Validation of missed space-group symmetry in X-ray powder diffraction structures with dispersion-corrected density functional theory

More than 600 molecular crystal structures with correct, incorrect and uncertain space-group symmetry were energy-minimized with dispersion-corrected density functional theory (DFT-D, PBE-D3). For the purpose of determining the correct space-group symmetry the required tolerance on the atomic coordinates of all non-H atoms is established to be 0.2 Å. For 98.5% of 200 molecular crystal structures published with missed symmetry, the correct space group is identified; there are no false positives. Very small, very symmetrical molecules can end up in artificially high space groups upon energy minimization, although this is easily detected through visual inspection. If the space group of a crystal structure determined from powder diffraction data is ambiguous, energy minimization with DFT-D provides a fast and reliable method to select the correct space group.

Computing details

(AZAFAJ_reint_Hadded)

Crystal data

Monoclinic, P2_1/c	c = 14.153494 Å
a = 5.025567 Å	β = 106.655199°
b = 13.347063 Å

Data collection

h = →	l = →
k = →

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Biso*/Beq
N1	−1.819389	0.887880	−0.933817
C1	−1.611432	0.888827	−0.856074
C10	−1.998676	0.974924	−0.950952
C2	−1.411635	0.806070	−0.830018
C3	−1.167807	0.818621	−0.751877
C7	−1.461355	0.713837	−0.880516
O1	−1.112344	0.910346	−0.704976
C4	−0.972565	0.739746	−0.724334
C6	−1.271449	0.636238	−0.852307
C8	−1.160215	0.913910	−0.609264
O2	−0.740213	0.759855	−0.648924
C5	−1.027030	0.648457	−0.774785
C9	−0.538470	0.681019	−0.620079
H1	−1.573315	0.952900	−0.804582
H2	−1.938272	1.030540	−0.890536
H3	−2.211592	0.949780	−0.956189
H4	−1.652194	0.705552	−0.940526
H5	−1.311731	0.563854	−0.889518
H6	−1.021410	0.861952	−0.557533
H7	−1.116585	0.991249	−0.583494
H8	−1.378025	0.895498	−0.615233
H9	−0.882765	0.586037	−0.754193
H10	−0.463734	0.657553	−0.682468
H11	−0.366136	0.712369	−0.561699
H12	−0.626429	0.617088	−0.590391

(DEDVEO_reint_Hadded)

Crystal data

Orthorhombic, Pca2_1	b = 5.625461 Å
a = 12.937941 Å	c = 18.006478 Å

Data collection

h = →	l = →
k = →

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Biso*/Beq
C1	0.954993E-1	0.192504	0.580405
C2	0.325551E-1	0.402931	0.566741
C4	0.180159	0.152420	0.522644
C10	0.140496	0.191328	0.662137
C3	−0.224819E-1	0.573284	0.555101
C5	0.200942	0.318748	0.466886
C9	0.238679	−0.575151E-1	0.525017
C11	0.218394	0.375778	0.671458
C13	0.550074E-1	0.198130	0.720493
C6	0.278003	0.276470	0.414128
C8	0.316754	−0.984466E-1	0.472981
C12	0.284485	0.526784	0.678325
C14	0.427367E-1	0.390891	0.768811
C18	−0.127181E-1	0.396742E-2	0.726775
C7	0.336416	0.679407E-1	0.416996
C15	−0.339673E-1	0.388291	0.823464
C17	−0.900181E-1	0.220656E-2	0.780934
C16	−0.100316	0.193699	0.829944
H1	0.433324E-1	0.372696E-1	0.577983
H2	0.179960	0.181552E-1	0.667892
H3	−0.744631E-1	0.716918	0.543361
H4	0.156324	0.483015	0.465157
H5	0.223106	−0.192303	0.567204
H6	0.292528	0.407431	0.370706
H7	0.361840	−0.261804	0.476222
H8	0.344825	0.655711	0.684543
H9	0.948278E-1	0.542605	0.764145
H10	−0.477988E-2	−0.148733	0.689695
H11	0.397005	0.357256E-1	0.376134
H12	−0.411826E-1	0.538852	0.861256
H13	−0.141978	−0.149873	0.784841
H14	−0.159914	0.189408	0.872733