Charge-density analysis in polymorphs of urea–barbituric acid co-crystals

Gryl, M.; Krawczuk-Pantula, A.; Stadnicka, K.

doi:10.1107/S0108768111002412

Charge-density analysis in polymorphs of urea-barbituric acid co-crystals

M. Gryl, A. Krawczuk-Pantula and K. Stadnicka

High-resolution single-crystal X-ray diffraction measurements at 100 K were performed for the two polymorphs of urea-barbituric acid co-crystals: (I) P2₁/c and (II) Cc. Experimental and theoretical charge density and its properties were analysed for (I) and (II) in order to confirm the previous observation that in the polymorphs studied the barbituric acid molecules adopt different mesomeric forms, leading to different hydrogen-bond systems. Koch and Popelier criteria were applied to distinguish between hydrogen bonds and van der Waals interactions in the structures presented.

Keywords: barbituric acid; urea; addition compounds; polymorphism; charge-density analysis.

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S0108768111002412/gw5010sup1.cif Contains datablocks global, I, II
	Structure factor file (CIF format) https://doi.org/10.1107/S0108768111002412/gw5010Isup2.hkl Contains datablock I
	Structure factor file (CIF format) https://doi.org/10.1107/S0108768111002412/gw5010IIsup3.hkl Contains datablock II
	Portable Document Format (PDF) file https://doi.org/10.1107/S0108768111002412/gw5010sup4.pdf Extra figures and tables

CCDC references: 822663; 822664

Computing details top

For both compounds, data collection: KappaCCD Server Software (Nonius, 1997); cell refinement: DENZO-SMN (Otwinowski & Minor, 1997); data reduction: HKL DENZO and SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: Volkov et al., (2006); molecular graphics: PLATON (Spek, 2003); ORTEP-3 for Windows (Farrugia, 1997); Mercury (Version 1.4; Macrae et al., 2006); software used to prepare material for publication: Volkov et al., (2006).

Figures top

(I) 2,4,6(1H,3H,5H)-Pyrimidinetrione urea addition compound top

Crystal data top

C₄H₄N₂O₃·CH₄N₂O	F(000) = 392
M_r = 188.15	D_x = 1.644 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
a = 7.8123 (1) Å	Cell parameters from 6744 reflections
b = 6.9384 (1) Å	θ = 1.0–47.6°
c = 14.1179 (3) Å	µ = 0.14 mm⁻¹
β = 96.727 (1)°	T = 100 K
V = 759.99 (2) Å³	Plate, pale yellow
Z = 4	0.45 × 0.37 × 0.05 mm

Data collection top

KappaCCD diffractometer	7049 independent reflections
Radiation source: fine focus sealed tube	5793 reflections with > 2/s(I)
Horizontally mounted graphite crystal monochromator	R_int = 0.029
Detector resolution: 9 pixels mm^-1	θ_max = 47.6°
ω scans atχ=55°	h = −16→16
Absorption correction: multi-scan HKL DENZO and SCALEPACK (Otwinowski & Minor, 1997)	k = 0→14
T_min = 0.939, T_max = 0.993	l = 0→28
13521 measured reflections

Refinement top

Refinement on F	276 parameters
Least-squares matrix: full	0 restraints
R[F² > 2σ(F²)] = 0.036	H-atom parameters constrained
wR(F²) = 0.029	w1 = 1/[s²(F_o)]
S = 1.36	(Δ/σ)_max = 0.001
5793 reflections	Δρ_min = −0.44 e Å⁻³

Crystal data top

C₄H₄N₂O₃·CH₄N₂O	V = 759.99 (2) Å³
M_r = 188.15	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 7.8123 (1) Å	µ = 0.14 mm⁻¹
b = 6.9384 (1) Å	T = 100 K
c = 14.1179 (3) Å	0.45 × 0.37 × 0.05 mm
β = 96.727 (1)°

Data collection top

KappaCCD diffractometer	7049 independent reflections
Absorption correction: multi-scan HKL DENZO and SCALEPACK (Otwinowski & Minor, 1997)	5793 reflections with > 2/s(I)
T_min = 0.939, T_max = 0.993	R_int = 0.029
13521 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.036	276 parameters
wR(F²) = 0.029	0 restraints
S = 1.36	H-atom parameters constrained
5793 reflections	Δρ_min = −0.44 e Å⁻³

