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User-friendly alkali metals

Alkali metals can be violently reactive. Chemists have tried to control this reactivity by dispersing the metals in inert solids or in liquid ammonia, but have not met with great success outside the lab. A team of chemists at Michigan State University and start-up company SiGNa Chemistry led by James L. Dye and Michael Lefenfeld has now developed a method to absorb alkali metals into silica gel to form powders that are up to 60 mol% of the metal, making them safer and more practical for industrial applications (J. Am. Chem. Soc., published online June 14, dx.doi.org/10.1021/ja051786+). When sodium or a sodium-potassium alloy is heated above 150 °C, the molten metal can be mixed with silica gel to form different types of powders ranging from metal-silica adducts to metal-silicon nanoparticles, depending on the temperature. The powders can be used in batch reactions or as reducing agents in pharmaceutical and petrochemical processes. They also can be reacted with water to produce hydrogen. SiGNa Chemistry initially plans to use the powders to power hydrogen fuel cells in portable electronic devices.