Hi all,

I have collected  a data at 2.9 and the solved the structure using phaser . the space group comes to be P2 21 21. There are 4 molecules in Assymetric unit and an octamer is generated according to the symmetry. But after repeated rounds of rigid body refinement with REFMAC5 and model building with coot  the R factor had been struck at 40% and R free at 50%. 

So my first question is whether my solution after phaser is correct. And if it is how can i lower the  R factor and Rfree.

The second question is it possible to have such a large difference between R factor and R free.

Thanks in advance