XPAD X-ray hybrid pixel detector for charge density quality diffracted intensities on laboratory equipment

The new generation of X-ray detectors, the hybrid pixel area detectors or `pixel detectors', is based on direct detection and single-photon counting processes. A large linearity range, high dynamic and extremely low noise leading to an unprecedented high signal-to-noise ratio, fast readout time (high frame rates) and an electronic shutter are among their intrinsic characteristics which render them very attractive. First used on synchrotron beamlines, these detectors are also promising in the laboratory, in particular for pump-probe or quasi-static experiments and accurate electron density measurements, as explained in this paper. An original laboratory diffractometer made from a Nonius Mach3 goniometer equipped with an Incoatec Mo microsource and an XPAD pixel area detector has been developed at the CRM2 laboratory. Mo Kα accurate charge density quality data up to 1.21 Å⁻¹ resolution have been collected on a sodium nitroprusside crystal using this home-made diffractometer. Data quality for charge density analysis based on multipolar modelling are discussed in this paper. Deformation electron densities are compared to those already published (based on data collected with CCD APEXII and CAD4 diffractometers).

Computing details

Data collection: CAD4, Bruker-Nonius; cell refinement: CrysAlis PRO, Agilent Technologies, Version 1.171.37.31 (release 14-01-2014 CrysAlis171 .NET) (compiled Jan 14 2014,18:38:05); data reduction: CrysAlis PRO, Agilent Technologies, Version 1.171.37.31 (release 14-01-2014 CrysAlis171 .NET) (compiled Jan 14 2014,18:38:05); program(s) used to solve structure: SIR92; program(s) used to refine structure: SHELXL2013 (Sheldrick, 2013); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: ShelXle, C. B. Hubschle, G. M. Sheldrick and B. Dittrich.

Figures

(I)

Crystal data

C5H4FeN6Na2O3	Dx = 1.750 Mg m^−3
Mr = 297.97	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pnnm	Cell parameters from 213934 reflections
a = 6.14102 (7) Å	θ = 2.2–59.4°
b = 11.84510 (16) Å	µ = 1.41 mm^−1
c = 15.5509 (3) Å	T = 100 K
V = 1131.19 (3) Å^3	Prismatic, red
Z = 4	0.22 × 0.19 × 0.17 mm
F(000) = 592

Data collection

Pixel detector XPAD 3.2 diffractometer	6059 reflections with I > 2σ(I)
ω scans	Rint = 0.034
Absorption correction: multi-scan CrysAlis PRO, Agilent Technologies, Version 1.171.36.32 (release 02-08-2013 CrysAlis171 .NET) (compiled Aug 2 2013,16:46:58) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.	θmax = 59.4°, θmin = 2.2°
Tmin = 0.741, Tmax = 0.785	h = 0→14
213934 measured reflections	k = 0→28
8273 independent reflections	l = 0→37

Refinement

Refinement on F^2	3 restraints
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.025	All H-atom parameters refined
wR(F^2) = 0.062	w = 1/[σ^2(Fo^2)] where P = (Fo^2 + 2Fc^2)/3
S = 0.90	(Δ/σ)max = 0.001
8273 reflections	Δρmax = 0.97 e Å^−3
95 parameters	Δρmin = −1.15 e Å^−3

