We have discovered a novel type of quantum spin liquid in a hexagonal lattice of Ru5+ dimers in Ba3ZnRu2O9, where any traces of the Curie tail or glassy behavior have not been detected down to 50 mK. In addition, we have finely controlled the magnetic ground state from an antiferromagnetic order to the gapless spin liquid state by making a solid solution between Zn2+ and Co2+. We request 3 days on the WISH diffractometer to collect data from the three samples Ba3Co1-xZnxRu2O9 (x=0, 0.2 and 0.4) at temperatures from 4 to 300 K. WISH data are required to observe any magnetic order, and also to study any unusual lattice effects such as the excess [101] microstrain broadening of diffraction peaks at low temperatures associated with spin singlet dimer-formation in the analogue Ba3CaRu2O9 that was revealed from previous WISH data.