See What Flame Test Colors Look Like (2024)

Updated on August 14, 2019

Sodium, Iron: Yellow

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 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 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

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 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

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 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

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

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

Copper(I): Blue

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

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.