Copper (II) chloride

From PyroGuide

Formula: CuCl₂

Synonyms: Cupric Chloride,Copper Chloride, Campfire Blue

Description: Not to be mistaken with Copper-I-oxide, copper II chloride is a yellow-brown solid which slowly absorbs moisture to form a blue-green dihydrate. It is used as a color producing agent in some blue star compositions. It is also employed to achieve a blue fire in campfires by soaking wood chips in a water/copper chloride solution and throwing them in the fire. Another way is to sprinkle the powder into the flame. The boilling temperature of CuCl₂ is very low thus it can create great blue fire at low temperature.

Hazards: The gases produced from the burning of CuCl₂ should be avoided. The compound itself is not very poisonous but careful handling is advisable.

Synthesis: Method 1: CuCl₂ can be produced by the reaction between Copper (II) oxide (CuO),Copper carbonate (basic) (CuCO₃), and/or Copper hydroxide (Cu(OH)₂) and Hydrochloric acid. (Do not dilute the acid after dissolving otherwise Copper (I) Chloride will precipitate out) Evaporate to obtain crystals. These will be contaminated with HCl, so dissolve and recrystallize them in distilled water to obtain purer product.

Method 2: Dissolve copper metal in a warm 15% Hydrochloric acid by adding hydrogen peroxide or bubbling air through the solution. Evaporate to obtain crystals. These will be contaminated with HCl, so dissolve and recrystallize them in distilled water to obtain purer product.

Method 3 (Note: I have not tried this method. It will undoubtably be tricky to get right, but hopefully faster than the Method 2): Dissolve copper metal in FeCl₃. Once as much copper as possible will dissolve, decant the solution. Evaporate this until light greenish blue CuCl₂ crystals form, but not lime green FeCl₂ crystals. These will be contaminated with FeCl₂, so dissolve and recrystallize them in distilled water to obtain purer product.

References

Wikipedia[1]

CopperColors blog[2]

Tim Williams[3]