M@C60

It had been expected, before the first macroscopic production and extraction of La@C82, that metallofullerenes based on the C60 cage would be the most abundant metallofullerenes that were prepared in macroscopic amounts, as was the case in empty fullerenes. This is simply because C60 is the most abundant fullerene which can be easily produced by either the arc-discharge or the laser-furnace method. To fully understand "the M@C60 mystery," the structural characterization/determination of purified M@C60 metallofullerenes using X-ray diffraction is definitely required. One of the most exciting and enticing topics on metallofullerenes is whether or not a superconductive metallofullerene could exist as a high-temperature fullerene superconductor such as alkaline-doped C60. Scaling-up of production and isolation of metallofullerenes is possible by using a large-scale arc-discharge system as well as by using a preparative HPLC system with a large column together with the TiCl4 separation technique of metallofullerenes from empty fullerenes.