Chrome orange
| Names | |
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Other names
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| Identifiers | |
3D model (JSmol)
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| ChemSpider | |
| ECHA InfoCard | 100.038.476 |
| EC Number |
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PubChem CID
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CompTox Dashboard (EPA)
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| Properties[1] | |
| CrO5Pb2 | |
| Molar mass | 546.4 g·mol−1 |
| Appearance | red solid |
| Density | 6.63 g/cm3 |
| Melting point | 920 °C (1,690 °F; 1,190 K) |
| insoluble | |
| Solubility | soluble in acids, alkalis |
| Structure[2] | |
| monoclinic | |
| c2/m | |
a = 14.018 Å, b = 5.683 Å, c = 7.143 Å α = 90°, β = 115.23°, γ = 90°
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Lattice volume (V)
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514.8 Å3 |
Formula units (Z)
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4 units per cell |
| Thermochemistry[3] | |
Gibbs free energy (ΔfG⦵)
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-1161.3 kJ/mol |
| Hazards | |
| GHS labelling:[1] | |
| Danger | |
| H302, H332, H360, H373, H410 | |
| P203, P260, P264, P270, P271, P273, P280, P301+P317, P304+P340, P317, P318, P319, P330, P391, P405, P501 | |
Threshold limit value (TLV)
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0.0002 mg/m3, 0.0005 mg/m3 (STEL) |
| NIOSH (US health exposure limits):[1] | |
IDLH (Immediate danger)
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100.0 mg/m3 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references
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Chrome orange is a mixed oxide with the chemical formula Pb2CrO5. It has found use as a pigment.
Properties
Visible light activity up to 550 nanometers has been recorded.[4]
Synthesis
Pb2CrO5 can be made by treating a lead(II) salt with an alkaline solution of a chromate or by treating chrome yellow (PbCrO4) with strongly basic solution.[5]
It can also be synthesized using a gas-liquid precipitation process.[6] Changing the pH controls whether PbCrO4 or Pb2CrO5 is created.[6]
Nanomaterial
Orthorhombic nanocrystals can be selectively synthesized by a room temperature solution reaction.[7]
Using a microwave-assisted ionic liquid (MAIL) method, bundle and rod-like nanocrystals of Pb2CrO5 are formed.[8] In basic solution, single-crystalline Pb2CrO5 could be formed by heating lead acetate and potassium dichromate with microwave radiation for only 10 minutes at 90 °C.[8] The MAIL process is simple, fast, and does not employ surfactants.[8] The presence of hydroxide changes the phase that is formed. Using NaOH, monoclinic Pb2CrO5 is formed.[8] The bundle and rod-shaped structures are sensitive to electron beam irradiation, which will turn them into many small particles.[8]
Pigment
In a catalog published c. 1835, Winsor and Newton paint company identify ten synthetic pathways for producing chrome orange, also called deep yellow.[9] Chrome orange is made of PbCrO4 mixed with basic lead chromate (Pb2CrO5).[9] It has been described as a "yellowish red or sometimes a beautiful deep red" in alkaline conditions.[9] A deep yellow can be created using PbCrO4 and lead sulfate.[9] There are ten synthetic methods for preparing deep chrome yellow (that made with Pb2CrO5), which require a chromate source, a basic lead source, additives, and a sulfate source.[9] Controlling the pH was Winsor and Newton's method for creating pigments from the pale yellow to the deep chrome orange.[9] The resulting product has a high stability to light, which is always coveted by artists and collectors.[9]
Use as a pigment
| Chrome Orange | |
|---|---|
| Color coordinates | |
| Hex triplet | #E73501 |
| sRGBB (r, g, b) | (231, 53, 1) |
| HSV (h, s, v) | (14°, 100%, 91%) |
| CIELChuv (L, C, h) | (51, 147, 16°) |
| Source | ColourLex[11] |
| B: Normalized to [0–255] (byte) | |
Chrome orange can range in color from light to deep orange and is no longer in production as a pigment.[12] It has also been known as Derby red, Persian red, and Victoria red.[12] It was first recorded as a pigment in 1809 and was perfect for some impressionist painters in the nineteenth century. The yellow-orange pigment of the boat in Renoir's 1879 painting, The Seine at Asnières (The Skiff) at the National Gallery, London.[12] Chrome orange was used extensively in Frederic Leighton's Flaming June (1895; Museo de Arte de Ponce).[10]
History
The natural mineral crocoite was discovered in 1797 by Louis Vauquelin and chrome orange was synthesized as a pigment for the first time in 1809.[12] Pb2CrO5 is found in mineral form as phoenicochroite, which is a monoclinic, red, translucent mineral found in various places across the world, including Russia, the US, and Chile.[13]
See also
References
- ^ a b c PubChem. "Lead chromate oxide". pubchem.ncbi.nlm.nih.gov. Retrieved 2026-02-11.
