FLUORINE

NANCE DICCIANI,SPECIALTY MATERIALS, HONEYWELL

Fluorine is an element of many mosts: It is the most reactive of all of the elements, the most powerful oxidizing agent, and the most electronegative. But its true strength and the secret of its success lies in the compounds it forms--some of the most stable and inert substances known to man. These compounds have enabled a steady stream of scientific and commercial advances: Staying warm and dry in a downpour, cooking with the ease of a nonstick pan, and beaming a "cavity free" smile are all available thanks to the fluorine atom.

Fluorine occurs naturally as a mono-isotope ¹⁹F₉ and is not a rare element: About 0.07% of Earth's crust is comprised of fluorine, mostly as the minerals fluorapatite and fluorite (CaF₂), the main constituent of the ore fluorspar. Although very few naturally occurring organofluorine compounds are known to exist, many man-made fluorochemicals have been developed over the years, all of which have fluorspar as their starting point. The unique properties, pervasive influence, and lasting impact of these compounds have given fluorine a distinction as "the little atom that could."

FLUORINE AT A GLANCE Name: From the Latin fluere, flow. Atomic mass: 19.00. History: Fluorine was first identified by Karl W. Scheele in 1771. It was first isolated in 1886 by French chemist F. Henri Moissan. His reward was the Nobel Prize for Chemistry in 1906. Occurrence: Found in fluorspar, cryolite, and other minerals. Appearance: Pale yellow gas. The free element has a characteristic odor. Behavior: Fluorine is the most reactive element and reacts with practically all substances. It reacts with water to produce oxygen and ozone. Fluorine gas is corrosive and toxic. Uses: An essential trace element for mammals. Fluorine and its compounds are used in producing uranium and more than 100 commercial fluorochemicals. Certain fluorocarbons were used in air conditioning and refrigeration but have been phased out because they damaged the ozone layer.

LIFTOFF! The National Space Centre in Leicester, England, features a Rocket Tower composed of ethylene-tetrafluoroethylene copolymer. MARTIN BOND/SCIENCE PHOTO LIBRARY

Fluorochemicals touch millions of peoples' lives in meaningful ways every day, especially in health care and quality-of-life products. At the top of a very long list: the inorganic fluorides used in drinking water and dental products, the one out of every five active pharmaceutical products that is fluorinated, and the synthetic blood substitutes and inhalation drug delivery systems that use fluorocarbons.

Fluorochemicals also underscore a wide range of commercial successes. Growth in the industrial and household refrigeration and air conditioning industries is based largely on the use of low-toxicity, nonflammable, and energy-efficient fluorocarbon fluids. Fluoropolymers and fluoroelastomers are used widely in homes, buildings, automobiles, aerospace applications, and wherever high performance is required--performance such as excellent thermal, flame, electrical, chemical, and solvent resistance and low oxygen and moisture permeability. Other low-molecular-weight perfluoroalkyl-based materials provide oil-, water-, and soil-repellent surface properties for textile, fiber, and paper coatings; and similar materials are used as surfactants to stabilize aqueous fire-fighting foams. Fluorocarbons are also used as fire extinguishants in aerospace and other critical areas. Modern high-energy-density lithium-ion batteries used in handheld electronic devices rely on LiPF₆.

And there's even more. Consider, for example, agrochemicals, where about 17% of active materials used as pesticides and fungicides are based on fluorinated compounds. The manufacture of silicon chips relies on the wet and dry etch processes utilizing materials such as ultra-high-purity HF and NF₃. Elemental fluorine is used to prepare UF₆, used by the nuclear industry for uranium enrichment. Electrical utilities rely on the high dielectric strength of SF₆, also manufactured using direct elemental fluorination, for high-voltage circuit breakers and transformers. And within the chemical processing industries, catalysts include BF₃ and SbF₅, KF is used as a fluorinating agent, and AlF₃ is used to process aluminum.

Today, the innovative use and application of fluorine chemistry and fluorinated materials continues unbounded, especially in growth areas of optoelectronics, electronics, life sciences, and high-performance materials. And what's on the horizon is even more exciting: Imagine "smart dust" where supermicrosensors allow us to gather vital data on a scale previously unimaginable; new materials capable of making more effective repairs to the human body; and pharmaceuticals customized for use, compatibility, and delivery.

It's hard not to get caught up in the future potential of fluorine chemistry. Recently, following a speech I gave to an industry group, a chemist half-jokingly told me, "I'm glad to see the fluorine (F) pin on your jacket lapel, because without it, you're not fulfilling your role as a leader in the chemical industry." I couldn't agree more. In the 117 years since it was first isolated by Henri Moissan, fluorine has become a powerful foundation for chemical exploration, discovery, and innovation. Who would have imagined that fluorine would serve as the foundation for so many of today's modern marvels and tomorrow's most promising innovations?

Nance Dicciani is president and CEO of Specialty Materials, a strategic business group of Honeywell. She holds a Ph.D. in chemical engineering and has more than 25 years of experience in the chemical industry.

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