The crystal structures of PEO3:LiBF4, (diglyme)2:LiBF4, and (diglyme):LiBF4 have been determined
and are compared. The helical conformation of each polymer chain and the stacking of neighboring
chains in the structure of the PEO complex is similar to that found in the complexes with Li imide and
Li triflate salts of the same PEO:salt ratio. Both PEO3:LiBF4 and (diglyme):LiBF4 have similar coordination
around Li+, i.e., 3 ether oxygens and 2 fluorines from two BF4
- anions. However, in the former each
anion bridges two neighboring Li+ cations located along the PEO chain axis forming a continuous chain
−BF4
-−Li+−BF4
-−Li+− whereas in (diglyme):LiBF4 two BF4
- anions bridge between pairs of Li+
forming discrete diglyme−Li+−(BF4
-)2−Li+−diglyme units that are linked to their neighbors predominantly by van der Waals bonding. The (diglyme)2:LiBF4 structure is compared with those of
PEO6:LiSbF6 (no PEO6:LiBF4 exists) and (diglyme)2:LiSbF6. In both cases the Li+ cations are 6-coordinated
by three ether oxygens from two different diglymes and there is no anion coordination.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.