The isomorphous structures of ethyl-2,3-dihydro-2-benzofuranyl)]-2-imi
dazolinium [(+)-efaroxan cation] chloride, C13H17N2O+.Cl-, and bromide
, C13H17N2O+.- Br-, have been determined. The absolute configuration o
f the active molecule (efaroxan) could be resolved only in the hydrobr
omide salt, the structure of which is reported. (+)-Efaroxan has the R
configuration.