YInMn Blue (/jɪnmɪn/; for the chemical symbols Y for yttrium, In for indium, and Mn for manganese), also known as Oregon Blue or Mas Blue, is an inorganicblue pigment that was discovered by Mas Subramanian and his (then) graduate student, Andrew Smith, at Oregon State University in 2009.[1][3] The pigment is noteworthy for its vibrant, near-perfect bluecolor and unusually high NIR reflectance.[2] The chemical compound has a unique crystal structure in which trivalentmanganese 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.[4][5]
Historical pigments
The discovery of the first known synthetic blue pigment, Egyptian blue (CaCuSi4O10) was promoted by the Egyptianpharaohs who sponsored the creation of new pigments to be used in art.[6] Other civilizations combined organic and mineral materials to create blue pigments ranging from azure-blue like the Maya blue[1] to the Han blue (BaCuSi4O10), which was developed by the ChineseHan dynasty and manipulated to produce a light or dark blue color.[7]
Most known pigments have detrimental health and environmental effects and/or durability issues. Cobalt blue causes cobalt poisoning when inhaled or ingested.[15] Prussian blue is known to liberate hydrogen cyanide under certain acidic conditions.[16] Ultramarine and azurite are not stable particularly in high-temperature and acidic conditions; additionally, ultramarine production involves the emission of a large amount of the toxic sulfur dioxide.[1] The newer Phthalocyanine Blue BN is non-biodegradable and has been found to cause neuroanatomical defects in developing chicken embryos when injected directly into incubating eggs.[17][18]
Inorganic blue pigments in which manganese (in the pentavalent oxidation state and in a tetrahedral coordination) is the chromophore have been employed since the Middle Ages (e.g., the fossil bone odontolite, which is isostructural to the apatite structure).[19][20] Synthetic alternatives, such as barium manganate sulfate (or Manganese Blue, developed in 1907 and patented in 1935), have been phased out industrially due to safety and regulatory concerns,[21][22] hence YInMn Blue fills the niche of an inorganic, environmentally safe alternative to the traditionally used blue pigments, and offers a durable intense blue color.[1]
Discovery
In 2008, Mas Subramanian received a National Science Foundation grant to explore novel materials for electronics applications. Under this project, he was particularly interested in synthesizing multiferroics based on manganese oxides. He guided Andrew E. Smith, the first graduate student in his lab, to research an oxide solid solution between YInO3 (a ferroelectric material) and YMnO3 (an antiferromagnetic material) at 1,093 °C (2,000 °F). The resulting compound Smith synthesized was by coincidence a vibrant blue material. Because of Subramanian's experience at DuPont, he recognized the compound's potential use as a blue pigment and together they filed a patent disclosure covering the invention. After publishing their results, Shepherd Color Company successfully contacted Subramanian for possible collaboration in commercialization efforts.[23][24] For his outstanding contributions to inorganic color pigment chemistry, Subramanian was awarded the Perkin Medal from the Society of Dyers and Colourists in 2019.[25]
The pigment is noteworthy for its vibrant, near-perfect bluecolor and unusually high NIR reflectance.[1][2] The color may be adjusted by varying the In/Mn ratio in the pigment's base formula of YIn1−xMnxO3, but the bluest pigment, YIn0.8Mn0.2O3, has a color comparable to standard cobalt blueCoAl2O4 pigments.[2]
Properties and preparation
YInMn Blue is chemically stable, does not fade, and is non-toxic. It is more durable than alternative blue pigments such as ultramarine or Prussian blue, retaining its vibrant color in oil and water, and is safer than cobalt blue, which is a suspected carcinogen and may cause cobalt poisoning.[26]
The pigment is resistant to acids such as nitric acid, and is difficult to combust. When YInMn Blue does ignite, it burns a violet color attributed to the indium atoms.[27]
Infrared radiation is strongly reflected by YInMn Blue, which makes this pigment suitable for energy-saving, cool coatings.[28] It can be prepared by heating the oxides of the elements yttrium, indium, and manganese to a temperature of approximately 1,200 °C (2,200 °F).[29]
Commercialization
In popular culture
After Subramanian, Smith, and other colleagues published their results, companies began inquiring about commercial uses. Shepherd Color Company eventually won the license to commercialize the pigment in May 2015.[23][24][28][30] Many companies such as AMD and Crayola rushed to use the new pigment name in product announcements and press releases. It is unclear when the first commercial application of YInMn blue reached the consumer market.
AMD announced in July 2016 that the pigment would be used on new Radeon Pro WX and Pro SSG professional GPUs for the energy efficiency that stems from its near-infrared reflecting property.[31][32]
The American art supplies company Crayola announced in May 2017 that it planned to replace its retired Dandelion color (a yellow) with a new color "inspired by" YInMn. The new color does not contain any YInMn.[30] Crayola held a contest for more pronounceable name ideas, and announced the new color name, "Bluetiful", on 14 September 2017.[33][34][35] The new crayon color was made available in late 2017.
In artists' pigments
In June 2016, an Australian company, Derivan, published experiments using YInMn within their artist range (Matisse acrylics),[36] and subsequently released the pigment for purchase.[30]
As of April 2021, Golden Paints has commercially licensed and sourced the pigment from Shepherd Color Company. According to Golden, the supply of the raw pigment is extremely limited.[37] Shephard Color Company received the required environmental and safety approvals to sell the pigment in the U.S. in 2020.[38]
Gamblin Artists Colors made a first Limited Edition batch of YInMn Blue in November 2020.[39]
^The color coordinates were obtained from Smith et al. 2016 for the optimal blue pigment, which has the composition YIn0.8Mn0.2O3. The CIELAB coordinates (L = 34.6, a = 9.6, b = −38.9 in table 1) were converted using an online tool.
References
^ abcdefgSmith, Andrew E.; et al. (2 December 2009). "Mn3+ in Trigonal Bipyramidal Coordination: A New Blue Chromophore". Journal of the American Chemical Society. 131 (47): 17084–17086. doi:10.1021/ja9080666. ISSN0002-7863. PMID19899792.
^Zigan, F. & Schuster, H. D. (1972). "Verfeinerung der Struktur von Azurit, Cu3(OH)2(CO3)2, durch Neutronenbeugung" [Refinement of the structure of azurite Cu3(OH)2(CO3)2 by neutron diffraction]. Zeitschrift für Kristallographie (in German). 135 (5–6): 416–436. Bibcode:1972ZK....135..416Z. doi:10.1524/zkri.1972.135.5-6.416. ISSN0044-2968. S2CID95738208.
^Sandor, S.; et al. (July–September 1985). "Sulphonated phthalocyanine induced caudal malformative syndrome in the chick embryo". Romanian Journal of Morphology and Embryology. 31 (3): 173–181. PMID2931590.
^Gettens, Rutherford John & Stout, George Leslie (1966). Painting Materials: A Short Encyclopaedia. New York: Dover Publications. ISBN0-486-21597-0. OCLC518445.