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Figure 9
Difference electron-density plots for different refinements of urea. (Left) Refinement with SCAN PAW-HAR without Gram–Charlier expansion. (Right) Refinement with SCAN PAW-HAR with third (N, O) and fourth (N, O) degree Gram–Charlier expansion.

IUCrJ
Volume 9| Part 2| March 2022| Pages 286-297
ISSN: 2052-2525
https://doi.org/10.1107/S2052252522001385