Flame Test Colors: Photo Gallery

Distinctions Can Be Tricky

The flame test is a fun and useful analytical technique to help you identify the chemical composition of a sample based on the way it changes the color of a flame. However, interpreting your results can be tricky if you don't have a reference. There are many shades of green, red, and blue, usually described with color names you wouldn't find on even a large crayon box.

Remember, the color will depend on the fuel you are using for your flame and whether you're viewing the result with the naked eye or through a filter. Describe your result in as much detail as you can. You might want to take pictures with your phone to compare results from other samples. Keep in mind that your results may vary depending on your technique and the purity of your sample. This photo reference of test flame colors is a good place to start, though.

Sodium, Iron: Yellow

Sodium salts burn yellow in the flame test
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Most fuels contain sodium (e.g., candles and wood), so you're familiar with the yellow color this metal adds to a flame. The color is muted when sodium salts are placed in a blue flame, such as a Bunsen burner or alcohol lamp. Be aware, sodium yellow overwhelms other colors. If your sample has any sodium contamination, the color you observe may include an unexpected contribution from yellow. Iron can also produce a golden flame (although sometimes orange).

Calcium: Orange

Calcium carbonate produces an orange flame test color
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Calcium salts produce an orange flame. However, the color may be muted, so it can be hard to distinguish between the yellow of sodium or gold of iron. The usual lab sample is calcium carbonate. If the specimen is not contaminated with sodium, you should get a nice orange color.

Potassium: Purple

Potassium and its compounds burn violet or purple in a flame test

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Potassium salts produce a characteristic purple or violet color in a flame. Assuming your burner flame is blue, it may be difficult to see a big color change. Also, the color may be paler than you expect (more lilac).

Cesium: Purple-Blue

Cesium turns a flame violet in a flame test

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The flame test color you're most likely to confuse with potassium is cesium. Its salts color a flame violet or blue-purple. The good news here is most school labs don't have cesium compounds. Side-by-side, potassium tends to be paler and have a slight pink tint. It may not be possible to tell the two metals apart using only this test.

Lithium, Rubidium: Hot Pink

Lithium salts turn a flame hot pink to magenta

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Lithium yields a flame test somewhere between red and purple. It's possible to get a vivid hot pink color, although more muted colors are also possible. It's less red than strontium (below). It's possible to confuse the result with potassium.

Another element that may produce a similar color is rubidium. For that matter, so can radium, but it's not commonly encountered.

Strontium: Red

Strontium compounds turn a flame red
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The flame test color for strontium is the red of emergency flares and red fireworks. It's a deep crimson to brick red.

Barium, Manganese(II), and Molybdenum: Green

Barium salts produce a yellow-green flame

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Barium salts produce a green flame in the flame test. It's usually described as a yellow-green, apple-green, or lime-green color. The identity of the anion and the concentration of the chemical matter. Sometimes barium produces a yellow flame without noticeable green. Manganese(II) and molybdenum may also yield yellow-green flames.

Copper(II): Green

This is the green flame test result from a copper(II) salt
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Copper colors a flame green, blue, or both depending on its oxidation state. Copper(II) produces a green flame. The compound it's most likely to be confused with is boron, which produces a similar green. (See below.)

Boron: Green

This fire vortex is colored green using a boron salt

ThoughtCo / Anne Helmenstine

Boron colors a flame bright green. It's a common sample for a school lab because borax is readily available.

Copper(I): Blue

This is a blue-green flame test result from a copper compound
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Copper(I) salts produce a blue flame test result. If there is some copper(II) present, you'll get blue-green.

Exclusion Flame Test: Blue

A blue flame test might not tell you which element is present, but at least you know which ones to exclude
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Blue is tricky because it's the usual color of a methanol or burner flame. Other elements that can impart a blue color to a flame test are zinc, selenium, antimony, arsenic, lead, and indium. Plus, there are a host of elements that don't change the color of a flame. If the flame test result is blue, you won't get much information, except you can exclude some elements.

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Helmenstine, Anne Marie, Ph.D. "Flame Test Colors: Photo Gallery." ThoughtCo, Feb. 16, 2021, thoughtco.com/flame-test-colors-photo-gallery-4053133. Helmenstine, Anne Marie, Ph.D. (2021, February 16). Flame Test Colors: Photo Gallery. Retrieved from https://www.thoughtco.com/flame-test-colors-photo-gallery-4053133 Helmenstine, Anne Marie, Ph.D. "Flame Test Colors: Photo Gallery." ThoughtCo. https://www.thoughtco.com/flame-test-colors-photo-gallery-4053133 (accessed June 4, 2023).