A pyrotechnic colorant is a chemical compound

Chemical compound

A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...

 which causes a flame

Flame

A flame is the visible , gaseous part of a fire. It is caused by a highly exothermic reaction taking place in a thin zone...

 to burn with a particular color

Color

Color or colour is the visual perceptual property corresponding in humans to the categories called red, green, blue and others. Color derives from the spectrum of light interacting in the eye with the spectral sensitivities of the light receptors...

. These are used to create the colors in pyrotechnic composition

Pyrotechnic composition

A pyrotechnic composition is a substance or mixture of substances designed to produce an effect by heat, light, sound, gas or smoke or a combination of these, as a result of non-detonative self-sustaining exothermic chemical reactions...

s like fireworks and colored fire

Colored fire

Colored fire is a common pyrotechnic effect used in stage productions, fireworks and by fire performers the world over. Generally, the color of a flame may be red, orange, yellow, or white, and is dominated by blackbody radiation from soot and steam...

s. 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 Strontium nitrate Strontium nitrate is an inorganic compound with the formula Sr2. This colourless solid is used as an colorant in pyrotechnics.- Preparation:Strontium nitrate is typically generated by the reaction of nitric acid on strontium carbonate.....	Sr(NO3)2	Common. Used with chlorine donors. Excellent red, especially with metal fuels. Used in many compositions including road flares.
Red	Strontium carbonate Strontium carbonate Strontium carbonate is the carbonate salt of strontium that has the appearance of a white or grey powder. It occurs in nature as the mineral strontianite.- Chemical properties :...	SrCO3	Common. Produces good red. Slows burning of compositions, decomposes yielding carbon dioxide. Fire retardant in gunpowder Gunpowder Gunpowder, also known since in the late 19th century as black powder, was the first chemical explosive and the only one known until the mid 1800s. It is a mixture of sulfur, charcoal, and potassium nitrate - with the sulfur and charcoal acting as fuels, while the saltpeter works as an oxidizer... s. 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 Strontium sulfate Strontium sulfate is the sulfate salt of strontium. It is a white crystalline powder and occurs in nature as the mineral celestine. It is poorly soluble in water to the extent of 1 part in 8,800. It is more soluble in dilute HCl and nitric acid and appreciably soluble in alkali chloride solutions...	SrSO4	Common. High-temperature oxidizer. Used in strobe mixtures and some metal-based red compositions.
Red	Strontium chloride Strontium chloride Strontium chloride is a salt of strontium and chloride. It is a typical salt, forming neutral aqueous solutions. Like all compounds of Sr, this salt emits a bright red colour in a flame; in fact is used as a source of redness in fireworks...	SrCl2	Common. Produces bright red flame.
Orange	Calcium carbonate Calcium carbonate Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime,...	CaCO3	Produces orange flame. Yields carbon dioxide on decomposition. Often used in toy fireworks as a substitute for strontium.
Orange	Calcium chloride Calcium chloride Calcium chloride, CaCl2, is a salt of calcium and chlorine. It behaves as a typical ionic halide, and is solid at room temperature. Common applications include brine for refrigeration plants, ice and dust control on roads, and desiccation...	CaCl2
Orange	Calcium sulfate Calcium sulfate Calcium sulfate is a common laboratory and industrial chemical. In the form of γ-anhydrite , it is used as a desiccant. It is also used as a coagulant in products like tofu. In the natural state, unrefined calcium sulfate is a translucent, crystalline white rock...	CaSO4	High-temperature oxidizer. Excellent orange source in strobe compositions.
Orange	Hydrated calcium sulfate Calcium sulfate Calcium sulfate is a common laboratory and industrial chemical. In the form of γ-anhydrite , it is used as a desiccant. It is also used as a coagulant in products like tofu. In the natural state, unrefined calcium sulfate is a translucent, crystalline white rock...	CaSO4(H2O)x*
Gold/Yellow	Charcoal Charcoal Charcoal is the dark grey residue consisting of carbon, and any remaining ash, obtained by removing water and other volatile constituents from animal and vegetation substances. Charcoal is usually produced by slow pyrolysis, the heating of wood or other substances in the absence of oxygen...  powder	C
Gold/Yellow	Iron Iron Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...  powder with oxygen based carbon Carbon Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...  OC12	Fe+C
Yellow	Sodium bicarbonate Sodium bicarbonate Sodium bicarbonate or sodium hydrogen carbonate is the chemical compound with the formula Na HCO3. Sodium bicarbonate is a white solid that is crystalline but often appears as a fine powder. It has a slightly salty, alkaline taste resembling that of washing soda . The natural mineral form is...	NaHCO3	Compatible with potassium chlorate. Less burning rate decrease than sodium carbonate. Incompatible with magnesium and aluminium, reacts evolving hydrogen gas.
Yellow	Sodium carbonate Sodium carbonate Sodium carbonate , Na2CO3 is a sodium salt of carbonic acid. It most commonly occurs as a crystalline heptahydrate, which readily effloresces to form a white powder, the monohydrate. Sodium carbonate is domestically well-known for its everyday use as a water softener. It can be extracted from the...	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 Sodium chloride Sodium chloride, also known as salt, common salt, table salt or halite, is an inorganic compound with the formula NaCl. Sodium chloride is the salt most responsible for the salinity of the ocean and of the extracellular fluid of many multicellular organisms...	NaCl	Loses hygroscopicity on heating. Corrodes metals.
Yellow	Sodium oxalate	Na2C2O4	Non-hygroscopic. Slightly reacts with magnesium, no reaction with aluminium.
Yellow	Sodium nitrate Sodium nitrate Sodium nitrate is the chemical compound with the formula NaNO3. This salt, also known as Chile saltpeter or Peru saltpeter to distinguish it from ordinary saltpeter, potassium nitrate, is a white solid which is very soluble in water...	NaNO3	Also acts as oxidizer. Bright flame, used for illumination.
