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Ir Iridium
Element Information, Facts, Properties, Trends, Uses, Comparison with other elements

77
Ir
Iridium
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. It is part of group 9 (cobalt family). Know everything about Iridium Facts, Physical Properties, Chemical Properties, Electronic configuration, Atomic and Crystal Structure.
77 Ir - Iridium | SchoolMyKids

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.

It belongs to group 9 of the periodic table having trivial name null. You can also download Printable Periodic Table of Elements Flashcards for Iridium in a PDF format.

Iridium Facts

Read key information and facts about element Iridium

NameIridium
Atomic Number77
Atomic SymbolIr
Atomic Weight192.217
PhaseSolid
ColorSilver
Appearancesilvery white
ClassificationTransition Metal
Natural OccurancePrimordial
Group in Periodic Table9
Group Namecobalt family
Period in Periodic Tableperiod 6
Block in Periodic Tabled-block
Electronic Configuration[Xe] 4f14 5d7 6s2
Electronic Shell Structure (Electrons per shell)2, 8, 18, 32, 15, 2
Melting Point2739 K
Boiling Point4701 K
CAS NumberCAS7439-88-5
123456789101112131415161718
1
1
H
Hydrogen
1.008

Atomic #

Electronic Shell #

Symbol
Name
Atomic Weight
HGas
HgLiquid
CSolid
Metals
Metalloids
NonMetals
Alkali metals
Alkali earth metals
Lanthanoids
Transition metals
Post-transition metals
Other nonmetals
Halogens
Nobel gas
Actinoids
2
He
Helium
4.003
2
3
Li
Lithium
6.941
4
Be
Beryllium
9.012
5
B
Boron
10.811
6
C
Carbon
12.011
7
N
Nitrogen
14.007
8
O
Oxygen
15.999
9
F
Fluorine
18.998
10
Ne
Neon
20.180
3
11
Na
Sodium
22.990
12
Mg
Magnesium
24.305
13
Al
Aluminium
26.982
14
Si
Silicon
28.085
15
P
Phosphorus
30.974
16
S
Sulfur
32.065
17
Cl
Chlorine
35.453
18
Ar
Argon
39.948
4
19
K
Potassium
39.098
20
Ca
Calcium
40.078
21
Sc
Scandium
44.956
22
Ti
Titanium
47.867
23
V
Vanadium
50.941
24
Cr
Chromium
51.996
25
Mn
Manganese
54.938
26
Fe
Iron
55.845
27
Co
Cobalt
58.933
28
Ni
Nickel
58.693
29
Cu
Copper
63.546
30
Zn
Zinc
65.409
31
Ga
Gallium
69.723
32
Ge
Germanium
72.640
33
As
Arsenic
74.922
34
Se
Selenium
78.960
35
Br
Bromine
79.904
36
Kr
Krypton
83.798
5
37
Rb
Rubidium
85.468
38
Sr
Strontium
87.620
39
Y
Yttrium
88.906
40
Zr
Zirconium
91.224
41
Nb
Niobium
92.906
42
Mo
Molybdenum
95.940
43
Tc
Technetium
98
44
Ru
Ruthenium
101.070
45
Rh
Rhodium
102.906
46
Pd
Palladium
106.420
47
Ag
Silver
107.868
48
Cd
Cadmium
112.411
49
In
Indium
114.818
50
Sn
Tin
118.710
51
Sb
Antimony
121.760
52
Te
Tellurium
127.600
53
I
Iodine
126.904
54
Xe
Xenon
131.293
6
55
Cs
Cesium
132.905
56
Ba
Barium
137.327
57 - 71
La - Lu
Lanthanides
72
Hf
Hafnium
178.490
73
Ta
Tantalum
180.948
74
W
Tungsten
183.840
75
Re
Rhenium
186.207
76
Os
Osmium
190.230
77
Ir
Iridium
192.217
78
Pt
Platinum
195.078
79
Au
Gold
196.967
80
Hg
Mercury
200.590
81
Tl
Thallium
204.383
82
Pb
Lead
207.200
83
Bi
Bismuth
208.980
84
Po
Polonium
209
85
At
Astatine
210
86
Rn
Radon
222
7
87
Fr
Francium
223
88
Ra
Radium
226
89 - 103
Ac - Lr
Actinides
104
Rf
Rutherfordium
261
105
Db
Dubnium
262
106
Sg
Seaborgium
266
107
Bh
Bohrium
264
108
Hs
Hassium
269
109
Mt
Meitnerium
268
110
Ds
Darmstadtium
281
111
Rg
Roentgenium
272
112
Cn
Copernicium
285
113
Nh
Nihonium
284
114
Fl
Flerovium
289
115
Mc
Moscovium
288
116
Lv
Livermorium
292
117
Ts
Tennessine
294
118
Og
Oganesson
294
Lanthanides
57
La
Lanthanum
138.905
58
Ce
Cerium
140.116
59
Pr
Praseodymium
140.908
60
Nd
Neodymium
144.240
61
Pm
Promethium
145
62
Sm
Samarium
150.360
63
Eu
Europium
151.964
64
Gd
Gadolinium
157.250
65
Tb
Terbium
158.925
66
Dy
Dysprosium
162.500
67
Ho
Holmium
164.930
68
Er
Erbium
167.259
69
Tm
Thulium
168.934
70
Yb
Ytterbium
173.040
71
Lu
Lutetium
174.967
Actinides
89
Ac
Actinium
227
90
Th
Thorium
232.038
91
Pa
Protactinium
231.036
92
U
Uranium
238.029
93
Np
Neptunium
237
94
Pu
Plutonium
244
95
Am
Americium
243
96
Cm
Curium
247
97
Bk
Berkelium
247
98
Cf
Californium
251
99
Es
Einsteinium
252
100
Fm
Fermium
257
101
Md
Mendelevium
258
102
No
Nobelium
259
103
Lr
Lawrencium
262