- ^ Morita, Shinichi; Toda, Kohji (1984-04-01). "Determination of the crystal structure of Pb2CrO5". Journal of Applied Physics. 55 (7): 2733–2737. doi:10.1063/1.333271. ISSN 0021-8979.
- ^ Sahu, Sulata Kumari; Ganesan, Rajesh; Gnanasekaran, T. (2010-01-01). "Standard molar Gibbs free energy of formation of Pb5CrO8(s), Pb2CrO5(s), and PbCrO4(s)". The Journal of Chemical Thermodynamics. 42 (1): 1–7. doi:10.1016/j.jct.2009.06.026. ISSN 0021-9614. S2CID 55549520.
- ^ Lee, Heung Chan; Cho, Sung Ki; Park, Hyun S.; Nam, Ki Min; Bard, Allen J. (2017-08-24). "Visible Light Photoelectrochemical Properties of PbCrO 4, Pb 2 CrO 5, and Pb 5 CrO 8". The Journal of Physical Chemistry C. 121 (33): 17561–17568. doi:10.1021/acs.jpcc.7b03230. ISSN 1932-7447.
- ^ Völz, Hans G.; et al. (2006). "Pigments, Inorganic". Ullmann's Encyclopedia of Industrial Chemistry. Wiley-VCH. doi:10.1002/14356007.a20_243.pub2. ISBN 3527306730..
- ^ a b Gu, LiNa; Meng, GuangYao (2007-09-05). "Synthesis and characterization of two PbO-chromium oxides". Powder Technology. 178 (1): 1–4. doi:10.1016/j.powtec.2007.01.017. ISSN 0032-5910.
- ^ Ma, Ming-Guo; Zhu, Ying-Jie; Li, Shu-Hong (2009-02-04). "A simple route to the synthesis of BaCrO4 microstructures at room temperature". Materials Research Bulletin. 44 (2): 288–293. doi:10.1016/j.materresbull.2008.06.003. ISSN 0025-5408.
- ^ a b c d e Wang, Wei-Wei; Zhu, Ying-Jie (2005-03-01). "Synthesis of PbCrO 4 and Pb 2 CrO 5 Rods via a Microwave-Assisted Ionic Liquid Method". Crystal Growth & Design. 5 (2): 505–507. doi:10.1021/cg0497546. ISSN 1528-7483.
- ^ a b c d e f g Otero, Vanessa; Pinto, Joana V.; Carlyle, Leslie; Vilarigues, Márcia; Cotte, Marine; João Melo, Maria (2017). "Nineteenth Century Chrome Yellow and Chrome Deep from Winsor & Newton". Studies in Conservation. 62 (3): 123–149. doi:10.1080/00393630.2015.1131478. S2CID 138176187.
- ^ a b Color in the Making. London: Black Dog Publishing. 2013. p. 104. ISBN 9781907317958.
- ^ "Chrome orange – ColourLex". ColourLex. Retrieved 22 December 2022.
- ^ a b c d "Pigments through the Ages – Overview – Chrome orange". webexhibits.org. Retrieved 2022-05-11.
- ^ "Phoenicochroite". mindat.org. Retrieved 2022-05-11.
Further reading
- Kühn, H. and Curran, M., "Chrome Yellow and Other Chromate Pigments", in Artists' Pigments. A Handbook of Their History and Characteristics, Vol. 1, L. Feller, Ed., Cambridge University Press, London 1986, pp. 208–211.
- Chrome Orange at ColourLex