Indium Element Information, Facts, Properties, Trends, Uses, Comparison with other elements
Indium is a chemical element with symbol In and atomic number 49. It is a post-transition metallic element that is rare in Earth's crust. The metal is very soft, malleable and easily fusible, with a melting point higher than sodium, but lower than lithium or tin.
It belongs to group 13 of the periodic table having trivial name triels, icosagens. You can also download Printable Periodic Table of Elements Flashcards for Indium in a PDF format.
Indium Facts
Read key information and facts about element Indium
| Name | Indium |
| Atomic Number | 49 |
| Atomic Symbol | In |
| Atomic Weight | 114.818 |
| Phase | Solid |
| Color | Silver |
| Appearance | silvery lustrous gray |
| Classification | Post Transition Metal |
| Natural Occurance | Primordial |
| Group in Periodic Table | 13 |
| Group Name | boron family |
| Period in Periodic Table | period 5 |
| Block in Periodic Table | p-block |
| Electronic Configuration | [Kr] 4d10 5s2 5p1 |
| Electronic Shell Structure (Electrons per shell) | 2, 8, 18, 18, 3 |
| Melting Point | 429.75 K |
| Boiling Point | 2345 K |
| CAS Number | CAS7440-74-6 |
How to Locate Indium 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 49 to find Indium 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 Indium on periodic table look for cross section of group 13 and period 5 in the modern periodic table.
Indium History
The element Indium was discovered by F. Reich and T. Richter in year 1863 in Germany. Indium was first isolated by T. Richter in 1867. Indium derived its name from indigo.
| Discovered By | F. Reich and T. Richter |
| Discovery Date | 1863 in Germany |
| First Isolation | 1867 |
| Isolated by | T. Richter |
Reich and Richter First identified it in sphalerite by its bright indigo-blue spectroscopic emission line. Richter isolated the metal several years later.
Indium Uses
Indium is majorly used as a doping agent for germanium in the transistor manufacturing process. It is also used to make highly reflective mirrors and low-melting-point alloys.
Indium Presence: Abundance in Nature and Around Us
The table below shows the abundance of Indium 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 Universe | 0.3 | 0.003 |
| Abundance in Sun | 4 | 0.04 |
| Abundance in Meteorites | 45 | 10 |
| Abundance in Earth's Crust | 160 | 30 |
| Abundance in Oceans | 0.0001 | 0.000005 |
| Abundance in Humans | - | - |
Crystal Structure of Indium
The solid state structure of Indium is Centered Tetragonal.
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)
| a | b | c |
|---|---|---|
| 325.23 pm | 325.23 pm | 494.61 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 | I4/mmm |
| Space Group Number | 139 |
| Crystal Structure | Centered Tetragonal |
| Number of atoms per unit cell |
The number of atoms per unit cell in a simple cubic, face-centered cubic and body-centred cubic are 1,4,2 respectively.
Indium Atomic and Orbital Properties
Indium atoms have 49 electrons and the electronic shell structure is [2, 8, 18, 18, 3] with Atomic Term Symbol (Quantum Numbers) 2P1/2.
| Atomic Number | 49 |
| Number of Electrons (with no charge) | 49 |
| Number of Protons | 49 |
| Mass Number | 115 |
| Number of Neutrons | 66 |
| Shell structure (Electrons per energy level) | 2, 8, 18, 18, 3 |
| Electron Configuration | [Kr] 4d10 5s2 5p1 |
| Valence Electrons | 5s2 5p1 |
| Valence (Valency) | 3 |
| Main Oxidation States | 3 |
| Oxidation States | -5, -2, -1, 1, 2, 3 |
| Atomic Term Symbol (Quantum Numbers) | 2P1/2 |
Bohr Atomic Model of Indium - Electrons per energy level
| n | s | p | d | f |
|---|
Ground State Electronic Configuration of Indium - neutral Indium atom
Abbreviated electronic configuration of Indium
The ground state abbreviated electronic configuration of Neutral Indium atom is [Kr] 4d10 5s2 5p1. The portion of Indium configuration that is equivalent to the noble gas of the preceding period, is abbreviated as [Kr]. 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 5s2 5p1, electrons in the outermost shell that determine the chemical properties of the element.
Unabbreviated electronic configuration of neutral Indium
Complete ground state electronic configuration for the Indium atom, Unabbreviated electronic configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p1
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.
Atomic Structure of Indium
Indium atomic radius is 156 pm, while it's covalent radius is 144 pm.
| Atomic Radius Calculated | 156 pm(1.56 Å) |
| Atomic Radius Empirical | 155 pm (1.55 Å) |
| Atomic Volume | 15.707 cm3/mol |
| Covalent Radius | 144 pm (1.44 Å) |
| Van der Waals Radius | 193 pm |
| Neutron Cross Section | 194 |
| Neutron Mass Absorption | 0.06 |
Spectral Lines of Indium - Atomic Spectrum of Indium
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 Indium
Absorption spectrum of Indium
Indium Chemical Properties: Indium Ionization Energies and electron affinity
The electron affinity of Indium is 28.9 kJ/mol.
| Valence | 3 |
| Electronegativity | 1.78 |
| ElectronAffinity | 28.9 kJ/mol |
Ionization Energy of Indium
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 Indium
| Ionization energy number | Enthalpy - kJ/mol |
|---|---|
| 1st | 558.3 |
| 2nd | 1820.7 |
| 3rd | 2704 |
| 4th | 5210 |
Indium Physical Properties
Refer to below table for Indium Physical Properties
| Density | 7.31 g/cm3(when liquid at m.p density is $7.02 g/cm3) |
| Molar Volume | 15.707 cm3/mol |
Elastic Properties
| Young Modulus | 11 |
| Shear Modulus | - |
| Bulk Modulus | - |
| Poisson Ratio | - |
Hardness of Indium - Tests to Measure of Hardness of Element
| Mohs Hardness | 1.2 MPa |
| Vickers Hardness | - |
| Brinell Hardness | 8.83 MPa |
Indium 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).
