Magnesium is a conductive metal. This is because it has two valence electrons that readily conduct electricity and heat when they dissolve or attain a molten (ionic) state.
The metal exhibits a covalent bond in its solid state and will not conduct. This is the case for magnesium oxide or sulfate, which do not conduct electricity or heat.
To better understand the relationship between magnesium and conductivity, this guide will walk you through why magnesium only conducts in a molten state and not in a solid state.
You will also learn about its essential properties and structure, electrical and thermal conductivity, and real-life applications.
Properties and Structure of Magnesium
- Magnesium is a lightweight and slightly hard metal.
- It can form ionic and covalent bonds.
- The metal has a hexagonal and tightly-packed structure with an atomic number of 12.
- It has a covalent radius of about 140 pm.
- Magnesium readily reacts with oxygen in the atmosphere at room temperature to form oxides.
- The metal has a melting point of 651°C and a boiling point of 1100°C.
- Magnesium is highly flammable, producing white light (or fire).
How Does Magnesium Conduct Electricity?
Magnesium is only conductive in a molten, mixed, or dissolved state. In this ionic state, the metal dissociates into charged particles in the presence of an electric potential.
This results in excitation and increased vibration, which is necessary for any metal to conduct electricity. However, magnesium readily reacts with oxygen, nitrogen, and carbon dioxide, so its electrical conductivity is lower than that of superconductors like silver and copper.
What is the Electrical Conductivity of Magnesium?
The electrical conductivity of any material is a measure of how much electricity it will allow to pass through it. For magnesium, this is rated at 0.226×106 /cm ohm.
Since this is also a measure of the ratio of the current density per length of the conductor, it can be calculated using the formula:
σ = l/RA
Where:
- σ = Electrical conductivity
- R = Resistance of the material
- A = Cross-sectional area of material
- L = Length of material
Does Magnesium Oxide Conduct Electricity?
Unlike pure magnesium, magnesium oxide is not conductive in either a solid or dissolved state. Magnesium becomes an oxide when it shares its two valence electrons with an oxygen atom (with a deficiency of two electrons already).
Hence, the oxide has a neutral charge and will not conduct electricity.
Does Magnesium Sulfate Conduct Electricity?
Magnesium sulfate does not conduct electricity. This is similar to why magnesium oxide does not conduct electricity—the neutralization of charges in the ionic lattice.
In the case of magnesium sulfate, the oxidation state of sulfate is -2. This is neutralized by magnesium ions. However, when dissolved in an aqueous solution, it dissociates into ions that can conduct electricity.
Does Magnesium Conduct Heat?
Magnesium is a good conductor of heat thanks to its 2 valence electrons which vibrate freely in high temperatures. The thermal conductivity of magnesium is 156 W/m.K.
This value is lower than good thermal conductors like copper (398 W/m.K) and aluminum (237 W/m.K).
Uses of Magnesium
- Magnesium is a great alloying agent. It is less dense than aluminum and improves aluminum’s mechanical and welding characteristics, as seen in car and aircraft applications.
- The metal also helps produce lightweight luggage, laptops, car seats, power tools, and cameras.
- You can also add magnesium to molten iron and steel to remove sulfur.
- Magnesium is used for producing fireworks, flares, and sparklers since it is very flammable and burns easily in the air.
- Magnesium sulfate feature sometimes features as a mordant for dyes.
- Their hydroxide helps in retarding fire in plastics.
- Heat-resistant bricks used in molding fireplaces and furnaces also feature magnesium oxide.
- You can also include magnesium in cattle feed and fertilizers.
- Magnesium sulfate (in the form of Epsom salts), magnesium chloride, magnesium hydroxide (milk of magnesia), and magnesium citrate are all useful in medicine.
- Manufacturing industries also value organic magnesium compounds like Grignard reagents.
FAQs
Is magnesium used for electrical wires?
Yes, magnesium can be used in electrical wires. Most absorbable and restorative medical devices contain them.
Does magnesium react with water?
Magnesium reacts with hot water or water vapor to form Magnesium hydroxide and hydrogen gas.
Is magnesium flammable?
Pure magnesium is highly flammable in powder, molten, and ribbon form. This is why most magnesium operations are done with safety glasses and gloves.
Conclusion
It is safe to say that magnesium is conductive. The metal only conducts electricity and heat to a certain degree in a molten or ionic state. Unlike metals like copper and aluminum, magnesium has a higher electrical resistivity. Hence, it is not the most suitable metal for electrical wires.
For magnesium to be used in electrical equipment, it must be treated to remove any oxide before any connection occurs. This connection must also be airtight to prevent a relapse.
Despite this process’ expensive nature, magnesium’s conductivity remains poor within the circuit. Engineers prefer other metals such as copper and aluminum, with magnesium mainly featured as an alloying material.
I hope you found this article helpful. Explore the guide on metals that conduct electricity to understand metals and their electrical conductivities fully.
Thanks for reading.