|Is Indium a good conductor? |
|Question Date: 2019-12-29|
Indium is a metal, and generally speaking metals are electrically conductive. A material's electrical conductivity is the ease with which electrons can flow within it. Metal conductivity can be attributed to the particular atomic arrangement in metals, which is such that for neighboring atoms, their electron orbitals overlap, effectively delocalizing electrons and allowing them to flow freely in a metal toward the lowest possible electric potential.
By contrast, in less conductive elements such as carbon, atomic bonds are covalent, meaning that electrons are shared between neighboring atoms in a localized way, and they arrange themselves in order to neutralize positive charge in the atomic lattice. The electrons are therefore bound to a certain atom or pair of atoms, and they are less free to flow in the ground state; instead, the application of an electric potential gradient is required to cause many electrons to flow freely in carbon.
The magnitude of conductivity is measured in units of Siemens per meter. This is the inverse of electrical resistivity, which is measured inOhm-meters. Therefore a Siemen is an inverse Ohm.
According to the periodic table, the conductivity of Indium is 1.2 x 107 S/m, which is on the same order of magnitude as other metals, and it is even pretty close to the value for highly conductive copper (5.9 x 107 S/m) and silver (6.2 x 107 S/m).
For perspective, the conductivity of carbon is 105 S/m, about 100 times less than that of Indium, and the conductivity of silicon, which is considered a semiconductor, is 1000 S/m, about 104 times lower than that of Indium.
Indium is a metal, so it is a good conductor of electricity and heat. All metals are conductive, but some are better than others. Indium isn't the best conductor when compared to other metals like copper or silver but it is still much better than non-metals (glass, plastic, silicon, etc). Indium is used in many modern technologies today, including LEDs and solar cells. In my lab, we have glass slides coated with an alloy called Indium Tin Oxide, which is also a conductor.
Indium is a very good conductor of electricity. Specifically, it has a conductivity of 1.2x107 S/m. For reference, Silver (the most conductive element) has a conductivity of 6.2x107 S/m, so it is in the same order of magnitude as the most conductive element. More commonly, indium will be found as part of a chemical compound, which are also often conductive. For example indium tin oxide is used in LCD TVs because it is a very good conductor that can send signals to individual pixels without interference from light.
Pure indium is a good electrical conductor, ranking somewhere between brass and magnesium. In terms of thermal conductivity, indium is not as good as copper, silver, or aluminum, but better than steel.
Indium is a good conductor because it has an unpaired electron in its valence shell (5s). Like most metals, indium's nucleus and core electrons remain as positively charged cores while the valence electron from each atom can easily jump between each core. The ease with which the electrons can jump around means In will be a good conductor.
From this site:
“Indium is is a good conductor of electricity, which can send signals to individual pixels on the screen without light interference from other pixels. The production of indium has increased considerably in recent decades, and China is the world's leading producer of it.”
(Assuming electrical conductivity in this answer.) Indium is more conductive than many materials, but is less conductive than others. As some points of reference, copper, probably the most popular conductor material (and second-most conductive metal), has a conductivity ~6x greater than that of indium; silicon, the popular semiconductor, has a conductivity ~10000x smaller than that of indium; and insulators, which do not conduct to any practical extent, can have conductivities many orders of magnitude smaller than that. [ This page has a nice plot showing resistivity, the inverse of conductivity, of many types of materials.] There is no scientific cutoff for "good" or "bad" conductors, though the conductivity of indium is high enough that it is considered a conductor rather than a semiconductor or an insulator.
Conductors are materials through which electrical charge carriers can move relatively easily. In metals, like indium, this means that the outer (valence) electrons of the atoms are not strongly held to any particular atomic nucleus and will readily drift among the nuclei when an electrical field is applied. Conductivity can vary slightly even for a given element too, mostly based on whether the nuclei get in the way of the moving electrons. For example, conductivity decreases as temperature increases because the nuclei vibrate more rapidly and interfere with the motion of the electrons.
Considering conductivity at a more detailed level (and starting to get into some quantum physics), electrons can only move between vacant energy levels (/states). Metals (or other solids) are conductive because the energies of the lowest-energy unoccupied states overlap with energies of the highest-energy occupied states. (In Band Theory of Solids , these sets of energy levels are called the conduction and valence bands, respectively.) Thus, in conductors only a small amount of energy is needed to cause an electron to move to some other unoccupied state. Conversely, insulators have a large gap between these energy levels and electrons cannot move to open states. Semiconductors have a gap between these bands, but the magnitude is small enough that electrons can be forced across with enough energy input. Within the conductor class there is variation in conductivity because the energy levels differ between elements based on the filled orbitals, crystal structure (arrangement of the atoms in a bulk piece of the material), and nature of the bonding. These produce different " densities of states", which is essentially a measure of how much room is available for electrons to move through. More room to move essentially means more conductivity.
Generally speaking, yes. Indium is considered a conductor. Alloys of Indium are used in a lot of consumer electronics, such as LCDs and solar panels.
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