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
O(2)	0.12430 (3)	−0.26341 (4)	0.58557 (2)	0.015
O(4)	0.48066 (4)	0.08484 (5)	0.79397 (3)	0.015
O(6)	−0.07456 (5)	0.31444 (5)	0.67347 (3)	0.017
O(1)	0.29486 (3)	0.08165 (3)	0.456716 (18)	0.013
N(1)	0.02955 (4)	0.03185 (4)	0.62473 (2)	0.011
N(3)	0.30929 (4)	−0.07636 (4)	0.68093 (2)	0.011
N(2)	0.49881 (4)	0.26216 (5)	0.54367 (3)	0.015
N(4)	0.22515 (4)	0.38318 (5)	0.50054 (3)	0.016
C(2)	0.15181 (5)	−0.11043 (5)	0.62796 (3)	0.011
C(4)	0.04467 (4)	0.20053 (5)	0.67655 (2)	0.011
C(5)	0.21388 (5)	0.23512 (6)	0.73637 (3)	0.013
C(6)	0.34490 (4)	0.07729 (5)	0.74016 (2)	0.011
C(1)	0.33815 (5)	0.23719 (6)	0.49898 (3)	0.011
H(5A)	0.27128	0.365152	0.710028	0.028
H(5B)	0.187412	0.26475	0.809216	0.03
H(1)	−0.08065	0.01112	0.581024	0.027
H(3)	0.404729	−0.172295	0.675519	0.027
H(2A)	0.58414	0.152843	0.544491	0.028
H(2B)	0.528515	0.382294	0.58242	0.028
H(4A)	0.104336	0.362376	0.468322	0.029
H(4B)	0.259089	0.511527	0.530696	0.029

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O(2)	0.01248 (11)	0.01123 (10)	0.02163 (13)	0.00070 (8)	−0.00226 (9)	−0.00558 (9)
O(4)	0.01188 (12)	0.01416 (14)	0.01718 (14)	−0.00012 (10)	−0.00458 (11)	−0.00083 (12)
O(6)	0.01454 (12)	0.01655 (13)	0.01823 (14)	0.00623 (11)	−0.00060 (12)	−0.00408 (13)
O(1)	0.01118 (9)	0.01031 (9)	0.01697 (10)	0.00058 (7)	−0.00200 (7)	−0.00383 (8)
N(1)	0.00865 (10)	0.01036 (10)	0.01265 (11)	0.00111 (8)	−0.00087 (8)	−0.00128 (9)
N(3)	0.00884 (10)	0.01020 (10)	0.01395 (11)	0.00059 (8)	−0.00132 (8)	−0.00117 (9)
N(2)	0.01129 (11)	0.01203 (12)	0.02002 (14)	0.00025 (9)	−0.00378 (10)	−0.00350 (10)
N(4)	0.01182 (12)	0.01090 (11)	0.02412 (15)	0.00212 (9)	−0.00076 (11)	−0.00458 (11)
C(2)	0.00889 (12)	0.00917 (12)	0.01295 (14)	0.00046 (10)	−0.00078 (11)	−0.00176 (12)
C(4)	0.01063 (12)	0.01158 (12)	0.01139 (12)	0.00242 (10)	0.00036 (10)	−0.00141 (10)
C(5)	0.01247 (14)	0.01319 (13)	0.01322 (14)	0.00170 (11)	−0.00170 (11)	−0.00398 (11)
C(6)	0.00951 (12)	0.01098 (11)	0.01140 (12)	0.00013 (9)	−0.00147 (10)	−0.00050 (10)
C(1)	0.00967 (13)	0.00903 (13)	0.01259 (15)	0.00008 (10)	−0.00042 (12)	−0.00137 (12)
H(5A)	0.026908	0.021576	0.035402	−0.005379	0.001711	0.005472
H(5B)	0.032375	0.038144	0.018682	0.004802	0.003065	−0.002701
H(1)	0.019802	0.027144	0.032159	−0.001904	−0.008677	−0.000684
H(3)	0.018988	0.023462	0.036213	0.003212	−0.000789	−0.005105
H(2A)	0.022482	0.022128	0.038	0.005601	−0.00421	−0.005499
H(2B)	0.025769	0.021116	0.035475	−0.000336	−0.005216	−0.009448
H(4A)	0.018756	0.025377	0.041203	0.001406	−0.004512	−0.006716
H(4B)	0.02568	0.018772	0.04142	0.00056	−0.001842	−0.009378

