Chrome orange

  • Basic lead chromate
  • Turkey red
  • Vienna Red
  • Chrome cinnabar
  • Phönikochroit

Red, amorphous or crystalline solid

Fixed

Risk

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Chrome red, PbCrO4, PbO · X, is a basic lead salt of chromic acid and its hydrates ( PbCrO4 · Pb ( OH) x). This has a bright red color and is also Turkey red, Viennese red, chrome and vermilion as mineral Phönikochroit named, but is harmful to health. A variant is chrome orange.

In its properties it closely resembles lead (II) chromate PbCrO4 ( chrome yellow ).

Production

If, for precipitating a lead salt solution ( acetate ) - as for the production of chrome yellow - not sour, but neutral or slightly alkaline chromate, or treated chromate directly with an alkaline solution (eg, sodium hydroxide ), then a red basic lead chromate with the composition PbCrO4 · PbO x (or its hydrates PbCrO4 · Pb ( OH) x).

Orange -colored varieties, called chrome orange, contain lead hydroxides Pb (OH ) 2, and in the manufacture of specially coated so that they are largely stable.

Use

Chrome red was used in oil painting since the beginning of the 19th century. As the related chrome yellow, it is a health hazard and must not be used today.

The stable chromium orange tones are separated still used.

CAS registry number Dangerous Substances Directive (67/548/EEC) Hydration reaction Lead(II) chromate Lead acetate
188710
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