A New Energy-Saving Pigment Comes out of the Blue

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Just when you think there is nothing new under the sun, discoveries come out of the blue. This was literally the case for scientists who discovered a new blue pigment.

A nontoxic blue pigment was developed at Oregon State University
Copyright: Mas Subramanian

Researchers at Oregon State University have patented a blue pigment that is environmentally friendly and nontoxic. This is good news, because many inorganic blues are toxic or cause cancer, such as Prussian blue, cobalt blue, or ultramarine blue.

Even better news: The new blue color has the property of reflecting sunlight, especially in the infrared (heat) part of the spectrum. It is about 40% higher in reflectivity than most blue colors. This could prove to be ideal for paints used on cars, roofs, and other applications where keeping cool is desirable.

A “cool roof” could reflect much of the sun’s heat and help reduce the amount of air conditioning required to keep the temperature inside at a comfortable level. Because the paint is reflecting much of the energy, it tends to last longer as it is not broken down by the absorbed energy.

The compound was discovered by chance in the laboratory of Mas Subramanian, a professor of materials science at Oregon State University. A student in the lab heated a sample of manganese oxide (which is black) to 2,000 oF. When it came out of the oven, it had been transformed into a bright blue color.

Subsequent analysis showed the compound had a trigonal bipyramidal structure—the shape of two pyramids pointing in opposite directions and joined at a triangular base. The central manganese atom is surrounded by five oxygen atoms. But other compounds—yttrium oxide and indium oxide—are required to stabilize the blue crystals.

 

If the new blue paint is used on rooftops across the nation, there really will be something new under the sun!

—Michael Tinnesand

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