Geometric parameters (Å, º) top

O(2)—C(2)	1.2250 (4)	N(2)—C(1)	1.3483 (5)
O(4)—C(6)	1.2312 (4)	N(2)—H(2A)	1.0090
O(6)—C(4)	1.2185 (5)	N(2)—H(2B)	1.0090
O(1)—C(1)	1.2601 (4)	N(4)—C(1)	1.3455 (5)
N(1)—C(2)	1.3706 (5)	N(4)—H(4A)	1.0090
N(1)—C(4)	1.3780 (4)	N(4)—H(4B)	1.0090
N(1)—H(1)	1.0090	C(4)—C(5)	1.5023 (5)
N(3)—C(2)	1.3832 (5)	C(5)—C(6)	1.4956 (5)
N(3)—C(6)	1.3634 (5)	C(5)—H(5A)	1.0920
N(3)—H(3)	1.0090	C(5)—H(5B)	1.0920

C(2)—N(1)—C(4)	125.31 (3)	C(4)—C(5)—C(6)	117.17 (3)
C(2)—N(3)—C(6)	124.74 (3)	O(4)—C(6)—N(3)	120.71 (3)
O(2)—C(2)—N(1)	121.74 (3)	O(4)—C(6)—C(5)	121.83 (3)
O(2)—C(2)—N(3)	120.41 (3)	N(3)—C(6)—C(5)	117.45 (3)
N(1)—C(2)—N(3)	117.85 (3)	O(1)—C(1)—N(2)	121.01 (3)
O(6)—C(4)—N(1)	120.95 (3)	O(1)—C(1)—N(4)	120.82 (4)
O(6)—C(4)—C(5)	122.35 (3)	N(2)—C(1)—N(4)	118.17 (3)
N(1)—C(4)—C(5)	116.69 (3)

(II) 2,4,6(1H,3H,5H)-Pyrimidinetrione urea addition compound top

Crystal data top

C₄H₄N₂O₃·CH₄N₂O	F(000) = 392
M_r = 188.15	D_x = 1.588 Mg m⁻³
Monoclinic, Cc	Mo Kα radiation, λ = 0.71073 Å
a = 16.0474 (5) Å	Cell parameters from 3979 reflections
b = 5.0280 (2) Å	θ = 1.0–53.9°
c = 10.3879 (3) Å	µ = 0.14 mm⁻¹
β = 110.093 (2)°	T = 100 K
V = 787.15 (5) Å³	Block, colourless
Z = 4	0.35 × 0.32 × 0.15 mm

Data collection top

KappaCCD diffractometer	6342 independent reflections
Radiation source: fine focus sealed tube	5464 reflections with > 2/s(I)
Horizontally mounted graphite crystal monochromator	R_int = 0.042
Detector resolution: 9 pixels mm^-1	θ_max = 52.5°
ω scans atχ=55°	h = −36→33
Absorption correction: multi-scan HKL DENZO and SCALEPACK (Otwinowski & Minor, 1997)	k = 0→11
T_min = 0.953, T_max = 0.980	l = 0→23
6342 measured reflections

Refinement top

Refinement on F	0 restraints
Least-squares matrix: full	H-atom parameters constrained
R[F² > 2σ(F²)] = 0.038	w1 = 1/[s²(F_o)]
wR(F²) = 0.027	(Δ/σ)_max = 0.00001
S = 1.04	Δρ_max = 0.30 e Å⁻³
3775 reflections	Δρ_min = −0.36 e Å⁻³
274 parameters

Crystal data top

C₄H₄N₂O₃·CH₄N₂O	V = 787.15 (5) Å³
M_r = 188.15	Z = 4
Monoclinic, Cc	Mo Kα radiation
a = 16.0474 (5) Å	µ = 0.14 mm⁻¹
b = 5.0280 (2) Å	T = 100 K
c = 10.3879 (3) Å	0.35 × 0.32 × 0.15 mm
β = 110.093 (2)°

