Pyrotechnic Colorant

A pyrotechnic colorant is a chemical compound which causes a flame to burn with a particular color. These are used to create the colors in pyrotechnic compositions like fireworks and colored fires. The color-producing species are usually created from other chemicals during the reaction. Metal salts are commonly used; elemental metals are used rarely (e.g. copper for blue flames).

The color of the flame is dependent on the metal cation; the anion of the salt has very little direct influence. The anions however influence the flame temperature, both by increasing it (e.g. nitrates, chlorates) and decreasing it (e.g. carbonates, oxalates), indirectly influencing the flame brightness and brilliancy. For temperature-decreasing additives, the limit of colorant may be about 10–20 wt.% of the composition.

Some common examples are:

Color Compound name Chemical formula Notes
Red Strontium nitrate Sr(NO3)2 Common. Used with chlorine donors. Excellent red, especially with metal fuels. Used in many compositions including road flares.
Red Strontium carbonate SrCO3 Common. Produces good red. Slows burning of compositions, decomposes yielding carbon dioxide. Fire retardant in gunpowders. Inexpensive, non-hygroscopic, neutralizes acids. Superior over strontium oxalate in absence of magnesium.
Red Strontium oxalate SrC2O4 Decomposes yielding carbon dioxide and carbon monoxide. In presence of magnesium fuel, carbon monoxide reduces particles of magnesium oxide, yielding gaseous magnesium and eliminating the black body radiation of the MgO particles, resulting in clearer color.
Red Strontium sulfate SrSO4 Common. High-temperature oxidizer. Used in strobe mixtures and some metal-based red compositions.
Red Strontium chloride SrCl2 Common. Produces bright red flame.
Orange Calcium carbonate CaCO3 Produces orange flame. Yields carbon dioxide on decomposition. Often used in toy fireworks as a substitute for strontium.
Orange Calcium chloride CaCl2
Orange Calcium sulfate CaSO4 High-temperature oxidizer. Excellent orange source in strobe compositions.
Orange Hydrated calcium sulfate CaSO4(H2O)x*
Gold/Yellow Charcoal powder C
Gold/Yellow Iron powder with oxygen based carbon OC12 Fe+C
Yellow Sodium bicarbonate NaHCO3 Compatible with potassium chlorate. Less burning rate decrease than sodium carbonate. Incompatible with magnesium and aluminium, reacts evolving hydrogen gas.
Yellow Sodium carbonate Na2CO3 Hygroscopic. Significantly decreases burning rate, decomposes evolving carbon dioxide. Strongly alkaline. Very effective colorant, can be used in small amounts. Corrodes magnesium and aluminium, incompatible with them.
Yellow Sodium chloride NaCl Loses hygroscopicity on heating. Corrodes metals.
Yellow Sodium oxalate Na2C2O4 Non-hygroscopic. Slightly reacts with magnesium, no reaction with aluminium.
Yellow Sodium nitrate NaNO3 Also acts as oxidizer. Bright flame, used for illumination.
Yellow Cryolite Na3AlF6 One of the few sodium salts that is nonhygroscopic and insoluble in water.
Green Barium chloride BaCl2
Green Barium chlorate Ba(ClO3)2 Classic exhibition green with shellac fuel. Sensitive to shock and friction. Oxidizer.
Green Barium carbonate BaCO3 Pretty color when ammonium perchlorate is used as oxidizer.
Green Barium nitrate Ba(NO3)2 Not too strong effect. With chlorine donors yields green color, without chlorine burns white. In green compositions usually used with perchlorates.
Green Barium oxalate BaC2O4
Blue Copper(I) chloride CuCl Richest blue flame. Almost insoluble in water.
Blue Copper(I) oxide Cu2O Lowest cost blue colorant.
Blue Copper(II) oxide CuO Used with chlorine donors. Excellent in composite stars.
Blue Copper carbonate CuCO3 Best when used with ammonium perchlorate.
Blue Basic copper carbonate CuCO3·Cu(OH)2, 2 CuCO3·Cu(OH)2 Occurs naturally as malachite and azurite. Good with ammonium perchlorate and for high-temperature flames with presence of hydrogen chloride. Not easily airborne, less poisonous than Paris Green.
Blue Copper oxychloride 3CuO·CuCl2 Good blue colorant with suitable chlorine donor.
Blue Paris Green Cu(CH3COO)2.3Cu(AsO2)2 Copper acetoarsenite, Emerald Green. Toxic. With potassium perchlorate produces the best blue colors. Non-hygroscopic. Fine powder readily becomes airborne; toxic inhalation hazard. Used in majority of Japanese blue compositions as it gives very pretty color.
Blue Copper arsenite CuHAsO3 Almost non-hygroscopic. Almost as good colorant as copper acetoarsenite. Toxic. Can be used with chlorate oxidizers.
Blue Copper sulfate CuSO4·5 H2O Can be used with nitrates and perchlorates. Acidic, incompatible with chlorates. With red phosphorus in presence of moisture liberates heat, may spontaneously ignite. Less expensive than copper acetoarsenite. Anhydrous copper sulfate is hygroscopic, can be used as a desiccant. With ammonium perchlorate produces almost as pretty blue color as achievable with copper acetoarsenite.
Blue Copper metal Cu Rarely used, other compounds are easier to work with. Yields pretty blue color in ammonium perchlorate based compositions; but reacts with ammonium perchlorate and liberates ammonia in presence of moisture. The composition must be kept dry.
Purple Combination of red and blue compounds Sr+Cu
Purple Rubidium compounds Rb rarely used
Silver/White Aluminium powder Al
Silver/White Magnesium powder Mg
Silver/White Titanium powder Ti
Silver/White Antimony (III) sulfide Sb2S3
Infrared Caesium nitrate CsNO3 two powerful spectral lines at 852.113 nm and 894.347 nm
Infrared Rubidium nitrate RbNO3

The * indicates that the compound will burn orange where x=0,2,3,5.

Read more about Pyrotechnic Colorant:  Radiating Species

Other articles related to "pyrotechnic colorant, colorant":

Pyrotechnic Colorant - Radiating Species
... balance of the composition in presence of organic fuels, or by addition of the colorant in the form of an oxalate, which decomposes to carbon dioxide and carbon monoxide the carbon monoxide ...