Making Fireworks Colorful
Colors in fireworks are usually generated by pyrotechnic stars–usually just called stars–which produce intense light when ignited. Stars contain five basic types of ingredients.
- A fuel which allows the star to burn
- An oxidizer—a compound which produces (usually) oxygen to support the combustion of the fuel
- Color-producing chemicals
- A binder which holds the pellet together.
- A Chlorine Donor which provides chlorine to strengthen the color of the flame. Some times the oxidizer can serve this purpose.
Some of the more common color-producing compounds are tabulated here. The color of a compound in a firework will be the same as its color in a flame test (shown at right). Not all compounds that produce a colored flame are appropriate for coloring fireworks, however. Ideal colorants will produce a pure, intense color when present in moderate concentration.
|Red||Strontium (intense red)
Lithium (medium red)
Li2CO3 ( lithium carbonate )
|Orange||Calcium||CaCl2 ( calcium chloride )|
|Yellow||Sodium||NaNO3 ( sodium nitrate )|
|Green||Barium||BaCl+ ( barium chloride ions)|
|Blue||Copper halides||CuCl2 ( copper chloride ), at low temperature|
|Purple||Potassium or Strontium + Copper||KNO3 ( Potassium Nitrate ) or SrCl+ + CuCl+ ( Strontium Chloride + Copper Chloride )|
|Gold||Charcoal , iron, or lampblack|
|White||Titanium , aluminium , or magnesium powders|