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.
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)
|SrCO3 (strontium carbonate)|
Li2CO3 (lithium carbonate) LiCl (lithium chloride)
|Orange||Calcium||CaCl2 (calcium chloride)|
|Yellow||Sodium||NaNO3 (sodium nitrate)|
|Green||Barium||BaCl2 (barium chloride)|
|Blue||Copper||CuCl2 (copper chloride), at low temperature|
|Indigo||Cesium||CsNO3 (cesium nitrate)|
|KNO3 (potassium nitrate)|
RbNO3 (rubidium nitrate)
|Gold||Charcoal, iron, or lampblack|
|White||Titanium, aluminum, beryllium, or magnesium powders|
The brightest stars, often called Mag Stars, are fueled by aluminium. Magnesium is rarely used in the fireworks industry due to its lack of ability to form a protective oxide layer. Often an alloy of both metals called magnalium is used.
Many of the chemicals used in the manufacture of fireworks are non-toxic, while many more have some degree of toxicity, can cause skin sensitivity, or exist in dust form and are thereby inhalation hazards. Still others are poisons if directly ingested or inhaled.
The following table is an educational guideline for the chemistry of fireworks.
|Aluminum||Aluminum is used to produce silver and white flames and sparks. It is a common component of sparklers.|
|Barium||Barium is used to create green colors in fireworks, and it can also help stabilize other volatile elements.|
|Carbon||Carbon is one of the main components of black powder, which is used as a propellent in fireworks. Carbon provides the fuel for a firework. Common forms include carbon black, sugar, or starch.|
|Calcium||Calcium is used to deepen firework colors. Calcium salts produce orange fireworks.|
|Chlorine||Chlorine is an important component of many oxidizers in fireworks. Several of the metal salts that produce colors contain chlorine.|
|Cesium||Cesium compounds help to oxidize firework mixtures. Cesium compounds produce an indigo color in fireworks.|
|Copper||Copper produces blue-green colors in fireworks and halides of copper are use to make shades of blue.|
|Iron||Iron is used to produce sparks. The heat of the metal determines the color of the sparks.|
|Potassium||Potassium compounds help to oxidize firework mixtures. Potassium nitrate, potassium chlorate, and potassium perchlorate are all important oxidizers. The potassium content can impart a violet-pink color to the sparks.|
|Lithium||Lithium is a metal that is used to impart a red color to fireworks. Lithium carbonate, in particular, is a common colorant.|
|Magnesium||Magnesium burns a very bright white, so it is used to add white sparks or improve the overall brilliance of a firework.|
|Sodium||Sodium imparts a yellow color to fireworks, however, the color is often so bright that it frequently masks other, less intense colors.|
|Oxygen||Fireworks include oxidizers, which are substances that produce oxygen in order for burning to occur. The oxidizers are usually nitrates, chlorates, or perchlorates. Sometimes the same substance is used to provide oxygen and color.|
|Phosphorus||Phosphorus burns spontaneously in air and is also responsible for some glow in the dark effects. It may be a component of a firework's fuel.|
|Rubidium||Rubidium compounds help to oxidize firework mixtures. Rubidium compounds produce a violet-red color in fireworks.|
|Sulfur||Sulfur is a component of black powder, and as such, it is found in a firework's propellant/fuel.|
|Antimony||Antimony is used to create firework glitter effects.|
|Strontium||Strontium salts impart a red color to fireworks. Strontium compounds are also important for stabilizing fireworks mixtures.|
|Titanium||Titanium metal can be burned as powder or flakes to produce silver sparks.|
|Zinc||Zinc is a bluish white metal that is used to create smoke effects for fireworks and other pyrotechnic devices.|