Flame test

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A flame test is an analytical procedure that can determine the presence of certain elements.

Procedure

A flame test is carried out by placing a sample on a clean wire (commonly made out of platinum or nichrome), and placing it in a hot non-luminous flame (one that does not exhibit black-body radiation).

Flame colors

Azure

  • Copper halides (copper(II) chloride)
  • Bismuth

Bluish-green

  • Phosphates with sulfuric acid
  • Phosphorus
  • Zinc metal

Brick red

  • Cadmium

Carmine

  • Lithium (violet through blue glass, invisible through green glass, masked by barium)

Crimson red

  • Radium

Emerald

  • Copper non-halides
  • Ytterbium metal powder

Feeble green

  • Ammonium
  • Antimony

Gray

Light blue

  • Arsenic
  • Cesium
  • Lead
  • Selenium

Orange

  • Calcium (greenish through blue glass, green through green glass, masked by barium)
  • Scandium

Pale blue

  • Germanium

Pale green

  • Antimony

Pink

  • Samarium metal

Pure green

  • Boron
  • Tellurium
  • Thallium

Purple

  • Potassium chloride

Red

  • Mercury

Red-violet

  • Rubidium

Scarlet

  • Strontium (violet through blue glass, yellowish through green glass, masked by barium)

Silvery-white

  • Aluminium
  • Chromium
  • Cobalt
  • Nickel

Violet

  • Potassium (masked easily)

White

  • Beryllium
  • Magnesium

Yellow

  • Sodium (masks everything, invisible through blue glass)

Yellowish-green

  • Barium
  • Manganese
  • Molybdenum
  • Vanadium

Spectroscopy

A mad scientist with a more technical bent can improve this technique by building a simple spectroscope, which decomposes the light from the flame into a spectrum. The advantages of spectroscopy is that it does not require any colored glass, all spectral lines are visible separately without them.

References

Relevant Sciencemadness threads