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Names | |
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Other names ammonium manganese(III) pyrophosphate | |
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3D model (JSmol) | |
ChemSpider | |
ECHA InfoCard | 100.030.221 |
EC Number |
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PubChem CID | |
UNII | |
CompTox Dashboard (EPA) | |
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Properties | |
NH4MnP2O7 | |
Molar mass | 246.885 |
Appearance | violet solid |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Manganese violet is the inorganic compound with the formula NH4MnP2O7. [1] As implied by its name and composition, it is a purple, inorganic pigment. [2] Because it is often impure, the pigment's hue is varied. [3] Notable artists who have used the pigment include Claude Monet, who relied on manganese violet in his Rouen Cathedral series to further his exploration of shadows. [4] Beyond the artistic community, manganese violet has been used in cosmetics to color products like lipstick and eyeshadow. [5]
The pigment was originally named Nurnberg violet, and little is known about its early history beyond its creation in 1866 by E. Leykeuf. The first documented production of the pigment was in 1890 by Messers Winsor and Newton (currently known as Winsor & Newton). [6] : 128–29 In the Winsor & Newton 1892 catalog, both permanent violet and permanent mauve were listed. The two were distinguished by the company in 1896 when permanent mauve was described as phosphate of Manganese (which is another name for manganese violet). [7] : 257 In 1898, the paint supplier Reeves listed permanent violet and permanent mauve as the same color. [7] : 257
The compound can be generated by combining manganese dioxide, phosphoric acid, and ammonium dihydrogenphosphate. [2] [8] [9] For the synthesis from Mn(III) oxide, an idealized equation follows:
The pigment has two polymorphs: α- and β-forms. Both are stable to about 340 °C. [10] The optical properties of manganese violet arise from the distorted octahedral sites. [10] The infrared spectroscopy, reflectance spectrum, and fluorescence spectroscopy can be found on ColourLex. [11]
According the X-ray crystallography, both polymorphs of manganese violet have similar structures. The feature octahedral Mn(III) centers, which are distorted by Jahn-Teller effect, as expected for a high spin (quintet state) d4 ions. [10]
Manganese violet is a fine, vibrant purple pigment that is synthetically generated. [12] It exhibits exceptional permanence and high lightfastness. [13] [14]
Some artists historically avoided manganese violet because of they found its color to be dull. [6] : 128 Variances in visual characteristics can arise from impurities. [3] : 178 The visual characteristics of manganese violet remain a source of contention among the artistic community. Some sources claim that manganese violet is actually a more accurate violet hue than previous pigments like cobalt violet, which has a redder tone. [12] Conversely, some sources assert that manganese violet (as well as cobalt violet) should not be categorized as violet according to modern color measurements. [15]
The manganese violet pigment is compatible with many artistic techniques; however, it is incompatible with fresco and stereochromy. [13] The pigments' popularity was short lived within the artistic community because of its dullness and poor hiding power. [6]
A number of nineteenth-century artists used the pigment when representing shadows. In Édouard Manet's The Waitress, manganese violet was used to create the red or purple colors. [16] Claude Monet was an avid proponent of manganese violet's usage for shadows. Monet was quoted saying "I have finally discovered the true color of the atmosphere. It's violet. Fresh air is violet. Three years from now, everyone will work in violet." [4] Impressionists used violet in place of black, which they argued was not found in nature. [4] In Monet's Rouen Cathedral series, he utilized diverse colors to display how the perception of the same cathedral changes based on the lighting during the course of the day. In The Rouen Cathedral, West Facade, Sunlight and The Portal of Rouen Cathedral in the Morning Light, Monet manipulated the shadows through using manganese violet and other pigments to represent the time of the day. [4]
Georges Seurat also employed manganese violet in his paintings, though he used it sparingly because he saw it as impure. [17] He tended to use what he regarded as pure pigments, such as cobalt blue, French ultramarine, and lead white. [18] For many of his works, Seurat would combine other pure pigments to create a violet hue and, consequently, he would only utilize impure pigments like manganese violet for specific purposes. [16] In Seurat's painting Channel of Gravelines, Grand Fort-Philippe, for example, manganese violet was used in the border. [18] There is speculation that Seurat utilized manganese violet in the border because of its low tinting power. In comparison to manganese violet, pure pigments and their mixtures have high tinting powers, which may have been undesirable in this case; therefore, Seurat opted to use manganese violet for this painting. [18]
