Plasma — Definition, Formula, Properties & Uses | AllChemicals | AllChemicals

Also Known As	Ionised gas, fourth state of matter, plasma state, arc plasma

What is Plasma?

The fourth state of matter, consisting of a gas of ions and free electrons at very high temperatures. Plasma conducts electricity and responds to magnetic fields. It occurs in stars, lightning, fluorescent lights, and fusion reactors. About 99% of visible matter in the universe is plasma.

Properties & Characteristics

Plasma is the fourth state of matter, consisting of ionised gas (a mixture of free electrons and positive ions) in which the constituent particles respond collectively to electromagnetic fields. Plasma exists at very high temperatures (stars: 10⁶-10⁷ K; fusion reactors: 10⁸ K) or in low-pressure electrical discharges (fluorescent tubes, plasma processing equipment: ~10⁴ K). Natural plasmas include: stars, lightning, flames (weakly), and the sun's corona.

Uses & Applications

Plasmas are used in: semiconductor manufacturing (plasma etching and deposition), surface modification (plasma treatment of polymers for adhesion), plasma arc welding and cutting, lighting (fluorescent lamps, mercury vapour lamps), nuclear fusion research (tokamaks), and sterilisation of heat-sensitive medical devices (hydrogen peroxide plasma sterilisers).

Safety Information

High-temperature plasma arcs (welding, cutting) produce intense UV and visible radiation causing photokeratitis and skin burns. Plasma chemical processes use toxic precursors (silane, NF₃) and generate toxic by-products (HF from plasma etching). RF and microwave plasma generators emit non-ionising radiation. Appropriate shielding and PPE are required for all plasma equipment.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Plasma

Index All "P" terms

Synonyms Ionised gas, fourth state of matter, plasma state, arc plasma

Frequently Asked Questions

What is Plasma?

The fourth state of matter, consisting of a gas of ions and free electrons at very high temperatures. Plasma conducts electricity and responds to magnetic fields. It occurs in stars, lightning, fluorescent lights, and fusion reactors. About 99% of visible matter in the universe is plasma.

What is Plasma used for?

Is Plasma hazardous?

More "P" Terms

P-type Semiconductor Pairing Pairing Energy Palladium Pd Parachor [P] = M(γ)^(1/4) / (ρ_L - ρ_V) Paramagnetic χ_m > 0; unpaired electrons; μ = √(n(n+2)) BM (n = unpaired electrons) Paramagnetism Partial Ionic Character % ionic = (1 - e^(-Δχ²/4)) × 100% Partial Pressure Partial Pressure p_i = x_i × P_total; P_total = Σp_i Particulate Matter Parts Per Million ppm = mg/L (water) or mg/kg; = (mass solute/mass solution) × 10⁶

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