How to Locate Iridium on Periodic Table

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.

Iridium History

The element Iridium was discovered by S. Tennant in year 1803 in France and United Kingdom. Iridium was first isolated by S. Tennant in 1803. Iridium derived its name from Iris, the Greek goddess of the rainbow.

Discovered By S. Tennant
Discovery Date 1803 in France and United Kingdom
First Isolation 1803
Isolated by S. Tennant

Tennant had been working on samples of South American platinum in parallel with Wollaston and discovered two new elements, which he named osmium and iridium, and published the iridium results in 1804.

Iridium Uses

Iridium is mostly used as a hardening agent for platinum. This element is also used as an alloy in fountain pen tips and compass bearings, and for the contacts in spark plugs.

Iridium Presence: Abundance in Nature and Around Us

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 %)ppb by atoms (1ppb =10^-7 %)
Abundance in Universe20.01
Abundance in Sun20.01
Abundance in Meteorites55060
Abundance in Earth's Crust0.40.05
Abundance in Oceans--
Abundance in Humans--

Crystal Structure of Iridium

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.

Unit Cell Parameters

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)

abc
383.9 pm383.9 pm383.9 pm

and the angles between them Lattice Angles (alpha, beta and gamma).

alphabetagamma
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 NameFm_ 3m
Space Group Number225
Crystal StructureFace Centered Cubic
Number of atoms per unit cell4
77 Ir Iridium - Crystal Structure | SchoolMyKids

The number of atoms per unit cell in a simple cubic, face-centered cubic and body-centred cubic are 1,4,2 respectively.

Iridium Atomic and Orbital Properties

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 Number77
Number of Electrons (with no charge)77
Number of Protons77
Mass Number192
Number of Neutrons115
Shell structure (Electrons per energy level)2, 8, 18, 32, 15, 2
Electron Configuration[Xe] 4f14 5d7 6s2
Valence Electrons5d7 6s2
Valence (Valency)6
Main Oxidation States3, 4
Oxidation States-3, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
Atomic Term Symbol (Quantum Numbers)4F9/2

Bohr Atomic Model of Iridium - Electrons per energy level

77 Ir Iridium Electron Shell Structure | SchoolMyKids
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Ground State Electronic Configuration of Iridium - neutral Iridium atom

Abbreviated electronic configuration of Iridium

The ground state abbreviated 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 5d7 6s2, electrons in the outermost shell that determine the chemical properties of the element.

Unabbreviated electronic configuration of neutral Iridium

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

Electrons are filled in atomic orbitals as per the order determined by the Aufbau principle, Pauli Exclusion Principle and Hund’s Rule.

  • As per the Aufbau principle the electrons will occupy the orbitals having lower energies before occupying higher energy orbitals. According to this principle, electrons are filled in the following order: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p…
  • The Pauli exclusion principle states that a maximum of two electrons, each having opposite spins, can fit in an orbital.
  • Hund's rule states that every orbital in a given subshell is singly occupied by electrons before a second electron is filled in an orbital.
  • Electron configuration of Iridium
    Atomic Structure of Iridium

    Iridium atomic radius is 180 pm, while it's covalent radius is 137 pm.

