The free r factor 90%of X-ray current 10% of X-ray amplitudes model amplitudes model-derived amplitudes R=EIlFobsl-IF alcl/>Fobsl rere=2IIFobsl-IF alcl I/>1FobsI change model assess modelThe Free R factor current model 90% of X-ray amplitudes R = Σ||Fobs calc||/Σ|Fobs| model-derived amplitudes change model 10% of X-ray amplitudes Rfree = Σ||Fobs calc||/Σ|Fobs| assess model | - |F | - |F