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 fireworks. Some common examples are:
| Colour | Compound name | Chemical formula | Notes |
|---|---|---|---|
| Red | Strontium nitrate | SrNO3 | 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. Fire retardant in gunpowders. Inexpensive, non-hygroscopic, neutralizes acids. |
| Red | Strontium sulfate | SrSO4 | High-temperature oxidizer. Used in strobe mixtures and some metal-based red compositions. |
| 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 [[carbon]oxygen based carbon OC12] | Fe+C | |
| Gold/Yellow | Sodium nitrate | NaNO3 | |
| Gold/Yellow | Cryolite | Na3AlF6 | One of few sodium salts that is nonhygroscopic and insoluble in water. |
| Green | Barium chloride | BaCl2 | |
| Green | Barium chlorate | BaClO3 | Sensitive to shock and friction. Oxidizer. |
| Green | Barium carbonate | BaCO3 | |
| 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 | |
| Blue | Copper(II) oxide | CuO | Used with chlorine donors. Excellent in composite stars. |
| Blue | Copper carbonate | CuCO3 | Best when used with ammonium perchlorate. |
| Blue | Copper oxychloride | 3CuO.CuCl2 | Used in cheap compositions. Not common anymore due to need for mercury(II) chloride to bring out the color. |
| Blue | Paris Green | Cu(C2H3O2)2.3Cu(AsO2)2 | Toxic. With potassium perchlorate produces the best blue colors. |
| Blue | Copper metal | Cu | Rarely used, other compounds are easier to work with. |
| 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.
The color blue is notoriously difficult to produce in fireworks, as the copper 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.
In many cases, chlorine donors have to be added in order to achieve sufficiently deep colors.
Care should be taken to avoid formation of solid particles, whether metal oxides or carbon; incandescent solid particles emit black body radiation that causes "washing out" of the colors.
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:
| Colour | Emitter | Wavelengths | Notes |
|---|---|---|---|
| Yellow | Sodium (D-line) | 589 nm | very strong, overpowers other colors, avoid contamination |
| Orange | CaCl (molecular bands) | most intense: 591-599 nm and 603-608 nm, and others | |
| Red | SrCl (molecular bands) | a: 617-623 nm b: 627-635 nm c: 640-646 nm |
|
| Red | SrOH(?) (molecular bands) | 600-613 nm | |
| Green | BaCl (molecular bands) | a: 511-515 nm b: 524-528 nm d: 530-533 nm |
Lines of BaOH and BaO often present, emitting in yellow and yellowish-green |
| Blue | CuCl (molecular bands) | several intense bands between 403-456 nm, less intense at 460-530 nm |
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