Courtesy Oregon State University

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A Truer Blue

A brilliant new pigment caught scientists by surprise

March 13, 2017

By Jennifer Hackett

For the millions of people around the world who say blue is their favorite color, here’s some good news: There’s a new kind of brilliant blue to love.

Mas Subramanian, a materials scientist at Oregon State University, stumbled upon the new blue by chance. His research team focuses on developing new materials for electronics—nothing to do with creating color. Part of their process involves mixing, grinding, and heating chemicals. One day, Subramanian saw a graduate student pulling samples of a mixture out of the furnace. “I saw this vivid, intense blue,” he says. “I was shocked. I’d never seen anything like it.”

It turned out that this mixture was a new pigment. Pigments are used to give color to paints, plastics, fabrics, and even foods. Blue pigments have always caused problems: They’re frequently unstable, meaning they fade or change color over time. They’re also difficult to find in nature, and often toxic when created artificially. The last major new blue pigment, cobalt blue, was discovered in the early 1800s. It’s still used in many paints and other products today, but making it requires workers to handle toxic materials.

Courtesy Casey Chaffin

Mas Subramanian holds up a sample of his new blue pigment.

Subramanian’s blue compound—a substance made of two or more elements—is formed from the elements yttrium, indium, manganese, and oxygen. In honor of its chemical composition, the pigment is named YInMn (pronounced YIN-min) blue.

In tests, YInMn blue has proved to be more durable than cobalt blue. Even better, its ingredients are completely nontoxic. Subramanian and his colleagues patented their creation, and the Shepherd Color Company will soon make and sell it. And don’t worry if your favorite color isn’t blue: Other bright colors using the same chemical structure, including greens, yellows, and purples, are on the way.

YInMn blue is the latest in a long line of blue pigments used throughout history for art, clothing, and jewelry.

INDIGO DYE: Circa 4184 B.C.E.

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Best known for giving denim jeans their signature blue, indigo dye is made of woad, a plant common in Asia and Africa. It was introduced to Europe in the 15th century but has been used for thousands of years.

EGYPTIAN BLUE: Circa 2575-2467 B.C.E.

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The first artificial blue pigment was created in ancient Egypt. It’s made by mixing sand, copper, and natron (a type of salt), and then heating the mixture.

ULTRAMARINE: Circa 500-600 C.E.

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The original pigment was made of the semiprecious stone lapis lazuli, which was ground up and purified. It was later imported into Europe, earning it the name ultramarine, from the Latin for “beyond the sea.”

PRUSSIAN BLUE: Circa 1706

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The first modern synthetic pigment was discovered by accident when a chemist who was trying to make red added a mixture that included the chemical cyanide to his paint. Today, the color’s name refers to the coats Prussian soldiers wore.

CERULEAN: 1789

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Made of copper and cobalt oxide, this pigment produces a sky blue color. But it can turn green or fade. The name cerulean was used 200 years before they made the pigment!

COBALT BLUE: 1802

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Natural cobalt—based on the metal—has been used for centuries, most notably in Chinese porcelain in the 8th century. But the first synthetic cobalt blue pigment was made by French chemist Louis Jacques Thenard.

PHTHALO BLUE: Circa 1930

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Phthalo blue is a brilliant, light blue used in inks and solar cells. It’s made of copper and a chemical called phthalocyanine.

WRITING RATIOS

Each of Subramanian’s pigments is made up of a ratio of elements written in a chemical formula. Ratios are comparisons between two or more quantities.

There are three parts to each pigment’s chemical formula. The first is the element yttrium (Y). The second is a combination of metal elements that determines the pigment’s color. This is referred to as the “B metal” and is shown in brackets. The last part is oxygen (O).

Write ratios based on the chemical formulas for the new pigments. Each element’s chemical symbol starts with an uppercase letter and is 1 or 2 letters long. Any chemical symbol without a number in small script represents 1 atom.