Hello Phenix users,<br><br>I have tetrabutylphosphonium in my crystal. I found a similar compound tetrabutylammonium (PDB residue name TBA) which are found in several PDB entries. <br><br>Usually I draw the new compound in 2-D format and convert to 3D and then create restrain files. In this case, considering N and P are very similar, will the TBS be helpful for elbow to generate restrains for tetrabutylphosphonium? <br><br>Thanks<br><br>Rongjin Guan <br>