Supplementary Information
Lone-pair interactions and photodissociation of
compressed nitrogen trifluoride
D. Kurzydłowski, H. B. Wang, I. A. Troyan, and M. I. Eremets
CONTENTS
Fig. S 1 Deconvolution of Raman bands observed in phase II at 3.6 GPa.
Fig. S 2 Deconvolution of Raman bands observed in phase III at 13.4 GPa.
Fig. S 3 Deconvolution of Raman bands observed in phase IV at 32.0 GPa.
Fig. S 4 Deconvolution of Raman bands observed in phase IV’ at 47.7 GPa.
Fig. S 5 Glowing of the sample during laser heating at 3.2 GPa and comparison of sample before and after
heating.
Fig. S 6 Relative enthalpy at 0 K per NF3 unit (referenced to that of P212121) of different polymorphs of NF3
Fig. S 7 Comparison of frequencies of Raman active vibrons calculated for Pnma, Pnma-2 and P212121 with
experimental Raman shifts.
Table S 1 Vibron frequencies (and their symmetries) calculated for Pnma, Pnma-2 and P212121 at 40 GPa.
Table S 2 Pressure coefficients (dν/dp) and zero-pressure frequencies (v0) obtained from a linear fit of the
pressure dependence of Raman frequencies.
Table S 3 Description of various polymorphs of NF3 used in the computational study
Cif files of Pnma, Pnma-2, P21/c and P212121 after geometry optimization at 40 GPa.
1
Fig. S 1 Deconvolution of Raman bands observed in phase II at 3.6 GPa.
Fig. S 2 Deconvolution of Raman bands observed in phase III at 13.4 GPa.
Fig. S 3 Deconvolution of Raman bands observed in phase IV at 32.0 GPa.
Fig. S 4 Deconvolution of Raman bands observed in phase IV’ at 47.7 GPa.
2
Fig. S 5 Glowing of the sample during laser heating at 3.2 GPa and comparison of sample before and after heating.
Fig. S 6 Relative enthalpy at 0 K per NF3 unit (referenced to that of P212121) of different polymorphs of NF3
3
Frequency calculations performed for the isolated NF3 molecule gave the following vibrational frequencies:
ν1 = 998 cm−1, ν3 = 800 cm−1, ν2 = 595 cm−1, and ν4 = 442 cm−1. The obtained frequencies are therefore
underestimated by 33, 108, 51 and 55 cm−1 for ν1-4 with respect to experimental values.1 Therefore in order
to facilited comparison with experiment in the table and plot below the frequencies of a given vibration
manifold (ν1-4) have been shifted by the abovementioned values.
Table S 1 Vibron frequencies (and their symmetries) calculated for Pnma, Pnma-2 and P212121 at 40 GPa.
Pnma
Type of vibration
ν1
ν3
ν2
ν4
Pnma-2
P212121
Symmetry*
ν (cm-1)
Symmetry*
ν (cm-1)
Symmetry*
ν (cm-1)
B1u
1100
B2g
1113
A
1057
B3u
1093
B1u
1096
B1
1047
B2g
1091
Ag
1084
B2
1042
Ag
1088
B3u
1082
B1
1022
B1g
1102
B1g
1080
B2
1072
B3g
1014
B1u
999
B3
1069
B3u
1013
B3u
996
B1
1028
B2g
996
Au
995
B3
986
B1u
975
B2g
979
A
983
B2u
956
B2u
945
B2
975
Ag
951
B3g
943
A
921
Au
947
Ag
932
B3
906
B2g
752
B2g
750
A
765
Ag
741
Ag
737
B
750
B1u
735
B3u
724
B2
749
B3u
717
B1u
722
B3
729
B3g
631
B3g
606
B3
623
B2u
600
B1u
603
A
613
B2g
593
B3u
601
B1
591
B3u
585
B2g
592
B2
588
B1g
584
Ag
581
B3
581
B1u
577
Au
579
A
576
Ag
577
B2u
570
B1
555
Au
571
B1g
562
B2
533
* In case of centrsymmetric structures (Pnma, Pnma-2) underlined modes are Raman active, while the remaining ones are IR
active. For P212121 all modes are Raman active, while B1, B2, and B3 modes are IR active.
