Copper (II) chloride

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Copper (II) chloride
aka cupric chloride
Chemical formula CuCl2
OTP appearance yellow-brown solid 
Molar Mass(g/mol) 134.45 
Melting Point(°C) 498 
Boiling Point(°C) 993 (decomp) 
Density(g/cc) 3.386 
Solubility in water(g/L) 757 
Solubility in ethanol(g/L) 530 
Solubility in methanol(g/L) 680 
Solubility in ether(g/L) 1.1 
Solubility in acetone(g/L) 30
NFPA 704



Natural occurrence


Soluble copper compounds are toxic to mammals and can be deadly to fish.



The main routes are divided by the source of the chloride ion. The simplest is hydrochloric acid:

via hydrochloric acid

metallic copper
  • Bubble air through copper metal immersed in hydrochloric acid. This will not work without the air, and even then it takes days. This may go in two separate steps, first to copper (I) chloride, and thence to copper(II) chloride, shown separately below.
    4 Cu + 4 HCl + O2 4 CuCl + 2 H2O // from copper(0) to copper (I)
    4 CuCl + 4 HCl + O2 4 CuCl2 + 2 H2O // from copper(I) to copper (II)
copper (II) minerals
copper (I) chloride
  • Bubble air through copper (I) chloride in hydrochloric acid. This will not work without the air, and even then it takes days.
    4 CuCl + 4 HCl + O2 4 CuCl2 + 2 H2O // from (I) to (II)

via sodium chloride

Relative Solubilities
  water ethanol
g/L M g/L M
copper chloride 757 5.63 530.00 3.94
sodium chloride 359 6.10 0.65 0.01
copper acetate 65 0.36 71.40 0.39
sodium acetate 1233 15.00 23.00 0.28
copper sulfate 200 1.26 ins 0
sodium sulfate 139 1.02 ins 0
0.035M (100ml) scale
  1. Gather 6.7g of copper (II) acetate monohydrate
  2. Heat to 160°C (325F) for 10 minutes to drive off the water
  3. Measure mass again: should be 6.33g
  4. Dissolve in 100ml dried ethanol (saturated limit, 0.35M)
  5. Transfer ethanol to separation funnel
  6. Prepare saturated saline solution (6M)
  7. Repeat
    1. Add 5.7ml of saturated saline solution to ethanol in sep funnel, shaking regularly
    2. Draw off aqueous layer and evaporate
      NB: Should contain mostly sodium acetate, less sodium chloride.
  8. Until mostly sodium acetate remains
  9. Evap the ethanol layer, leaving mostly copper chloride

When using salt as a source of chlorine, choose an anion whose copper salt that is more soluble in water than ethanol, such as copper (II) acetate or copper sulfate, and preferably an anion for which the sodium salt also prefers water. Mix them in a water/ethanol solution, and allow the copper chloride to dominate the ethanol phase.

  1. Combine a water-soluble copper (II) salt (e.g. copper (II) acetate) with sodium chloride in a strong (80%+) ethanol/water mixture. The products are copper (II) acetate, sodium chloride, sodium acetate, and the target copper (II) chloride.
  2. Repeat
    1. Decant ethanol layer
    2. Distill to dryness
    3. Return distillate to mother liquor
    4. Filter residue from distillation
    5. Wash with cold dry ethanol
    6. Discard white residue (CuAc, NaAc, NaCl)
    7. Evaporate leaving mostly CuCl2
  3. Until the ethanol layer stops containing much
Continuous process

By leveraging the salting-out effect of the water-ethanol mix, it's possible to create a cycle, where cold CuCl2-rich ethanol solution is transported by gravity to an evaporation unit which directs the ethanol vapors as they condense back to the source salt mix. This results in the acumulation of copper chloride in the evaporation unit


  • There is an exothermic reaction with aluminum and aluminum oxide


recrystallize from hot dilute aqueous HCl by cooling in a calcium chloride-ice bath


  • Do not store with excess copper. This can result in decomposition to copper (I) chloride:
    Cu + CuCl2 2 CuCl
  • Do not store in acidic conditions.


See Also