bromine byproducts: N2, HBr; anhyd. CF3SO3H is added to (Os(NH3)5(N2))Cl2, liq.Br2 is added, const. flow of N2 or Ar commenced to stir soln., temp. maintained at 50-60°C, when N2 evolution ceased, soln. heated to 110°C, after no Br2 remains, soln. cooled to room temp.; soln. is cooled to 5°C, anhyd. diethyl ether added dropwise, cream ppt. is formed, collected, air-dried, solid washed (anhyd. diethyl ether) until washings colorless, dried, purified by boiling suspn. in chloroform; elem. anal.;