Copper (II) oxide

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Copper (II) oxide
aka cupric oxide, black copper oxide
Chemical formula CuO
OTP appearance black powder 
Molar Mass(g/mol) 79.545 
Melting Point(°C) 1326 
Boiling Point(°C) 2000 
Density(g/cc) 6.315 
Solubility in water(g/L) 0
NFPA 704
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0
2
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Uses

Primary

Other

  • Catalyst
  • Precursor to cuperammonium for the production of rayon
  • Glass polishing
  • Component of copper-aluminum thermite
  • P-type semiconductor

Natural occurrence

  • Occurs naturally as the rare mineral tenorite

Hazards

Production

Extraction

Synthesis

Template:Reaction

  • Heating copper to 300°C in air produces CuO.
  1. Gather 100ubm of fine copper grains
  2. Heat over a flame in a shallow thin-walled crucible
  3. Repeat
    1. Stir the grains over a steady, strong heat until they become a uniform dark grey or black
      NB: the stirring is vital, or the copper oxide "crust" will prevent air from reaching the inner mass of copper, and solidify the entire mass into a single lump which will be hard to manipulate
    2. Grind filings thoroughly in a mortar and pestle
      NB: this is to crack off any CuO "skin", exposing new copper on the surface of the grain
    3. Weigh the filings.
  4. Until filings weigh close to 125ubm (Cu: ~64g/mol, CuO ~80g/mol
  5. The filings are predominantly copper (II) oxide
As an example, 325mesh (44μm) copper powder will accumulate 10% weight in about 30 minutes in a crucible on a gas stove. The coarser the powder, the smaller the surface area, thus the less oxygen can react with the powder, and the less mass it can gain.

See Also

References