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

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

	x	y	z	Uiso*/Ueq
Fe	0.50052 (2)	0.28023 (2)	0.5000	0.006290 (10)
N4	0.72604 (9)	0.35805 (5)	0.5000	0.00934 (7)
O	0.88629 (11)	0.40525 (6)	0.5000	0.01922 (11)
C1	0.25010 (11)	0.18273 (6)	0.5000	0.01001 (8)
N1	0.10007 (11)	0.12369 (6)	0.5000	0.01481 (10)
C2	0.60742 (8)	0.17946 (4)	0.58803 (3)	0.00994 (6)
N2	0.66722 (8)	0.11964 (4)	0.64187 (3)	0.01474 (7)
C3	0.34548 (8)	0.36188 (4)	0.41087 (3)	0.01034 (6)
N3	0.25007 (9)	0.40533 (5)	0.35576 (3)	0.01647 (8)
Na1	0.5000	0.0000	0.24581 (2)	0.01106 (4)
Na2	0.0000	0.0000	0.37803 (2)	0.01295 (5)
OW1	0.17207 (8)	0.12262 (4)	0.26871 (3)	0.01659 (7)
H1	0.1810 (19)	0.1885 (9)	0.2867 (7)	0.048 (3)*
H2	0.061 (2)	0.1216 (11)	0.2352 (7)	0.060 (4)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Fe	0.00623 (2)	0.00685 (2)	0.00578 (2)	−0.00032 (3)	0.000	0.000
N4	0.00840 (16)	0.00878 (16)	0.01084 (17)	−0.00104 (13)	0.000	0.000
O	0.0119 (2)	0.0174 (2)	0.0284 (3)	−0.00698 (18)	0.000	0.000
C1	0.00975 (19)	0.0106 (2)	0.00964 (18)	−0.00186 (17)	0.000	0.000
N1	0.0129 (2)	0.0152 (2)	0.0164 (2)	−0.00550 (19)	0.000	0.000
C2	0.00949 (13)	0.01097 (14)	0.00936 (13)	0.00046 (11)	0.00012 (11)	0.00144 (11)
N2	0.01433 (16)	0.01660 (16)	0.01328 (15)	0.00205 (14)	−0.00008 (13)	0.00578 (13)
C3	0.01007 (13)	0.01224 (14)	0.00871 (13)	0.00117 (12)	0.00002 (11)	0.00114 (11)
N3	0.01589 (17)	0.0215 (2)	0.01200 (14)	0.00383 (15)	−0.00158 (13)	0.00469 (14)
Na1	0.01141 (11)	0.01263 (11)	0.00914 (9)	−0.00228 (10)	0.000	0.000
Na2	0.01227 (11)	0.01454 (12)	0.01205 (11)	0.00094 (11)	0.000	0.000
OW1	0.01604 (16)	0.01664 (16)	0.01708 (15)	0.00135 (13)	−0.00245 (13)	0.00190 (13)

Geometric parameters (Å, º)