Data collection top

KappaCCD diffractometer	6342 independent reflections
Absorption correction: multi-scan HKL DENZO and SCALEPACK (Otwinowski & Minor, 1997)	5464 reflections with > 2/s(I)
T_min = 0.953, T_max = 0.980	R_int = 0.042
6342 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.038	0 restraints
wR(F²) = 0.027	H-atom parameters constrained
S = 1.04	Δρ_max = 0.30 e Å⁻³
3775 reflections	Δρ_min = −0.36 e Å⁻³
274 parameters

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
O(2)	0.061746 (4)	0.04543 (18)	0.510092 (6)	0.018
O(4)	−0.17166 (8)	0.60643 (16)	0.42353 (11)	0.018
O(6)	−0.16920 (7)	−0.09264 (15)	0.11890 (10)	0.017
O(1)	0.02613 (8)	0.54577 (16)	0.23956 (11)	0.015
N(1)	−0.05186 (8)	−0.01028 (13)	0.30905 (11)	0.014
N(3)	−0.05419 (8)	0.33131 (14)	0.46342 (10)	0.014
N(2)	0.14407 (8)	0.27632 (18)	0.26165 (12)	0.02
N(4)	0.15747 (9)	0.62610 (16)	0.41011 (11)	0.02
C(2)	−0.01091 (8)	0.11902 (14)	0.43125 (10)	0.013
C(4)	−0.13599 (7)	0.42476 (13)	0.38339 (10)	0.013
C(5)	−0.17735 (8)	0.30042 (14)	0.24419 (11)	0.015
C(6)	−0.13438 (8)	0.05101 (14)	0.21783 (10)	0.013
C(1)	0.10629 (8)	0.48377 (15)	0.30219 (11)	0.013
H(1)	−0.020451	−0.167473	0.286118	0.03
H(3)	−0.026827	0.424738	0.55419	0.03
H(5A)	−0.246368	0.258451	0.232305	0.032
H(5B)	−0.180054	0.451748	0.167452	0.031
H(2A)	0.104982	0.166832	0.182503	0.033
H(2B)	0.207184	0.227934	0.31752	0.033
H(4A)	0.129646	0.778832	0.443717	0.034
H(4B)	0.220377	0.571071	0.463401	0.034

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O(2)	0.0150 (3)	0.0210 (3)	0.0145 (3)	0.0050 (3)	0.0003 (2)	−0.0006 (2)
O(4)	0.0183 (3)	0.0177 (3)	0.0175 (2)	0.0049 (2)	0.0048 (2)	−0.0028 (2)
O(6)	0.0165 (3)	0.0154 (2)	0.0162 (2)	0.0003 (2)	0.00021 (18)	−0.0038 (2)
O(1)	0.0131 (3)	0.0159 (3)	0.0131 (2)	0.0022 (2)	0.00188 (19)	0.0000 (2)
N(1)	0.0128 (2)	0.0135 (2)	0.01361 (19)	0.00153 (18)	0.00198 (16)	−0.00133 (17)
N(3)	0.0137 (2)	0.0156 (2)	0.01147 (19)	0.00227 (18)	0.00307 (16)	−0.00102 (17)
N(2)	0.0163 (3)	0.0215 (3)	0.0182 (3)	0.0056 (2)	0.0019 (2)	−0.0043 (2)
N(4)	0.0153 (3)	0.0204 (3)	0.0184 (3)	0.0027 (2)	−0.0009 (2)	−0.0049 (2)
C(2)	0.0128 (3)	0.0141 (3)	0.0115 (2)	0.0020 (2)	0.0026 (2)	0.0000 (2)
C(4)	0.0132 (2)	0.0132 (2)	0.0127 (2)	0.00215 (19)	0.00363 (17)	−0.00033 (18)
C(5)	0.0144 (3)	0.0146 (3)	0.0135 (2)	0.0022 (2)	0.00165 (19)	−0.0005 (2)
C(6)	0.0127 (2)	0.0124 (2)	0.0126 (2)	0.00072 (18)	0.00231 (18)	−0.00065 (18)
C(1)	0.0127 (3)	0.0135 (3)	0.0122 (2)	0.0016 (2)	0.00261 (18)	0.0009 (2)
H(1)	0.027264	0.028103	0.031217	−0.00293	0.006909	0.004931
H(3)	0.030594	0.033791	0.020333	−0.004102	0.002363	−0.000401
H(5A)	0.021015	0.033998	0.038867	−0.001317	0.007217	−0.003834
H(5B)	0.039948	0.026232	0.025037	0.007188	0.008898	−0.000781
H(2A)	0.029022	0.035374	0.029408	−0.0004	0.002507	−0.005567
H(2B)	0.023545	0.037493	0.032703	0.004348	0.002053	−0.001108
H(4A)	0.029525	0.031256	0.034693	−0.001803	0.004004	−0.001132
H(4B)	0.022893	0.036143	0.033622	0.001431	−0.000934	−0.001598

