Chrome orange

From Wikipedia, the free encyclopedia

Chrome Orange is a natural orange pigment made of lead(II) chromate and lead(II) oxide. (PbCrO₄ + PbO).

Names for Chrome orange:

        Pronunciation: krome   are • inj  

Alternative names: Derby red, Persian red, Victoria red, Word origin: The name "Chrome orange" comes from Greek khroma = color. Non-English names: German French Italian

Chromorange   chromorange   rosetto chrome  

Chemical name: Basic lead(II)-chromate

When was Chrome orange used?

        Discovery:       Used until:   

1809 The world production of chrome orange ceased few years ago. Now it is an obsolete pigment.

How Chrome orange is made:

        Artificial variety of pigment Precipitation of solutions of lead salts with alkaline chromate or bichromate solutions at high temperature. 

In the lab Materials needed: lead(II) nitrate (Pb(NO3)2), potassium dichromate (K2Cr2O7), sodium hydroxide (NaOH) Safety (MSDSs): Lead(II) nitrate, potassium dichromate, sodium hydroxide (at Fisher Scientific) Method: 6 g Pb(NO3)2 5 g K2Cr2O7 are separately solved in 100 ml deionized water each. Two to three pellets of sodium hydroxide are then added to the dichromate solution and both solution are heated to boiling temperature. The lead nitrate solution is the slowly added into the stirred dichromate solution and the resulting precipitate is filtered off, washed with deionized water and dried.