(1r,3r,5s)-4-[4-[4-[(1r,3s,5r)-3-hydroxy-8,8-dimethyl-8-azoniabicyclo[3.2.1]octan-4-yl]phenyl]phenyl]-8,8-dimethyl-8-azoniabicyclo[3.2.1]octan-3-ol;dibromide