Process materials (gases and chemicals)

What purity does '6N' denote for a gas?

  1. A99.9999%
  2. B96%
  3. C99.6%
Show answer and explanation

Answer: A. 99.9999%

In purity notation, 'N' counts the nines, so 6N means 99.9999%, with six nines. Total impurities are therefore 1 ppm or less. Specialty gases for semiconductors often require even higher purity.

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