    Atomic Radius Calculated

    180 pm(1.8 Å)

    Atomic Radius Empirical

    135 pm (1.35 Å)

    Atomic Volume8.5203 cm3/mol
    Covalent Radius137 pm (1.37 Å)
    Van der Waals Radius-
    Neutron Cross Section425
    Neutron Mass Absorption 0.08

    Spectral Lines of Iridium - Atomic Spectrum of Iridium

    A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to identify atoms and molecules.

    Spectral lines are the result of interaction between a quantum system and a single photon. A spectral line may be observed either as an emission line or an absorption line.

    Spectral lines are highly atom-specific, and can be used to identify the chemical composition of any medium. Several elements, including helium, thallium, and caesium, were discovered by spectroscopic means. They are widely used to determine the physical conditions of stars and other celestial bodies that cannot be analyzed by other means.

    Emission spectrum of Iridium

    Emission Spectrum of Iridium | SchoolMyKids

    Absorption spectrum of Iridium

    Absorption Spectrum of Iridium | SchoolMyKids

    Iridium Chemical Properties: Iridium Ionization Energies and electron affinity

    The electron affinity of Iridium is 151 kJ/mol.

    Valence6
    Electronegativity2.2
    ElectronAffinity151 kJ/mol

    Ionization Energy of Iridium

    Ionization energy is the amount of energy required to remove an electron from an atom or molecule.in chemistry, this energy is expresed in kilocalories per mole (kcal/mol) or kilojoules per mole (kJ/mol).

    Refer to table below for Ionization energies of Iridium

    Ionization energy numberEnthalpy - kJ/mol
    1st880
    2nd1600

    Iridium Physical Properties

    Refer to below table for Iridium Physical Properties

    Density22.56 g/cm3(when liquid at m.p density is $19 g/cm3)
    Molar Volume8.5203 cm3/mol

    Elastic Properties

    Young Modulus528
    Shear Modulus210 GPa
    Bulk Modulus 320 GPa
    Poisson Ratio0.26

    Hardness of Iridium - Tests to Measure of Hardness of Element

    Mohs Hardness6.5 MPa
    Vickers Hardness1760 MPa
    Brinell Hardness1670 MPa

    Iridium Electrical Properties

    Electrical resistivity measures element's electrical resistance or how strongly it resists electric current.The SI unit of electrical resistivity is the ohm-metre (Ω⋅m). While Electrical conductivity is the reciprocal of electrical resistivity. It represents a element's ability to conduct electric current. The SI unit of electrical conductivity is siemens per metre (S/m).

    Iridium is a conductor of electricity. Refer to table below for the Electrical properties of Iridium

    Electrical conductors Conductor
    Electrical Conductivity21000000 S/m
    Resistivity4.7e-8 m Ω
    Superconducting Point0.11

    Iridium Heat and Conduction Properties

    Thermal Conductivity150 W/(m K)
    Thermal Expansion0.0000064 /K

    Iridium Magnetic Properties

    Magnetic TypeParamagnetic
    Curie Point-
    Mass Magnetic Susceptibility1.67e-9 m3/kg
    Molar Magnetic Susceptibility3.21e-10 m3/mol
    Volume Magnetic Susceptibility0.0000377

    Optical Properties of Iridium

    Refractive Index-

    Acoustic Properties of Iridium

    Speed of Sound4825 m/s

    Iridium Thermal Properties - Enthalpies and thermodynamics

    Refer to table below for Thermal properties of Iridium

    Melting Point2739 K(2465.85 °C, 4470.530 °F)
    Boiling Point4701 K(4427.85 °C, 8002.130 °F)
    Critical Temperature-
    Superconducting Point0.11

    Enthalpies of Iridium

    Heat of Fusion26 kJ/mol
    Heat of Vaporization560 kJ/mol
    Heat of Combustion-

    Iridium Isotopes - Nuclear Properties of Iridium

    Iridium has 36 isotopes, with between 164 and 199 nucleons. Iridium has 2 stable naturally occuring isotopes.

    Isotopes of Iridium - Naturally occurring stable Isotopes: 191Ir, 193Ir.