Beyond the artistic community, manganese violet is used various cosmetics such as lipstick and eye products. [5] The United States categorizes it as a safe compound for products used around the eyes such as eyeshadow. [19] Additionally, the pigment is often used in lipstick to counter brighter pigments. [5] Health concerns have been raised about manganese violet and other metal pigments in cosmetics. [20]
Blue is one of the three primary colours in the RYB colour model, as well as in the RGB (additive) colour model. It lies between violet and cyan on the spectrum of visible light. The term blue generally describes colours perceived by humans observing light with a dominant wavelength that’s between approximately 450 and 495 nanometres. Most blues contain a slight mixture of other colours; azure contains some green, while ultramarine contains some violet. The clear daytime sky and the deep sea appear blue because of an optical effect known as Rayleigh scattering. An optical effect called the Tyndall effect explains blue eyes. Distant objects appear more blue because of another optical effect called aerial perspective.
Violet is the color of light at the short wavelength end of the visible spectrum. It is one of the seven colors that Isaac Newton labeled when dividing the spectrum of visible light in 1672. Violet light has a wavelength between approximately 380 and 435 nanometers. The color's name is derived from the Viola genus of flowers.
Purple is a color similar in appearance to violet light. In the RYB color model historically used in the arts, purple is a secondary color created by combining red and blue pigments. In the CMYK color model used in modern printing, purple is made by combining magenta pigment with either cyan pigment, black pigment, or both. In the RGB color model used in computer and television screens, purple is created by mixing red and blue light in order to create colors that appear similar to violet light.
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Neo-Impressionism is a term coined by French art critic Félix Fénéon in 1886 to describe an art movement founded by Georges Seurat. Seurat's most renowned masterpiece, A Sunday Afternoon on the Island of La Grande Jatte, marked the beginning of this movement when it first made its appearance at an exhibition of the Société des Artistes Indépendants in Paris. Around this time, the peak of France's modern era emerged and many painters were in search of new methods. Followers of Neo-Impressionism, in particular, were drawn to modern urban scenes as well as landscapes and seashores. Science-based interpretation of lines and colors influenced Neo-Impressionists' characterization of their own contemporary art. The Pointillist and Divisionist techniques are often mentioned in this context, because they were the dominant techniques in the beginning of the Neo-Impressionist movement.
Cerulean, also spelled caerulean, is a variety of the hue of blue that may range from a light azure blue to a more intense sky blue, and may be mixed as well with the hue of green. The first recorded use of cerulean as a colour name in English was in 1590. The word is derived from the Latin word caeruleus, "dark blue, blue, or blue-green", which in turn probably derives from caerulum, diminutive of caelum, "heaven, sky".
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Violet is a color term derived from the flower of the same name. There are numerous variations of the color violet, a sampling of which are shown below.
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YInMn Blue, also known as Oregon Blue or Mas Blue, is an inorganic blue pigment that was discovered by Mas Subramanian and his (then) graduate student, Andrew Smith, at Oregon State University in 2009. The pigment is noteworthy for its vibrant, near-perfect blue color and unusually high NIR reflectance. The chemical compound has a unique crystal structure in which trivalent manganese ions in the trigonal bipyramidal coordination are responsible for the observed intense blue color. Since the initial discovery, the fundamental principles of colour science have been explored extensively by the Subramanian research team at Oregon State University, resulting in a wide range of rationally designed novel green, purple, and orange pigments, all through intentional addition of a chromophore in the trigonal bipyramidal coordination environment.
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