Structure of La2@C80 studied by La K-edge XAFS

The structure of La2@C80 is studied by La K-edge XAFS from 40 to 295 K. The distances between the La atom and the first nearest C atoms have been determined to be 2.42(1) A at 40 K and 2.44(2) A at 295 K, and those between the La atom and the second nearest C atoms to be 2.97(2) A at 40 K and 2.98(3) A at 295 K. The La–La distance has been determined to be 3.90(1) A at 40 K and 3.88(2) A at 295 K. The temperature dependence of the mean-square displacement of La–C is also studied to get an insight into the dynamical behavior of two La atoms in the C80 cage.