    IsotopeZNIsotope Mass% AbundanceT halfDecay Mode
    164Ir7787164Synthetic
    165Ir7788165Synthetic
    166Ir7789166Synthetic
    167Ir7790167Synthetic
    168Ir7791168Synthetic
    169Ir7792169Synthetic
    170Ir7793170Synthetic
    171Ir7794171Synthetic
    172Ir7795172Synthetic
    173Ir7796173Synthetic
    174Ir7797174Synthetic
    175Ir7798175Synthetic
    176Ir7799176Synthetic
    177Ir77100177Synthetic
    178Ir77101178Synthetic
    179Ir77102179Synthetic
    180Ir77103180Synthetic
    181Ir77104181Synthetic
    182Ir77105182Synthetic
    183Ir77106183Synthetic
    184Ir77107184Synthetic
    185Ir77108185Synthetic
    186Ir77109186Synthetic
    187Ir77110187Synthetic
    188Ir77111188Synthetic
    189Ir77112189Synthetic
    190Ir77113190Synthetic
    191Ir7711419137.3%StableN/A
    192Ir77115192SyntheticStable
    193Ir7711619362.7%StableN/A
    194Ir77117194Synthetic
    195Ir77118195Synthetic
    196Ir77119196Synthetic
    197Ir77120197Synthetic
    198Ir77121198Synthetic
    199Ir77122199Synthetic

    Regulatory and Health - Health and Safety Parameters and Guidelines

    The United States Department of Transportation (DOT) identifies hazard class of all dangerous elements/goods/commodities either by its class (or division) number or name. The DOT has divided these materials into nine different categories, known as Hazard Classes.

    Flammable solids, self-reactive substances and solid desensitized explosives

    NFPA 704 is a Standard System for the Identification of the Hazards of Materials for Emergency Response. NFPA is a standard maintained by the US based National Fire Protection Association.

    The health (blue), flammability (red), and reactivity (yellow) rating all use a numbering scale ranging from 0 to 4. A value of zero means that the element poses no hazard; a rating of four indicates extreme danger.

    Autoignition Point-
    Flashpoint-

    Database Search

    List of unique identifiers to search the element in various chemical registry databases

    DatabaseIdentifier number
    CAS Number - Chemical Abstracts Service (CAS)CAS7439-88-5
    RTECS Number-
    CID Number CID23924
    Gmelin Number-
    NSC Number-

    Compare Iridium with other elements

    Compare Iridium with all Group 9 elements

    Compare Iridium with all Period 6 elements

    Compare Iridium with all Transition Metal elements

    FAQs

    What is the electronic configuration of Iridium?

    The electronic configuration of Iridium is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d7 6s2.

    What is the abbreviated electronic configuration of Iridium?

    The abbreviated electronic configuration of Iridium is [Xe] 4f14 5d7 6s2. To form abbreviated notation of electronic configuration, the completely filled subshells are replaced by the noble gas of the preceding period in square brackets.

    What is the symbol of Iridium?

    Symbol of Iridium is Ir. Iridium is a chemical element with symbol Ir and atomic number 77.

    What is the position of Iridium in the Periodic Table?

    Iridium is a chemical element with the symbol Ir and atomic number 77. Iridium is the 77 element on the periodic table. It is located in group 9 and period 6 in the modern periodic table.

    What is the atomic number of Iridium?

    The atomic number of Iridium is 77.

    What is the color of Iridium?

    Iridium is of Silver color.

    Who discovered Iridium?

    The element Iridium was discovered by S. Tennant in year 1803 in France and United Kingdom. Iridium was first isolated by S. Tennant in 1803.

    How many valence electrons does a Iridium atom have?

    Iridium has 6 valence electrons. Iridium has 77 electrons out of which 6 valence electrons are present in the 5d7 6s2 outer orbitals of atom.

    What is the melting Point of Iridium?

    Melting Point of Iridium is 2739 K.

    What is the boiling Point of Iridium?

    Boiling Point of Iridium is 4701 K.

    What is the melting Point of Iridium in Kelvin?

    Melting Point of Iridium in Kelvin is 2739 K.

    What is the boiling Point of Iridium in Kelvin?

    Boiling Point of Iridium in Kelvin is 4701 K.

    What is the melting Point of Iridium in Celsius?

    Melting Point of Iridium in Celsius is 2465.85 °C.

    What is the boiling Point of Iridium in Celsius?

    Boiling Point of Iridium in Celsius is 4427.85 °C.

    What is the melting Point of Iridium in Fahrenheit?

    Melting Point of Iridium in Fahrenheit is 4470.53 °F.

    What is the boiling Point of Iridium in Fahrenheit?

    Boiling Point of Iridium in Fahrenheit is 8002.13 °F.

    What is the electronic configuration of Iridium 77?

    The electronic configuration of Iridium will be 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d7 6s2.

    How do you write the electron configuration for Iridium?

    The electronic configuration of Iridium will be 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d7 6s2.