Indium is a conductor of electricity. Refer to table below for the Electrical properties of Indium
| Electrical conductors | Conductor |
| Electrical Conductivity | 12000000 S/m |
| Resistivity | 8e-8 m Ω |
| Superconducting Point | 3.41 |
Indium Heat and Conduction Properties
| Thermal Conductivity | 82 W/(m K) |
| Thermal Expansion | 0.0000321 /K |
Indium Magnetic Properties
| Magnetic Type | Diamagnetic |
| Curie Point | - |
| Mass Magnetic Susceptibility | -1.4e-9 m3/kg |
| Molar Magnetic Susceptibility | -1.61e-10 m3/mol |
| Volume Magnetic Susceptibility | -0.0000102 |
Optical Properties of Indium
| Refractive Index | - |
Acoustic Properties of Indium
| Speed of Sound | 1215 m/s |
Indium Thermal Properties - Enthalpies and thermodynamics
Refer to table below for Thermal properties of Indium
| Melting Point | 429.75 K(156.60 °C, 313.880 °F) |
| Boiling Point | 2345 K(2071.85 °C, 3761.330 °F) |
| Critical Temperature | - |
| Superconducting Point | 3.41 |
Enthalpies of Indium
| Heat of Fusion | 3.26 kJ/mol |
| Heat of Vaporization | 230 kJ/mol |
| Heat of Combustion | - |
Indium Isotopes - Nuclear Properties of Indium
Indium has 39 isotopes, with between 97 and 135 nucleons. Indium has 1 stable naturally occuring isotopes.
Isotopes of Indium - Naturally occurring stable Isotopes: 113In.
| Isotope | Z | N | Isotope Mass | % Abundance | T half | Decay Mode |
|---|---|---|---|---|---|---|
| 97In | 49 | 48 | 97 | Synthetic | ||
| 98In | 49 | 49 | 98 | Synthetic | ||
| 99In | 49 | 50 | 99 | Synthetic | ||
| 100In | 49 | 51 | 100 | Synthetic | ||
| 101In | 49 | 52 | 101 | Synthetic | ||
| 102In | 49 | 53 | 102 | Synthetic | ||
| 103In | 49 | 54 | 103 | Synthetic | ||
| 104In | 49 | 55 | 104 | Synthetic | ||
| 105In | 49 | 56 | 105 | Synthetic | ||
| 106In | 49 | 57 | 106 | Synthetic | ||
| 107In | 49 | 58 | 107 | Synthetic | ||
| 108In | 49 | 59 | 108 | Synthetic | ||
| 109In | 49 | 60 | 109 | Synthetic | ||
| 110In | 49 | 61 | 110 | Synthetic | ||
| 111In | 49 | 62 | 111 | Synthetic | ||
| 112In | 49 | 63 | 112 | Synthetic | ||
| 113In | 49 | 64 | 113 | 4.29% | Stable | N/A |
| 114In | 49 | 65 | 114 | Synthetic | ||
| 115In | 49 | 66 | 115 | 95.71% | Stable | |
| 116In | 49 | 67 | 116 | Synthetic | ||
| 117In | 49 | 68 | 117 | Synthetic | ||
| 118In | 49 | 69 | 118 | Synthetic | ||
| 119In | 49 | 70 | 119 | Synthetic | ||
| 120In | 49 | 71 | 120 | Synthetic | ||
| 121In | 49 | 72 | 121 | Synthetic | ||
| 122In | 49 | 73 | 122 | Synthetic | ||
| 123In | 49 | 74 | 123 | Synthetic | ||
| 124In | 49 | 75 | 124 | Synthetic | ||
| 125In | 49 | 76 | 125 | Synthetic | ||
| 126In | 49 | 77 | 126 | Synthetic | ||
| 127In | 49 | 78 | 127 | Synthetic | ||
| 128In | 49 | 79 | 128 | Synthetic | ||
| 129In | 49 | 80 | 129 | Synthetic | ||
| 130In | 49 | 81 | 130 | Synthetic | ||
| 131In | 49 | 82 | 131 | Synthetic | ||
| 132In | 49 | 83 | 132 | Synthetic | ||
| 133In | 49 | 84 | 133 | Synthetic | ||
| 134In | 49 | 85 | 134 | Synthetic | ||
| 135In | 49 | 86 | 135 | Synthetic |
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.
| DOT Numbers | 3089 |
| DOT Hazard Class | 4.1 |
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.
| NFPA Fire Rating | N/A | N/A |
| NFPA Health Rating | N/A | N/A |
| NFPA Reactivity Rating | N/A | N/A |
| NFPA Hazards | N/A |
| Autoignition Point | - |
| Flashpoint | - |
Database Search
List of unique identifiers to search the element in various chemical registry databases
| Database | Identifier number |
|---|---|
| CAS Number - Chemical Abstracts Service (CAS) | CAS7440-74-6 |
| RTECS Number | RTECSNL1050000 |
| CID Number | CID5359967 |
| Gmelin Number | - |
| NSC Number | - |
Compare Indium with other elements
Compare Indium with Group 13, Period 5 and Post Transition Metal elements of the periodic table.
Compare Indium with all Group 13 elements
Compare Indium with all Period 5 elements
Compare Indium with all Post Transition Metal elements
Frequently Asked Questions (FAQ)
Find the answers to the most frequently asked questions about Indium