Yellow	Cryolite Cryolite Cryolite is an uncommon mineral identified with the once large deposit at Ivigtût on the west coast of Greenland, depleted by 1987....	Na3AlF6	One of the few sodium salts that is nonhygroscopic and insoluble in water.
Green	Barium chloride Barium chloride Barium chloride is the inorganic compound with the formula BaCl2. It is one of the most common water-soluble salts of barium. Like other barium salts, it is toxic and imparts a yellow-green coloration to a flame. It is also hygroscopic....	BaCl2
Green	Barium chlorate Barium chlorate Barium chlorate is a white crystalline solid. It is an irritant, as are all barium compounds. If consumed, barium chlorate can cause nausea, vomiting, and diarrhea. It is used in pyrotechnics to produce a green color...	Ba(ClO3)2	Classic exhibition green with shellac fuel. Sensitive to shock and friction. Oxidizer.
Green	Barium carbonate Barium carbonate Barium carbonate , also known as witherite, is a chemical compound used in rat poison, bricks, ceramic glazes and cement.Witherite crystallizes in the orthorhombic system...	BaCO3	Pretty color when ammonium perchlorate is used as oxidizer.
Green	Barium nitrate Barium nitrate Barium nitrate with chemical formula Ba2 is a salt of barium and the nitrate ion.Barium nitrate exists as a white solid at room temperature. It is soluble in water, and like other soluble barium compounds, is toxic and should be handled with care...	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 Barium oxalate Barium oxalate, a barium salt of oxalic acid, is a white odorless powder sometimes used as a green pyrotechnic colorant generally in specialized pyrotechnic compositions containing magnesium.Though largely stable, it can be reactive with strong acids...	BaC2O4
Blue	Copper(I) chloride Copper(I) chloride Copper chloride, commonly called cuprous chloride, is the lower chloride of copper, with the formula CuCl. The substance is a white solid sparingly soluble in water, but very soluble in concentrated hydrochloric acid...	CuCl	Richest blue flame. Almost insoluble in water.
Blue	Copper(I) oxide Copper(I) oxide Copper oxide or cuprous oxide is the inorganic compound with the formula Cu2O. It is one of the principal oxides of copper. This red-coloured solid is a component of some antifouling paints. The compound can appear either yellow or red, depending on the size of the particles, but both forms...	Cu2O	Lowest cost blue colorant.
Blue	Copper(II) oxide Copper(II) oxide Copper oxide or cupric oxide is the higher oxide of copper. As a mineral, it is known as tenorite.-Chemistry:It is a black solid with an ionic structure which melts above 1200 °C with some loss of oxygen...	CuO	Used with chlorine donors. Excellent in composite stars Pyrotechnic star Pyrotechnic stars are pellets or simply pieces of pyrotechnic composition which may contain metal powders, salts or other compounds that, when ignited, burn a certain colour or exude a spark effect. They are a part of all projectile-type fireworks. The most common is the aerial shell. When... .
Blue	Copper carbonate	CuCO3	Best when used with ammonium perchlorate Ammonium perchlorate Ammonium perchlorate is an inorganic compound with the formula NH4ClO4. It is the salt of perchloric acid and ammonia. It is a powerful oxidizer, which is why its main use is in solid propellants... .
Blue	Basic copper carbonate	CuCO3·Cu(OH)2, 2 CuCO3·Cu(OH)2	Occurs naturally as malachite Malachite Malachite is a copper carbonate mineral, with the formula Cu2CO32. This green-colored mineral crystallizes in the monoclinic crystal system, and most often forms botryoidal, fibrous, or stalagmitic masses. Individual crystals are rare but do occur as slender to acicular prisms...  and azurite Azurite Azurite is a soft, deep blue copper mineral produced by weathering of copper ore deposits. It is also known as Chessylite after the type locality at Chessy-les-Mines near Lyon, France... . 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 Paris Green Paris Green is an inorganic compound more precisely known as copper acetoarsenite. It is a highly toxic emerald-green crystalline powder that has been used as a rodenticide and insecticide, and also as a pigment, despite its toxicity. It is also used as a blue colorant for fireworks...	Cu(CH3COO)2.3Cu(AsO2)2	Copper acetoarsenite, Emerald Green. Toxic. With potassium perchlorate Potassium perchlorate Potassium perchlorate is the inorganic salt with the chemical formula KClO4. Like other perchlorates, this salt is a strong oxidizer and potentially reacts with many organic substances...  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 Copper Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...  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 Rubidium Rubidium is a chemical element with the symbol Rb and atomic number 37. Rubidium is a soft, silvery-white metallic element of the alkali metal group. Its atomic mass is 85.4678. Elemental rubidium is highly reactive, with properties similar to those of other elements in group 1, such as very rapid...  compounds	Rb	rarely used
Silver/White	Aluminium Aluminium Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....  powder	Al
Silver/White	Magnesium Magnesium Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...  powder	Mg
Silver/White	Titanium Titanium Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....  powder	Ti
Silver/White	Antimony (III) sulfide Antimony sulfide Antimony sulfide may refer to either of the following:*Stibnite, Sb2S3*Antimony pentasulfide, Sb2S5...	Sb2S3
Infrared	Caesium nitrate Caesium nitrate Caesium nitrate is a chemical compound with the chemical formula CsNO3. It is used in pyrotechnic compositions, as a colorant and an oxidizer, e.g. in decoys and illumination flares...	CsNO3	two powerful spectral line Spectral line A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from a deficiency or excess of photons in a narrow frequency range, compared with the nearby frequencies.- Types of line spectra :... s at 852.113 nm and 894.347 nm
Infrared	Rubidium nitrate Rubidium nitrate Rubidium nitrate is an inorganic compound with the formula RbNO3. This salt is white and highly soluble in water.-Properties:Rubidium nitrate is a white crystalline powder that is highly soluble in water and very slightly soluble in acetone. In a flame test, RbNO3 gives a mauve/light purple...	RbNO3

