Chrome red

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Structural formula
Lead coatingChromatanion.svgPointXBracket openLead coatingOxygen anionBracket to
General
Surname Chrome red
other names
Molecular formula PbCrO 4 · x PbO or PbCrO 4 · Pb (OH) x
Brief description

red, amorphous or crystalline solid

External identifiers / databases
CAS number 18454-12-1
EC number 242-339-9
ECHA InfoCard 100.038.476
Wikidata Q424012
properties
Molar mass 546.4 g / mol (x = 1)
Physical state

firmly

safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary
08 - Dangerous to health 09 - Dangerous for the environment

danger

H and P phrases H: 350-360Df-373-410
P: ?
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Chrome red , PbCrO 4 · x PbO, is a basic lead salt of chromic acid or its hydrates (PbCrO 4 · Pb (OH) x ). This has a bright red color and is also known as Turkish red, Viennese red, chrome cinnabar and, as a mineral, Phoenicochroit , but is harmful to health. One variant is chrome orange .

Its properties are very similar to the lead (II) chromate PbCrO 4 (chrome yellow).

Manufacturing

If you use neutral or weakly alkaline chromate solutions to precipitate a lead salt solution ( lead acetate ) - as is the case for the production of chrome yellow - or if lead chromate is treated directly with an alkaline solution (e.g. sodium hydroxide solution ), a red basic lead chromate is formed with the Composition PbCrO 4 · x PbO (or its hydrates PbCrO 4 · Pb (OH) x ).

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

Chrome orange

use

Chrome red has been used in oil painting since the early 19th century. Like the related chrome yellow , it is harmful to health and may no longer be used today.

The more stable chrome orange tones are still used occasionally.

In contrast to chrome yellow, chrome red and most of the chrome orange tones are lime-fast.

Individual evidence

  1. ↑ a b Dr. A. Eibner: Painting materials as the basis of the painting technique. For art students, artists, painters, varnishers, manufacturers and dealers , 1909, Julius Springer Verlag, Berlin
  2. ^ Richard J. Lewis Sr .: Hazardous chemicals desk reference . 6th edition. John Wiley & Sons, Hoboken, New Jersey, USA 2008, ISBN 978-0-470-18024-2 , pp. 825 ( limited preview in Google Book search).
  3. ↑ entry to Bleichromatoxid in GESTIS Bank of IFA , accessed on 23 July 2016(JavaScript required) .
  4. ↑ Not explicitly listed in Regulation (EC) No. 1272/2008 (CLP) , but with the specified labeling it falls under the group entries on Chromium (VI) compounds, with the exception of barium chromate and of compounds specified elsewhere in this Annex and lead compounds with the exception of those specified elsewhere in this Annex in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on March 18, 2017. Manufacturers or distributors can expand the harmonized classification and labeling .
  5. ↑ Chromium pigments index card in Materialarchiv.ch
  6. ↑ Description of chrome yellow ( Memento of the original from March 8, 2017 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. at Kremer Pigments @1@ 2Template: Webachiv / IABot / kremerfarben.de