This page defines how to do a fire test for a selection of steel ions, and also briefly discusses just how the flame color arises. Fire tests are used to recognize the visibility of a fairly small number of metal ion in a compound. Not all metal ions offer flame colors. For team 1 compounds, flame tests are usually by much the easiest means of identifying which steel you have got. For other metals, there room usually other easy methods that are much more reliable - however the flame check can give a valuable hint regarding where come look.

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Figure (PageIndex1): colored flames native strontium, cesium, sodium and also lithium (from left come right). Snapshot courtesy that the Claire Murray and also Annabelle Baker from the Diamond light Source. Check the colors with the facets on Table (PageIndex1).

Practical Details in transferring out fire Tests

Clean a platinum or nichrome (a nickel-chromium alloy) cable by dipping it into concentrated hydrochloric acid and also then holding it in a hot Bunsen flame. Repeat this until the cable produces no color in the flame. As soon as the wire is clean, moisten the again in the acid and also then dip it right into a tiny amount that the solid to be tested so that part sticks to the wire. Location the wire back in the flame. If the flame shade is weak, it is often beneficial to dive the wire earlier in the acid and also put it earlier into the flame together if clean it. This should produce a an extremely short yet intense speed of color.

There will, in fact, constantly be a map of orange in the fire if you usage nichrome. Platinum is much much better to use but is much, much an ext expensive. If you have a an especially dirty little of nichrome wire, you deserve to just chop the finish off. You do not carry out that v platinum! Dilute hydrochloric acid can be used instead of focused acid for safety and security reasons, yet does not constantly give such extreme flame colors.

The colour in Table (PageIndex1) are simply a guide. Virtually everybody sees and also describes colour differently. Ns have, because that example, used the native "red" several times to define colors that deserve to be quite various from each other. Other world use words favor "carmine" or "crimson" or "scarlet", however not everyone knows the differences between these indigenous - specifically if their first language is no English.

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Table (PageIndex1): fire colors the common elements Elementflame color
Lithium red
Sodium strong, persistent orange
Potassium lilac (pink)
Rubidium red (red-violet)
Cesium blue/violet (see below)
Calcium orange-red
Strontium red
Barium pale green
Copper blue-green (often through white flashes)
Lead gray-white

What do you do if you have actually a red flame shade for an unknown compound and do not recognize which that the assorted reds it is? get samples of known lithium, strontium (etc) compounds and also repeat the fire test, compare the colors produced by one of the recognized compounds and the unknown link side through side till you have actually a good match.