Fe—N4	1.6636 (6)	Na1—N2^i	2.4726 (5)
Fe—C1	1.9232 (7)	Na1—N2^iii	2.4726 (5)
Fe—C2	1.9312 (5)	Na1—OW1	2.5084 (5)
Fe—C2^i	1.9312 (5)	Na1—OW1^vii	2.5084 (5)
Fe—C3	1.9399 (5)	Na1—Na2^viii	3.6954 (3)
Fe—C3^i	1.9400 (5)	Na1—Na2	3.6954 (3)
N4—O	1.1319 (8)	Na2—OW1	2.4731 (5)
C1—N1	1.1567 (9)	Na2—OW1^ix	2.4732 (5)
N1—Na2	2.4742 (5)	Na2—N1^ii	2.4743 (5)
N1—Na2^ii	2.4743 (5)	Na2—N2^x	2.5061 (5)
C2—N2	1.1567 (6)	Na2—N2^iii	2.5061 (5)
N2—Na1^iii	2.4727 (5)	Na2—Na1^xi	3.6954 (3)
N2—Na2^iii	2.5061 (5)	Na2—Na2^ii	3.7935 (7)
C3—N3	1.1586 (6)	Na2—H2	2.673 (12)
N3—Na1^iv	2.4720 (5)	OW1—H1	0.831 (11)
Na1—N3^v	2.4720 (5)	OW1—H2	0.858 (12)
Na1—N3^vi	2.4720 (5)
N4—Fe—C1	176.74 (3)	Na2^viii—Na1—Na2	112.382 (12)
N4—Fe—C2	93.41 (2)	OW1—Na2—OW1^ix	93.15 (3)
C1—Fe—C2	84.30 (2)	OW1—Na2—N1	94.190 (16)
N4—Fe—C2^i	93.41 (2)	OW1^ix—Na2—N1	168.770 (19)
C1—Fe—C2^i	84.30 (2)	OW1—Na2—N1^ii	168.770 (19)
C2—Fe—C2^i	90.28 (3)	OW1^ix—Na2—N1^ii	94.189 (16)
N4—Fe—C3	97.60 (2)	N1—Na2—N1^ii	79.90 (3)
C1—Fe—C3	84.66 (2)	OW1—Na2—N2^x	86.067 (17)
C2—Fe—C3	168.95 (2)	OW1^ix—Na2—N2^x	84.193 (16)
C2^i—Fe—C3	88.20 (2)	N1—Na2—N2^x	87.84 (2)
N4—Fe—C3^i	97.60 (2)	N1^ii—Na2—N2^x	103.12 (2)
C1—Fe—C3^i	84.66 (2)	OW1—Na2—N2^iii	84.192 (16)
C2—Fe—C3^i	88.20 (2)	OW1^ix—Na2—N2^iii	86.067 (17)
C2^i—Fe—C3^i	168.95 (2)	N1—Na2—N2^iii	103.12 (2)
C3—Fe—C3^i	91.21 (3)	N1^ii—Na2—N2^iii	87.84 (2)
O—N4—Fe	175.96 (6)	N2^x—Na2—N2^iii	165.81 (3)
N1—C1—Fe	179.70 (7)	OW1—Na2—Na1	42.482 (11)
C1—N1—Na2	123.77 (3)	OW1^ix—Na2—Na1	88.424 (14)
C1—N1—Na2^ii	123.77 (3)	N1—Na2—Na1	102.720 (15)
Na2—N1—Na2^ii	100.10 (3)	N1^ii—Na2—Na1	129.265 (18)
N2—C2—Fe	178.42 (5)	N2^x—Na2—Na1	127.507 (15)
C2—N2—Na1^iii	136.94 (4)	N2^iii—Na2—Na1	41.731 (11)
C2—N2—Na2^iii	121.06 (4)	OW1—Na2—Na1^xi	88.425 (14)
Na1^iii—N2—Na2^iii	95.843 (16)	OW1^ix—Na2—Na1^xi	42.482 (11)
N3—C3—Fe	176.46 (5)	N1—Na2—Na1^xi	129.266 (18)
C3—N3—Na1^iv	171.19 (4)	N1^ii—Na2—Na1^xi	102.720 (15)
N3^v—Na1—N3^vi	100.57 (3)	N2^x—Na2—Na1^xi	41.731 (11)
N3^v—Na1—N2^i	165.785 (17)	N2^iii—Na2—Na1^xi	127.507 (15)
N3^vi—Na1—N2^i	86.181 (17)	Na1—Na2—Na1^xi	112.382 (12)
N3^v—Na1—N2^iii	86.181 (17)	OW1—Na2—Na2^ii	133.425 (13)
N3^vi—Na1—N2^iii	165.785 (17)	OW1^ix—Na2—Na2^ii	133.425 (13)
N2^i—Na1—N2^iii	90.11 (3)	N1—Na2—Na2^ii	39.951 (13)
N3^v—Na1—OW1	81.643 (17)	N1^ii—Na2—Na2^ii	39.952 (13)
N3^vi—Na1—OW1	109.075 (18)	N2^x—Na2—Na2^ii	97.093 (13)
N2^i—Na1—OW1	84.333 (17)	N2^iii—Na2—Na2^ii	97.093 (13)
N2^iii—Na1—OW1	84.153 (16)	Na1—Na2—Na2^ii	123.809 (6)
N3^v—Na1—OW1^vii	109.074 (18)	Na1^xi—Na2—Na2^ii	123.809 (6)
N3^vi—Na1—OW1^vii	81.643 (17)	OW1—Na2—H2	18.7 (3)
N2^i—Na1—OW1^vii	84.154 (16)	OW1^ix—Na2—H2	78.8 (3)
N2^iii—Na1—OW1^vii	84.333 (17)	N1—Na2—H2	106.4 (3)
OW1—Na1—OW1^vii	163.67 (3)	N1^ii—Na2—H2	172.2 (3)
N3^v—Na1—Na2^viii	150.659 (13)	N2^x—Na2—H2	73.0 (3)
N3^vi—Na1—Na2^viii	80.755 (13)	N2^iii—Na2—H2	95.0 (3)
N2^i—Na1—Na2^viii	42.425 (12)	Na1—Na2—H2	54.6 (3)
N2^iii—Na1—Na2^viii	87.249 (14)	Na1^xi—Na2—H2	69.8 (3)
OW1—Na1—Na2^viii	126.020 (14)	Na2^ii—Na2—H2	146.2 (3)
OW1^vii—Na1—Na2^viii	41.749 (11)	Na2—OW1—Na1	95.771 (16)
N3^v—Na1—Na2	80.755 (13)	Na2—OW1—H1	110.4 (8)
N3^vi—Na1—Na2	150.659 (13)	Na1—OW1—H1	122.6 (8)
N2^i—Na1—Na2	87.248 (14)	Na2—OW1—H2	94.0 (8)
N2^iii—Na1—Na2	42.425 (12)	Na1—OW1—H2	122.9 (8)
OW1—Na1—Na2	41.748 (11)	H1—OW1—H2	105.7 (11)
OW1^vii—Na1—Na2	126.020 (14)

Symmetry codes: (i) x, y, −z+1; (ii) −x, −y, −z+1; (iii) −x+1, −y, −z+1; (iv) x−1/2, −y+1/2, −z+1/2; (v) −x+1/2, y−1/2, −z+1/2; (vi) x+1/2, −y+1/2, −z+1/2; (vii) −x+1, −y, z; (viii) x+1, y, z; (ix) −x, −y, z; (x) x−1, y, −z+1; (xi) x−1, y, z.