49InIndium114.818 u
Indium (In)
Indium is a post-transition metal with atomic number 49, in period 5 and group 13 of the periodic table. Its atomic mass is 114.818 u and its electron configuration is [Kr] 4d¹⁰ 5s² 5p¹. Solid at 25 °C.
Key facts
| Atomic number | 49 |
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| Atomic mass | 114.818 u |
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| Category | Post-Transition Metal |
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| Period | 5 |
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| Group | 13 |
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| Block | p |
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| Electron configuration | [Kr] 4d¹⁰ 5s² 5p¹ |
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| Electrons per shell | 2, 8, 18, 18, 3 |
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| Electronegativity (Pauling) | 1.78 |
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| Oxidation states | −5, −2, −1, +1, +2, +3common in bold |
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| State at 25 °C | Solid |
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| Melting point | 429.75 K156.6 °C |
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| Boiling point | 2345 K2071.85 °C |
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| Density | 7.31 g/cm³ |
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Atomic properties
| First ionization energy | 5.786 eV |
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| Electron affinity | 28.9 kJ/mol |
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| Atomic radius | 166 pm |
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| Covalent radius | 142 pm |
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| Van der Waals radius | 193 pm |
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| Common ions | In³⁺ |
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| Protons, neutrons, electrons | 49, 66, 49 |
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Physical and thermal properties
| Molar volume | 15.76 cm³/mol |
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| Heat of fusion | 3.26 kJ/mol |
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| Heat of vaporization | 230 kJ/mol |
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| Specific heat | 233 J/(kg·K) |
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| Thermal conductivity | 82 W/(m·K) |
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| Thermal expansion | 3.21 × 10⁻⁵ K⁻¹ |
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| Mohs hardness | 1.2 |
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| Young’s modulus | 11 GPa |
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| Crystal structure | Centered tetragonal |
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| Magnetic type | Diamagnetic |
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Identification and history
| CAS number | 7440-74-6 |
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| Latin name | Indium |
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| Discovered by | F. Reich, H. T. Richter · 1863 |
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| Named by | --- |
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Natural isotopes
| Isotope | Mass (u) | Abundance |
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| 113In | 112.90406 | 4.281 % |
| 115In | 114.903879 | 95.719 % |
Data checked against PubChem (NIH), IUPAC, the NIST Atomic Spectra Database and the IAEA (NUBASE and AME), the same data you see in the app.
A dash (---) means there is no reliable published measurement. The app never makes one up.
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Periodic Table