Wiktionary
n. (context chemistry English) A potassium salt of chromic acid, K2Cr2O7; the orange crystals are soluble in water, and it is used as an oxidizing agent and in photography.
WordNet
n. an orange-red salt used in making dyes and in photography
Wikipedia
Potassium dichromate, KCrO, is a common inorganic chemical reagent, most commonly used as an oxidizing agent in various laboratory and industrial applications. As with all hexavalent chromium compounds, it is acutely and chronically harmful to health. It is a crystalline ionic solid with a very bright, red-orange color. The salt is popular in the laboratory because it is not deliquescent, in contrast to the more industrially relevant salt sodium dichromate.
Usage examples of "potassium dichromate".
He indicated a second atomizer, added, for effect, that, This test is something like the original one of dissolving strychnine in sulphuric acid, which causes no change, but, on the addition of a bit of potassium dichromate, tints variously blue, violet, and even red are produced.