Do you have any reason to expect either of these molecules would be in your crystal? The model you build has to fit the density, be consistent with the surrounding environment (which you haven't shared with us) and you have to have some story for how that molecule got in your crystal. Personally I would steer away from industrial compounds and focus more on biological molecules and common additives used in purification and crystallization.
The environment is critical to identifying this molecule. What hydrogen bonds does this molecule make? What charges are near by? Certainly the presence or absence of hydrogen bonds will distinguish between these two compounds before you go to the trouble to build a model of either. Dale Tronrud On 7/17/2013 6:35 AM, Wei Feng wrote:
Dear all, Thank you for your advices. I had tried to use MPD and pyrophosphate etc to fix the density map but all of them were too small. We guess that the molecular formula should be C8H18O2. So we search this formula in google and find two candidate molecules 1: http://flyingexport.en.ecplaza.net/dhad-99-5--137042-689140.html 2: http://en.m.wikipedia.org/wiki/Di-tert-butyl_peroxide Could you tell me how to get the coordinate of these molecules? Thank you for your time! Wei