4
Fig. S 7 Comparison of frequencies of Raman active vibrons calculated for Pnma, Pnma-2 and P212121 with experimental
Raman shifts.
Table S 2 Pressure coefficients (dν/dp) and zero-pressure frequencies (v0) obtained from a linear fit of the pressure
dependence of Raman frequencies.
Modes of vibration
Type of vibration
ν1
symmetric stretch
ν3
ν2
ν4
asymmetric stretch
symmetric bend
asymmetric bend
ν0 (cm-1)
I*
dν/dp (cm-1/GPa)
III
IV
IV’
I
III
IV
IV’
1033
(1032)
1043
1042
1041
3.0
2.4
2.6
2.5
1029
(1025)
1025
1017
1021
2.2
1.9
2.4
2.2
928
(930)
951
954
970
3.5
3.2
3.2
2.6
880
(879)
892
887
894
1.9
2.8
3.2
2.9
872
882
882
2.7
2.5
2.4
862
867
870
2.4
2.4
2.2
658
663
673
2.2
2.5
2.2
661
670
2.1
1.8
505
514
527
3.2
2.8
2.4
506
515
531
1.8
2.3
1.8
501
510
517
1.5
1.7
1.4
2.4
2.5
2.2
650
(645)
496
(494)
2.7
2.8
Mean
* values in parentheses are from ref. 1.
5
Table S 3 Description of various polymorphs of NF3 used in the computational study
Name
Structure Type
Space group
Z
Ref. / Comments
Ama2
SbF3
Ama2
4
[2]
P212121-2
XeO3
P212121
4
[3]
P212121
AsCl3
P212121
4
[2]
Pna21
AsF3
Pna21
4
[2]
Pnma
NCl3
Pnma
4 (12)*
[2]
Pnma-2
BiF3
Pnma
4
[2]
Pnma-3
PBr3
Pnma
4
[2]
P63
PI3
P63
2
[2]
Rm3
ASI3
Rm3
2
[2]
P213
NH3 at high pressure
P213
4
[4]
Pa–3
NH3 at high pressure
Pa–3
8
[5]
P21/c-2
NH3 at high pressure
P21/c
4
[4]
P212121
4
[4]
P212121-3 NH3 at high pressure
Pc
NH3 at high pressure
Pc
4
[4] / Original Pma2 symmetry removed
P21/c
CF4
P21/c
4
[6] / F2 atoms removed
*The AsCl3-type structure contains 12 molecules per unit cell, but after geometry optimization we obtained a higher-symmetry
cell with Z = 4.
Cif files of Pnma, Pnma-2, P21/c and P212121 after geometry optimization at 40 GPa.
