Yellow
Cryolite and sodium nitrate work together to give explosions their yellow color. Sodium nitrate serves as both a yellow colorant and an oxidizer in pyrotechnics, creating a yellow flame. In contrast, cryolite is a common yellow pigment used in fireworks. The pyrotechnics' yellow hue is caused by the extra energy released by these substances when they ignite. Photons have various wavelengths in the visible range. Furthermore, it is well known that compounds containing sodium glow yellow in a flame. The metal cation mostly determines the flame's color, with the salt anion having very little direct effect. Therefore, the combination of sodium nitrate and cryolite leads to the production of the yellow color in fireworks.
Gold
Iron (Fe) combined with soot or charcoal does not give fireworks their golden hue. Fireworks that contain sodium have a yellow or gold tint. Sparks are created by iron, and the color of the sparks is determined by the metal's heat. On the other hand, there are a lot of blue lines and a few green lines in the Fe emission spectrum. Iron may not be employed as a pyro colorant because black-body radiation would outweigh any iron emissions in an arc-welding scenario.
When metal salts and explosives in fireworks react chemically with oxygen, smoke and gases like nitrogen, carbon dioxide, and carbon monoxide are released. These gases are some of the main greenhouse gases that cause climate change. These metal salts do not "burn up" in the explosion. Even yet, they remain metal atoms, and a large number of them become aerosols that contaminate the land, water, and air.
White
As summarized by Thought Co, Barium oxide and white metals like aluminum, titanium, and magnesium are used to make white fireworks because they burn brilliantly and raise the firework's temperature. The photon's energy defines its color or wavelength. The salts required to create the appropriate hue can occasionally be unstable. Since room temperature barium chloride (green) is unstable, barium needs to be mixed with a more stable substance (like chlorinated rubber). In this instance, the heat from burning the pyrotechnic mixture releases chlorine, which subsequently forms barium chloride and gives the scene its green hue. Three minerals are utilized to make gray and white fireworks: magnesium, zirconium, and titanium.
Silver
Fireworks get their silver hue by burning aluminum and magnesium. Magnesium burns to produce a bright white light that is utilized to enhance a fireworks display's overall brilliance or add white sparkles. In contrast, aluminum is utilized to create sparks and flames that are silver and white. Fireworks have a striking silver hue because of the extreme heat that causes the aluminum particles to react with the oxygen in the air, releasing a considerable quantity of energy in the form of heat and light. Hence, the silver hue of pyrotechnics is caused by the burning of magnesium and aluminum together.
Blue
Blue fireworks are a rare color. Think about it, have you ever seen blue fireworks? Because the blue color of fireworks derived from copper chloride is very difficult to make. In addition, the color is not very visible in the night sky. So, blue is often avoided for the color of the fireworks flame.