Geometric parameters (Å, º) top

O(2)—C(2)	1.2292 (11)	N(2)—C(1)	1.3447 (11)
O(4)—C(4)	1.2247 (9)	N(2)—H(2A)	1.0090
O(6)—C(6)	1.2229 (9)	N(2)—H(2B)	1.0090
O(1)—C(1)	1.2649 (10)	N(4)—C(1)	1.3457 (10)
N(1)—C(2)	1.3757 (9)	N(4)—H(4A)	1.0090
N(1)—C(6)	1.3726 (9)	N(4)—H(4B)	1.0090
N(1)—H(1)	1.0090	C(4)—C(5)	1.5043 (9)
N(3)—C(2)	1.3758 (10)	C(5)—C(6)	1.5010 (10)
N(3)—C(4)	1.3729 (9)	C(5)—H(5A)	1.0920
N(3)—H(3)	1.0090	C(5)—H(5B)	1.0920

C(2)—N(1)—C(6)	124.93 (6)	C(4)—C(5)—C(6)	116.35 (6)
C(2)—N(3)—C(4)	125.16 (6)	O(6)—C(6)—N(1)	120.10 (7)
O(2)—C(2)—N(1)	121.04 (7)	O(6)—C(6)—C(5)	122.74 (7)
O(2)—C(2)—N(3)	120.94 (7)	N(1)—C(6)—C(5)	117.15 (6)
N(1)—C(2)—N(3)	118.02 (7)	O(1)—C(1)—N(2)	121.22 (7)
O(4)—C(4)—N(3)	120.70 (7)	O(1)—C(1)—N(4)	121.28 (7)
O(4)—C(4)—C(5)	122.26 (7)	N(2)—C(1)—N(4)	117.49 (7)
N(3)—C(4)—C(5)	117.01 (6)

Experimental details

	(I)	(II)
Crystal data
Chemical formula	C₄H₄N₂O₃·CH₄N₂O	C₄H₄N₂O₃·CH₄N₂O
M_r	188.15	188.15
Crystal system, space group	Monoclinic, P2₁/c	Monoclinic, Cc
Temperature (K)	100	100
a, b, c (Å)	7.8123 (1), 6.9384 (1), 14.1179 (3)	16.0474 (5), 5.0280 (2), 10.3879 (3)
β (°)	96.727 (1)	110.093 (2)
V (Å³)	759.99 (2)	787.15 (5)
Z	4	4
Radiation type	Mo Kα	Mo Kα
µ (mm⁻¹)	0.14	0.14
Crystal size (mm)	0.45 × 0.37 × 0.05	0.35 × 0.32 × 0.15

Data collection
Diffractometer	KappaCCD diffractometer	KappaCCD diffractometer
Absorption correction	Multi-scan HKL DENZO and SCALEPACK (Otwinowski & Minor, 1997)	Multi-scan HKL DENZO and SCALEPACK (Otwinowski & Minor, 1997)
T_min, T_max	0.939, 0.993	0.953, 0.980
No. of measured, independent and observed [ > 2/s(I)] reflections	13521, 7049, 5793	6342, 6342, 5464
R_int	0.029	0.042
(sin θ/λ)_max (Å⁻¹)	1.039	1.116

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.036, 0.029, 1.36	0.038, 0.027, 1.04
No. of reflections	5793	3775
No. of parameters	276	274
H-atom treatment	H-atom parameters constrained	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	?, −0.44	0.30, −0.36

Computer programs: KappaCCD Server Software (Nonius, 1997), DENZO-SMN (Otwinowski & Minor, 1997), HKL DENZO and SCALEPACK (Otwinowski & Minor, 1997), SIR92 (Altomare et al., 1994), Volkov et al., (2006), PLATON (Spek, 2003); ORTEP-3 for Windows (Farrugia, 1997); Mercury (Version 1.4; Macrae et al., 2006).

