Synthesis and structure of BaxC70

We have investigated the structural sequence of BaxC70 binary systems. X-ra y diffraction measurements revealed that there exist at least four stable p hase at x=3, 4, 6, and 9. Among them, structural models are presented for B a3C70 and Ba9C70. Ba3C70 takes an analogous structure to A15-Ba3C60, but th e unit cell is distorted to tetragonal with the cell doubling. Ba9C70 is fe e, involves a distorted cube of Ba8 in the octahedral interstices. This x=9 structure is also known in K9C70 as a saturated phase.