based on measured density, although calculations involving the space lattices of the elements show that iridium is denser. It is also the most corrosion-resistant metal, even at temperatures as high as 2000 °C. Although only certain molten salts and halogens are corrosive to solid iridium, finely divided iridium dust is much more reactive and can be flammable.
Read key information and facts about element Iridium
Name | Iridium |
Atomic Number | 77 |
Atomic Symbol | Ir |
Atomic Weight | 192.217 |
Phase | Solid |
Color | Silver |
Classification | transition metal |
Group in Periodic Table | 9 |
Group Name | cobalt family |
Period in Periodic Table | 6 |
Block in Periodic Table | d-block |
Electronic Configuration | [Xe] 4f14 5d7 6s2 |
Melting Point | 2466 °C |
Boiling Point | 4428 °C |
Electronic Shell Structure | [2, 8, 18, 32, 15, 2] |
CAS Number | CAS7439-88-5 |
Periodic table is arranged by atomic number, number of protons in the nucleus which is same as number of electrons. The atomic number increases from left to right. Periodic table starts at top left ( Atomic number 1) and ends at bottom right (atomic number 118). Therefore you can directly look for atomic number 77 to find Iridium on periodic table.
Another way to read periodic table and locate an element is by using group number (column) and period number (row). To locate Iridium on periodic table look for cross section of group 9 and period 6 in the modern periodic table.
The element Iridium was discovered by Smithson Tennant in year 1803 in France and United Kingdom . Iridium derived its name from Iris, the Greek goddess of the rainbow
The table below shows the abundance of Iridium in Universe, Sun, Meteorites, Earth's Crust, Oceans and Human Body.
Ppb by weight (1ppb =10^-7 %) | |
---|---|
Abundance in Universe | 2×10-7% |
Abundance in Sun | 2×10-7% |
Abundance in Meteorites | 5.4e-07 |
Abundance in Earth's Crust | 4×10-8% |
Abundance in Oceans | N/A |
Abundance in Humans | N/A |
The solid state structure of Iridium is Face Centered Cubic.
The Crystal structure can be described in terms of its unit Cell. The unit Cells repeats itself in three dimensional space to form the structure.
The unit cell is represented in terms of its lattice parameters, which are the lengths of the cell edges Lattice Constants (a, b and c)
a | b | c |
---|---|---|
383.9 | 383.9 | 383.9 pm |
and the angles between them Lattice Angles (alpha, beta and gamma).
alpha | beta | gamma |
---|---|---|
π/2 | π/2 | π/2 |
The positions of the atoms inside the unit cell are described by the set of atomic positions ( xi, yi, zi) measured from a reference lattice point.
The symmetry properties of the crystal are described by the concept of space groups. All possible symmetric arrangements of particles in three-dimensional space are described by the 230 space groups (219 distinct types, or 230 if chiral copies are considered distinct.
Space Group Name | Fm_ 3m |
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Space Group Number | 225 | |
Crystal Structure | Face Centered Cubic |
Iridium atoms have 77 electrons and the electronic shell structure is [2, 8, 18, 32, 15, 2] with Atomic Term Symbol (Quantum Numbers) 4F9/2.
Atomic Number | 77 |
Number of Electrons (with no charge) | 77 |
Number of Protons | 77 |
Mass Number | 192 |
Number of Neutrons | 115 |
Shell structure (Electrons per energy level) | [2, 8, 18, 32, 15, 2] |
Electron Configuration | [Xe] 4f14 5d7 6s2 |
Valence Electrons | 5d7 6s2 |
Oxidation State |
-3;-1
1;2;3;4;5;6;7;8;9 |
Atomic Term Symbol (Quantum Numbers) | 4F9/2 |
Shell Structure of Iridium - Electrons per energy level
n | s | p | d | f | |
---|---|---|---|---|---|
1 | K | 2 | |||
2 | L | 2 | 6 | ||
3 | M | 2 | 6 | 10 | |
4 | N | 2 | 6 | 10 | 14 |
5 | O | 2 | 6 | 7 | |
6 | P | 2 |
The ground state electronic configuration of Neutral Iridium atom is [Xe] 4f14 5d7 6s2. The portion of Iridium configuration that is equivalent to the noble gas of the preceding period, is abbreviated as [Xe]. For atoms with many electrons, this notation can become lengthy and so an abbreviated notation is used.This is important as it is the Valence electrons 4f14 5d7 6s2, electrons in the outermost shell that determine the chemical properties of the element.
