Antiferromagnetic interactions on geometrically frustrated lattices such as the fcc lattice can result in novel magnetic states and structures. Ba2CoMoO6 is an fcc antiferromagnet ordering at 27 K with magnetic Co2+ ions displaying an unquenched orbital moment. These orbital effects are expected to play a significant role in the magnetic properties. We have produced the series Ba2Co1-xZnxMoO6 where the coupling between sites on the fcc lattice is randomly disrupted by diamagnetic Zn2+. Unexpectedly the net antiferromagnetic interactions become stronger upon dilution reaching a maximum at x = 0.25. We will use two days on GEM to examine the magnetic ordering, and any associated structural distortions and orbital ordering of compositions x = 0, 0.15, 0.25 and 0.5. This will unambiguously show the impact of any orbital-ordering on the bonding and resultant magnetic structure.