Chrome orange
Encyclopedia
Chrome orange, also known as chrome red, is an orange
pigment
which consists of lead(II) chromate
and lead(II) oxide
. (PbCrO4 and PbO). Chrome orange can be made by precipitating lead(II) together with chromate in a basic solution or by treating chrome yellow
with lye
. It is toxic both from the contained lead and from the contained hexavalent chromium
.
It was used in the past as a pigment in paints, but is now restricted or illegal because of the drive to reduce or remove lead and its compounds from paints.
Orange (colour)
The colour orange occurs between red and yellow in the visible spectrum at a wavelength of about 585–620 nm, and has a hue of 30° in HSV colour space. It is numerically halfway between red and yellow in a gamma-compressed RGB colour space, the expression of which is the RGB colour wheel. The...
pigment
Pigment
A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light.Many materials selectively absorb...
which consists of lead(II) chromate
Lead(II) chromate
Lead chromate is a chemical compound, a chromate of lead. It has a vivid yellow color and is practically insoluble in water, and as a result, is used in paints under the name "chrome yellow"...
and lead(II) oxide
Lead(II) oxide
Lead oxide is the inorganic compound with the formula PbO. Lead oxide occurs in two polymorphs, red, having a tetragonal crystal structure and yellow, having an orthorhombic crystal structure...
. (PbCrO4 and PbO). Chrome orange can be made by precipitating lead(II) together with chromate in a basic solution or by treating chrome yellow
Chrome yellow
Chrome Yellow is a natural yellow pigment made of lead chromate . It was first extracted from the mineral crocoite by the French chemist Louis Vauquelin in 1809...
with lye
Lye
Lye is a corrosive alkaline substance, commonly sodium hydroxide or historically potassium hydroxide . Previously, lye was among the many different alkalis leached from hardwood ashes...
. It is toxic both from the contained lead and from the contained hexavalent chromium
Hexavalent chromium
Hexavalent chromium refers to chemical compounds that contain the element chromium in the +6 oxidation state. Virtually all chromium ore is processed via hexavalent chromium, specifically the salt sodium dichromate. Approximately of hexavalent chromium were produced in 1985...
.
It was used in the past as a pigment in paints, but is now restricted or illegal because of the drive to reduce or remove lead and its compounds from paints.