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

Radiating species

Despite the wide numbers of metal ion donors, they serve to form only a few atomic and molecular species that are useful as light emitters.

In many cases, chlorine donors have to be added in order to achieve sufficiently deep colors, as the desired emitting molecules have to be generated.

Some color emitters are of atomic nature (e.g. lithium, sodium). Presence of chlorine, and the reaction to monochlorides, may actually impair their color purity or intensity.

At high temperatures, the atoms will ionize. The emission spectra of ions are different than of neutral atoms; the ions may emit in undesired spectral ranges. E.g. Ba⁺ emits in blue wavelengths. Ionization can be suppressed by addition of an easier-to-ionize metal with weak visible emission of its own, e.g. potassium; the potassium atoms then act as electron donors, neutralizing the barium ions.

The color blue is notoriously difficult to produce in fireworks, as the copper

Copper

Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...

 compounds need to be heated at a specific temperature for the optimal shade of blue to be produced. Thus, a deep, rich blue is usually viewed as the mark of an experienced fireworks maker.

Care should be taken to avoid formation of solid particles in the flame zone, whether metal oxides or carbon; incandescent solid particles emit black body radiation that causes "washing out" of the colors. Addition of aluminium raises the flame temperature but also leads to formation of solid incandescent particles of aluminium oxide and molten aluminium. Magnesium has less such effect and is therefore more suitable for colored flames; it is more volatile than aluminium and more likely to be present as vapors than as particulates. Formation of solid particles of magnesium oxide can further be inhibited by presence of carbon monoxide, either by negative oxygen 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 reacts with the magnesium oxide particles to gaseous magnesium and gaseous carbon dioxide.