Pnma:
data_findsym-output
_audit_creation_method FINDSYM
_symmetry_space_group_name_H-M "P 21/n 21/m 21/a"
_symmetry_Int_Tables_number 62
_cell_length_a
_cell_length_b
_cell_length_c
_cell_angle_alpha
_cell_angle_beta
_cell_angle_gamma
5.09279
6.21243
3.92750
90.00000
90.00000
90.00000
loop_
_space_group_symop_id
_space_group_symop_operation_xyz
1 x,y,z
2 x+1/2,-y+1/2,-z+1/2
3 -x,y+1/2,-z
4 -x+1/2,-y,z+1/2
5 -x,-y,-z
6 -x+1/2,y+1/2,z+1/2
7 x,-y+1/2,z
8 x+1/2,y,-z+1/2
loop_
_atom_site_label
_atom_site_type_symbol
_atom_site_symmetry_multiplicity
_atom_site_Wyckoff_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
A1 N
4 c -0.01829 0.25000 0.08154 1.00000
B1 F
4 c 0.79411 0.25000 0.83018 1.00000
B2 F
8 d -0.09787 0.07718 0.27499 1.00000
6
Pnma-2:
data_findsym-output
_audit_creation_method FINDSYM
_symmetry_space_group_name_H-M "P 21/n 21/m 21/a"
_symmetry_Int_Tables_number 62
_cell_length_a
_cell_length_b
_cell_length_c
_cell_angle_alpha
_cell_angle_beta
_cell_angle_gamma
5.15959
6.21077
3.83750
90.00000
90.00000
90.00000
loop_
_space_group_symop_id
_space_group_symop_operation_xyz
1 x,y,z
2 x+1/2,-y+1/2,-z+1/2
3 -x,y+1/2,-z
4 -x+1/2,-y,z+1/2
5 -x,-y,-z
6 -x+1/2,y+1/2,z+1/2
7 x,-y+1/2,z
8 x+1/2,y,-z+1/2
loop_
_atom_site_label
_atom_site_type_symbol
_atom_site_symmetry_multiplicity
_atom_site_Wyckoff_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
A1 N
4 c 0.27724 0.25000 0.89293 1.00000
B1 F
4 c -0.02831 0.25000 0.36364 1.00000
B2 F
8 d 0.65248 0.57806 0.31377 1.00000
P21/c:
data_findsym-output
_audit_creation_method FINDSYM
_symmetry_space_group_name_H-M "P 1 21/c 1"
_symmetry_Int_Tables_number 14
_cell_length_a
_cell_length_b
_cell_length_c
_cell_angle_alpha
_cell_angle_beta
_cell_angle_gamma
6.70307
3.89499
5.11746
90.00000
112.29487
90.00000
loop_
_space_group_symop_id
_space_group_symop_operation_xyz
1 x,y,z
2 -x,y+1/2,-z+1/2
3 -x,-y,-z
4 x,-y+1/2,z+1/2
loop_
_atom_site_label
_atom_site_type_symbol
_atom_site_symmetry_multiplicity
_atom_site_Wyckoff_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
A1 N
4 e 0.74860 0.40695 0.64799
B1 F
4 e 0.56963 0.22617 0.63938
B2 F
4 e -0.08589 0.18775 0.79795
B3 F
4 e 0.76161 0.65077 0.84720
1.00000
1.00000
1.00000
1.00000
7
P212121:
data_findsym-output
_audit_creation_method FINDSYM
_symmetry_space_group_name_H-M "P 21 21 21"
_symmetry_Int_Tables_number 19
_cell_length_a
_cell_length_b
_cell_length_c
_cell_angle_alpha
_cell_angle_beta
_cell_angle_gamma
6.09666
7.25738
2.77297
90.00000
90.00000
90.00000
loop_
_space_group_symop_id
_space_group_symop_operation_xyz
1 x,y,z
2 x+1/2,-y+1/2,-z
3 -x,y+1/2,-z+1/2
4 -x+1/2,-y,z+1/2
loop_
_atom_site_label
_atom_site_type_symbol
_atom_site_symmetry_multiplicity
_atom_site_Wyckoff_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
A1 N
4 a 0.29932 0.29046 -0.04332
B1 F
4 a 0.29297 0.12088 0.73296
B2 F
4 a 0.12795 0.38342 0.73259
B3 F
4 a 0.47758 0.36985 0.73878
1.00000
1.00000
1.00000
1.00000
References
1
M. Gilbert, P. Nectoux, and M. Drifford, J. Chem. Phys. 68, 679 (1978).
2
J. Galy and R. Enjalbert, J. Solid State Chem. 44, 1 (1982).
3
D. H. Templeton, A. Zalkin, J. D. Forrester, and S. M. Williamson, J. Am. Chem. Soc. 85, 817 (1963).
4
C. J. Pickard and R. J. Needs, Nat. Mater. 7, 775 (2008).
5
G. I. G. Griffiths, R. J. Needs, and C. J. Pickard, Phys. Rev. B 86, 144102 (2012).
6
Y. A. Sataty, J. Chem. Phys. 62, 1094 (1975).
8