'Sea urchins'—another novel form of carbon

Abstract

Since the discovery of C 60 , research on carbon has turned up one new remarkable structure after another based on the element. And because the discoverers of C 60 playfully dubbed the molecule buckminsterfullerene, they and other investigators have appended a variety of playful—and sometimes silly—names to the new carbon compounds. Now, chemists at DuPont and SRI International have produced urchins, structures in which single-layer carbon nanotubes radiate in three dimensions from amorphous gadolinium-carbon cores or single-crystal GdC 2 cores [ Nature , 366 ,637 (1993)]. Needless to say, in transmission electron microscopy (TEM) images, the new species look a lot like sea urchins. Shekhar Subramoney, of DuPont's Experimental Station, Wilmington, Del., and Rodney S. Ruoff, Donald C. Lorents, and Ripudaman Malhotra, of SRI's Molecular Physics Laboratory, Menlo Park, Calif., previously had produced single crystals of LaC 2 encapsulated in carbon (C&EN, Jan. 18, 1993, page 34). Those particles consi...