Selected geometric parameters (Å, º) for (I) top

O(2)—C(2)	1.2250 (4)	N(2)—C(1)	1.3483 (5)
O(4)—C(6)	1.2312 (4)	N(2)—H(2A)	1.0090
O(6)—C(4)	1.2185 (5)	N(2)—H(2B)	1.0090
O(1)—C(1)	1.2601 (4)	N(4)—C(1)	1.3455 (5)
N(1)—C(2)	1.3706 (5)	N(4)—H(4A)	1.0090
N(1)—C(4)	1.3780 (4)	N(4)—H(4B)	1.0090
N(1)—H(1)	1.0090	C(4)—C(5)	1.5023 (5)
N(3)—C(2)	1.3832 (5)	C(5)—C(6)	1.4956 (5)
N(3)—C(6)	1.3634 (5)	C(5)—H(5A)	1.0920
N(3)—H(3)	1.0090	C(5)—H(5B)	1.0920

C(2)—N(1)—C(4)	125.31 (3)	C(4)—C(5)—C(6)	117.17 (3)
C(2)—N(3)—C(6)	124.74 (3)	O(4)—C(6)—N(3)	120.71 (3)
O(2)—C(2)—N(1)	121.74 (3)	O(4)—C(6)—C(5)	121.83 (3)
O(2)—C(2)—N(3)	120.41 (3)	N(3)—C(6)—C(5)	117.45 (3)
N(1)—C(2)—N(3)	117.85 (3)	O(1)—C(1)—N(2)	121.01 (3)
O(6)—C(4)—N(1)	120.95 (3)	O(1)—C(1)—N(4)	120.82 (4)
O(6)—C(4)—C(5)	122.35 (3)	N(2)—C(1)—N(4)	118.17 (3)
N(1)—C(4)—C(5)	116.69 (3)

Selected geometric parameters (Å, º) for (II) top

O(2)—C(2)	1.2292 (11)	N(2)—C(1)	1.3447 (11)
O(4)—C(4)	1.2247 (9)	N(2)—H(2A)	1.0090
O(6)—C(6)	1.2229 (9)	N(2)—H(2B)	1.0090
O(1)—C(1)	1.2649 (10)	N(4)—C(1)	1.3457 (10)
N(1)—C(2)	1.3757 (9)	N(4)—H(4A)	1.0090
N(1)—C(6)	1.3726 (9)	N(4)—H(4B)	1.0090
N(1)—H(1)	1.0090	C(4)—C(5)	1.5043 (9)
N(3)—C(2)	1.3758 (10)	C(5)—C(6)	1.5010 (10)
N(3)—C(4)	1.3729 (9)	C(5)—H(5A)	1.0920
N(3)—H(3)	1.0090	C(5)—H(5B)	1.0920

C(2)—N(1)—C(6)	124.93 (6)	C(4)—C(5)—C(6)	116.35 (6)
C(2)—N(3)—C(4)	125.16 (6)	O(6)—C(6)—N(1)	120.10 (7)
O(2)—C(2)—N(1)	121.04 (7)	O(6)—C(6)—C(5)	122.74 (7)
O(2)—C(2)—N(3)	120.94 (7)	N(1)—C(6)—C(5)	117.15 (6)
N(1)—C(2)—N(3)	118.02 (7)	O(1)—C(1)—N(2)	121.22 (7)
O(4)—C(4)—N(3)	120.70 (7)	O(1)—C(1)—N(4)	121.28 (7)
O(4)—C(4)—C(5)	122.26 (7)	N(2)—C(1)—N(4)	117.49 (7)
N(3)—C(4)—C(5)	117.01 (6)

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