ideal O3'-C3' bond in *geo is 1.422, which interestingly matches C3*-O3* in `modules/chem_data/geostd/t/data_TD.cif`.
This is expected. I would be worried if they didn't match. So, 1.422 is what actually used.
`elbow.where_is_that_cif_file DT` pointed me to `${CLIB}/data/monomers/d/DT.cif`, where O3'-C3' is (now, but may be not at time of *geo generation) 1.431.
What is ${CLIB} ? I'm wondering because Phenix distribution does not have "data/monomers" folders (if I remember correctly).
Pavel