Complete ground state electronic configuration for the Iridium atom, Unabbreviated electronic configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d7 6s2
Iridium atomic radius is 180 pm, while it's covalent radius is 137 pm.
Atomic Radius |
180 pm (1.8 Å) |
Atomic Volume | 8.5202570922 cm3 |
Covalent Radius | 137 pm (1.37 Å) |
Van der Waals Radius | N/A |
Neutron Cross Section | 425 σa/barns |
The electron affinity of Iridium is 151 kJ/mol
Valence | 6 |
Electronegativity | 2.2 |
ElectronAffinity | 151 kJ/mol |
Refer to table below for Ionization energies of Iridium
Ionization energy number | Enthalpy - kJ/mol |
---|---|
1 | 880 |
2 | 1.6×103 |
Refer to below table for Iridium Physical Properties
Density | 22.56 g/cm3 |
Molar Volume | 8.5202570922 cm3 |
Young Modulus | 528 GPa |
Shear Modulus | 210 GPa |
Bulk Modulus | 320 GPa |
Poisson Ratio | 0.26 |
Mohs Hardness | 6.5 MPa |
Vickers Hardness | 1760 MPa |
Brinell Hardness | 1670 MPa |
Iridium is Conductor of electricity. Refer to table below for the Electrical properties of Iridium
Electrical Conductivity | 2.1×107 S/m |
Resistivity | 4.7×10-8 m Ω |
Superconducting Point | 0.11 |
Thermal Conductivity | 150 W/(m K) |
Thermal Expansion | 6.4×10-6 K-1 |
Magnetic Type | Paramagnetic |
Curie Point | N/A |
Mass Magnetic Susceptibility | 1.67×10-9 |
Molar Magnetic Susceptibility | 3.21×10-10 |
Volume Magnetic Susceptibility | 3.77e-05 |
Refractive Index | N/A |
Speed of Sound | 4825 m/s |
Refer to table below for Thermal properties of Iridium
Melting Point | 2739 K (2466 °C) |
Boiling Point | 4701 K (4428 °C) |
Critical Temperature | N/A |
Superconducting Point | 0.11 |
Heat of Fusion | 26 kJ/mol |
Heat of Vaporization | 560 kJ/mol |
Heat of Combustion | N/A |
Isotopes of rhodium. Naturally occurring Iridium has 2 stable isotope - 191Ir, 193Ir.
Isotope | Isotope Mass | % Abundance | T half | Decay Mode |
---|---|---|---|---|
164Ir | ||||
165Ir | ||||
166Ir | ||||
167Ir | ||||
168Ir | ||||
169Ir | ||||
170Ir | ||||
171Ir | ||||
172Ir | ||||
173Ir | ||||
174Ir | ||||
175Ir | ||||
176Ir | ||||
177Ir | ||||
178Ir | ||||
179Ir | ||||
180Ir | ||||
181Ir | ||||
182Ir | ||||
183Ir | ||||
184Ir | ||||
185Ir | ||||
186Ir | ||||
187Ir | ||||
188Ir | ||||
189Ir | ||||
190Ir | ||||
191Ir | 37.3% | Stable | N/A | |
192Ir | ||||
193Ir | 62.7% | Stable | N/A | |
194Ir | ||||
195Ir | ||||
196Ir | ||||
197Ir | ||||
198Ir | ||||
199Ir |
CAS Number | CAS7439-88-5 |
RTECS Number | N/A |
DOT Hazard Class | 4.1 |
DOT Numbers | 3089 |
EU Number | N/A |
NFPA Fire Rating | N/A |
NFPA Hazards | N/A |
NFPA Health Rating | N/A |
NFPA Reactivity Rating | N/A |
Autoignition Point | N/A |
Flashpoint | N/A |
List of unique identifiers to search the element in various chemical registry databases
Database | Identifier number |
---|---|
CAS Number - Chemical Abstracts Service (CAS) | CAS7439-88-5 |
CID Number | CID23924 |
Gmelin Number | N/A |
NSC Number | N/A |
RTECS Number | N/A |
Metalloid |
Nonmetals |
Other Nonmetals | |
Halogens | Noble Gas |
Metals |
|
Alkali Metals | Alkaline Earth Metals |
Transition Metals | Post-Transition Metals |
Lanthanide | Actinide |