The synthesis of a new, stable, inorganic pigment is an extremely rare event in modern chemistry. Color is a product of specific chemical structures that absorb and reflect light, and creating a novel structure with lasting qualities is a significant scientific challenge. For centuries, the palette of usable, non-fading colors has been surprisingly limited, making the discovery of a truly new color-generating compound a major breakthrough.
The Most Recent Color Discovery
The most recent addition to the palette of inorganic pigments is a vivid shade of blue, accidentally created in 2009 at Oregon State University. This new material was officially named YInMn Blue, derived from the chemical symbols of its constituent elements: Yttrium (Y), Indium (In), and Manganese (Mn). The discovery was made by a team led by chemist Mas Subramanian.
The team was originally researching manganese oxides for electronics applications. They combined oxides of yttrium, indium, and manganese, heating the mixture to approximately 1,200 degrees Celsius (2,200 degrees Fahrenheit). When the compound was pulled from the furnace, a vibrant blue powder had formed instead of the expected electronic material, marking the first new blue pigment discovery in over two centuries.
Unique Chemical Properties of the New Pigment
The unique chemical structure of YInMn Blue grants it remarkable physical properties. The vibrant blue hue is caused by the trivalent manganese ion residing in a specific, unusual trigonal bipyramidal coordination within the crystal lattice.
This hexagonal crystal structure is responsible for the pigment’s stability, a property long sought in a blue compound. The pigment is highly resistant to heat, light, and chemical degradation, meaning it does not fade and can withstand high temperatures required for industrial processes. YInMn Blue is also non-toxic and environmentally safe, as it does not contain heavy metals like lead or cadmium.
A scientifically significant property of the pigment is its ability to strongly reflect near-infrared (NIR) radiation. While the pigment absorbs visible light to produce the blue color, it simultaneously reflects a large portion of the sun’s invisible heat-generating radiation. This high total solar reflectance allows coated surfaces to remain significantly cooler when exposed to sunlight.
A History of Synthetic Color Creation
The story of new color discovery is largely a history of chemical synthesis, shifting reliance from rare, expensive natural sources. Before the modern era, blue pigments were challenging to produce; lapis lazuli, the source of Ultramarine, was one of the most sought-after and costly materials. The invention of the first modern synthetic pigment, Prussian Blue, in the early 18th century, marked a turning point.
Prussian Blue, discovered accidentally in Berlin around 1704, was an iron hexacyanoferrate compound that provided a stable, dark blue. This was followed in 1802 by the French chemist Louis Jacques Thénard’s creation of Cobalt Blue, a highly stable aluminum cobalt oxide pigment. These synthetic breakthroughs democratized color, providing consistent and affordable alternatives to mineral and organic dyes.
The period between the discovery of Cobalt Blue and the creation of YInMn Blue represents a nearly 200-year gap in the successful synthesis of a fundamentally new, high-performance inorganic blue pigment. Finding a new crystal structure that can reliably produce a vivid color without toxicity or instability is a difficult task, explaining the long interval between these chemical milestones.
Practical Applications and Modern Relevance
YInMn Blue’s combination of vibrant color, durability, and high near-infrared reflectance provides practical applications across different industries. Its heat-reflective property is particularly valuable for energy efficiency, making it an ideal component for “cool roof” coatings. Using the pigment on building exteriors helps reflect solar heat away, reducing the need for air conditioning and lowering energy costs.
The pigment’s stability and lightfastness make it superior for use in high-performance industrial coatings and plastics that must endure harsh environmental conditions. In the art world, its permanence and non-toxicity offer a safer and more archival alternative to historic pigments like the potentially carcinogenic Cobalt Blue.