Colour	Emitter	Wavelengths	Notes
Yellow	Sodium Sodium Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...  (D-line Atomic spectral line In physics, atomic spectral lines are of two types:* An emission line is formed when an electron makes a transition from a particular discrete energy level of an atom, to a lower energy state, emitting a photon of a particular energy and wavelength... )	589 nm	very strong, overpowers other colors, avoid contamination
Orange	Ca Calcium Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust... Cl Chloride The chloride ion is formed when the element chlorine, a halogen, picks up one electron to form an anion Cl−. The salts of hydrochloric acid HCl contain chloride ions and can also be called chlorides. The chloride ion, and its salts such as sodium chloride, are very soluble in water...  (molecular bands)	most intense: 591–599 nm and 603–608 nm, and others
Red	Sr Strontium Strontium is a chemical element with the symbol Sr and the atomic number 38. An alkaline earth metal, strontium is a soft silver-white or yellowish metallic element that is highly reactive chemically. The metal turns yellow when exposed to air. It occurs naturally in the minerals celestine and... Cl (molecular bands)	a: 617–623 nm b: 627–635 nm c: 640–646 nm	The SrCl species tends to be oxidized to less desirable SrO; strontium-containing compositions are therefore usually formulated to be oxygen-deficient.
Red	SrOH Hydroxide Hydroxide is a diatomic anion with chemical formula OH−. It consists of an oxygen and a hydrogen atom held together by a covalent bond, and carrying a negative electric charge. It is an important but usually minor constituent of water. It functions as a base, as a ligand, a nucleophile, and a... (?) (molecular bands)	600–613 nm
Red	Li (atomic spectral lines)
Green	Ba Barium Barium is a chemical element with the symbol Ba and atomic number 56. It is the fifth element in Group 2, a soft silvery metallic alkaline earth metal. Barium is never found in nature in its pure form due to its reactivity with air. Its oxide is historically known as baryta but it reacts with... Cl (molecular bands)	a: 511–515 nm b: 524–528 nm d: 530–533 nm	Lines of BaOH and BaO are also present, emitting in yellow and yellowish-green (487, 512, 740, 828, and 867 nm for BaOH, 549, 564, 604 and 649 for BaO). The BaOH lines are much stronger than the BaO lines. In absence of chlorine, the BaCl lines are not present and only the BaOH and BaO lines are visible. The BaCl species tends to be oxidized to less desirable BaO; barium-containing compositions are therefore usually formulated to be oxygen-deficient. Presence of Ba+ is undesired, as it emits in a blue region at 455.4 nm. Potassium may be added to suppress barium ionization, as it ionizes easier and acts as an electron donor for the barium ions.
Blue	Cu Copper Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish... Cl (molecular bands)	several intense bands between 403–456 nm, less intense at 460–530 nm	Low dissociation energy of copper compounds causes presence of free copper atoms in the flame, weakly emitting in green (lines between 325–522 nm). In presence of chlorine, CuCl is formed, emitting strongly in blue. At higher temperatures CuCl dissociates and lines of atomic copper are present in the spectrum; CuO and CuOH are also formed, emitting molecular bands at green-yellow (535–555 nm) for CuOH and at orange-red (580–655 nm) for CuOH. Adequate control of temperature is therefore required for blue-burning compositions.
Infrared	Carbon Carbon Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...  particles	black body radiation	For good broadband infrared output, compositions producing lots of heat and carbon particles are required. The burning temperature should be lower than of visible-illuminating compounds. The intensity of the emitted radiation depends on the burn rate. Temperature can be increased by addition of magnesium Magnesium Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole... . A magnesium/Teflon/Viton Magnesium/Teflon/Viton Magnesium/Teflon/Viton is a pyrolant. Teflon and Viton are trademarks of DuPont for polytetrafluoroethylene, n, and vinylidenfluoride-hexafluoroisopropene-copolymer, nn.-History:...  composition is common for missile decoy flares Flare (countermeasure) A flare is an aerial infrared countermeasure to counter an infrared homing surface-to-air missile or air-to-air missile. Flares are commonly composed of a pyrotechnic composition based on magnesium or another hot-burning metal, with burning temperature equal to or hotter than engine exhaust... .
Infrared	CO2 Carbon dioxide Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...  (molecular bands)	mostly 4300 nm	Produced by carbon-containing fuels.
Infrared	Cs (atomic spectral lines)	two powerful spectral line Spectral line A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from a deficiency or excess of photons in a narrow frequency range, compared with the nearby frequencies.- Types of line spectra :... s at 852.113 nm and 894.347 nm	Used in infrared illumination compositions. Metal is avoided in the compositions to prevent formation of bright, visible-radiating particles.
Infrared	Rb Rubidium Rubidium is a chemical element with the symbol Rb and atomic number 37. Rubidium is a soft, silvery-white metallic element of the alkali metal group. Its atomic mass is 85.4678. Elemental rubidium is highly reactive, with properties similar to those of other elements in group 1, such as very rapid... (atomic spectral lines)	spectral lines in near-infrared	Used in infrared illumination compositions, less commonly than cesium.