The XIPHOS diffraction facility for extreme sample conditions

XIPHOS has been developed to expand home laboratory facilities closer to those found at central facilities, offering extremes of sample environment and flux densities far greater than standard laboratory sources. The system has a minimum operating temperature of 1.9 K, and has a direct-drive molybdenum rotating-anode generator coupled with the latest multilayer optics. XIPHOS has been specifically designed to accommodate various sample environments and is now operational. Furthermore, it has been calibrated with structural phase transitions from 14 to 148 K. Results are also presented from a full low-temperature data collection of m-nitroaniline to demonstrate the quality of results attainable from XIPHOS.

Computing details

Data collection: Bruker APEXII v2010.1-2 (Bruker, 2010); cell refinement: Bruker SAINT version 7.68a (Bruker, 2010); data reduction: Bruker SAINT version 7.68a (Bruker, 2010); program(s) used to solve structure: A short history of SHELX (Sheldrick, 2007)/Bruker; program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: OLEX2: a complete structure solution, refinement and analysis program. Dolomanov et al., J. Appl. Cryst. (2009). 42, 339-341; software used to prepare material for publication: OLEX2: a complete structure solution, refinement and analysis program. Dolomanov et al., J. Appl. Cryst. (2009). 42, 339-341.

m-nitroaniline

Crystal data

C6H6N2O2	Dx = 1.503 Mg m^−3
Mr = 138.13	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pca21	Cell parameters from 3128 reflections
a = 18.7169 (4) Å	θ = 3.3–30.4°
b = 6.5215 (2) Å	µ = 0.12 mm^−1
c = 5.0014 (1) Å	T = 2 K
V = 610.48 (3) Å^3	Block, clear yellowish yellow
Z = 4	0.27 × 0.1 × 0.08 mm
F(000) = 288

Data collection

Bruker APEX-II CCD diffractometer	993 independent reflections
Radiation source: Bruker TXS with Helios Optics	935 reflections with I > 2σ(I)
Multilayer optics monochromator	Rint = 0.034
φ and ω scans	θmax = 30.4°, θmin = 2.2°
Absorption correction: multi-scan SADABS-2008/1 (Bruker,2008) was used for absorption correction. R(int) was 0.0670 before and 0.0419 after correction. The Ratio of minimum to maximum transmission is 0.818632707775. The λ/2 correction factor is Not present	h = −26→26
Tmin = 0.611, Tmax = 0.746	k = −9→9
9614 measured reflections	l = −7→7

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.033	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.088	w = 1/[σ^2(Fo^2) + (0.0542P)^2 + 0.2014P] where P = (Fo^2 + 2Fc^2)/3
S = 1.07	(Δ/σ)max < 0.001
993 reflections	Δρmax = 0.33 e Å^−3
115 parameters	Δρmin = −0.22 e Å^−3
1 restraint	Absolute structure: not refined as all light atom structure
Primary atom site location: structure-invariant direct methods

Special details

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

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > 2sigma(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	Uiso*/Ueq
O1	0.39879 (6)	1.06784 (19)	0.0795 (3)	0.0132 (3)
O2	0.30390 (6)	0.89456 (19)	−0.0261 (3)	0.0124 (3)
N1	0.30431 (7)	0.2819 (2)	0.5743 (3)	0.0106 (3)
N2	0.35802 (7)	0.9202 (2)	0.1096 (3)	0.0092 (3)
C5	0.37561 (8)	0.7694 (2)	0.3170 (3)	0.0084 (3)
C6	0.33173 (9)	0.5977 (2)	0.3415 (3)	0.0092 (3)
C1	0.34867 (8)	0.4516 (2)	0.5354 (3)	0.0089 (3)
C2	0.40898 (8)	0.4832 (3)	0.6982 (3)	0.0101 (3)
C3	0.45130 (8)	0.6569 (3)	0.6668 (3)	0.0102 (3)
C4	0.43576 (8)	0.8043 (3)	0.4746 (4)	0.0097 (3)
H6	0.2909 (12)	0.582 (4)	0.229 (6)	0.015 (6)*
H4	0.4634 (12)	0.926 (4)	0.460 (7)	0.018 (6)*
H2	0.4188 (14)	0.387 (4)	0.827 (7)	0.020 (6)*
H1A	0.2771 (11)	0.259 (3)	0.448 (6)	0.009 (5)*
H3	0.4923 (12)	0.677 (3)	0.779 (5)	0.011 (6)*
H1B	0.3231 (12)	0.176 (4)	0.657 (6)	0.015 (6)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0141 (6)	0.0090 (5)	0.0164 (6)	−0.0029 (4)	−0.0003 (5)	0.0024 (5)
O2	0.0119 (5)	0.0120 (6)	0.0133 (6)	0.0000 (4)	−0.0029 (5)	0.0018 (5)
N1	0.0108 (6)	0.0089 (6)	0.0121 (6)	−0.0017 (5)	−0.0018 (6)	0.0019 (6)
N2	0.0099 (6)	0.0078 (6)	0.0097 (6)	0.0010 (4)	0.0007 (6)	0.0000 (5)
C5	0.0098 (7)	0.0068 (7)	0.0086 (6)	0.0019 (5)	−0.0002 (6)	0.0010 (6)
C6	0.0093 (7)	0.0081 (7)	0.0101 (6)	−0.0002 (5)	0.0004 (6)	−0.0014 (6)
C1	0.0093 (6)	0.0081 (7)	0.0094 (7)	0.0011 (5)	0.0025 (5)	−0.0003 (6)
C2	0.0104 (7)	0.0093 (7)	0.0104 (7)	0.0005 (6)	0.0007 (6)	0.0019 (6)
C3	0.0090 (6)	0.0109 (7)	0.0109 (7)	0.0000 (5)	−0.0012 (6)	0.0003 (6)
C4	0.0104 (6)	0.0076 (6)	0.0111 (7)	−0.0015 (5)	0.0004 (6)	0.0001 (6)

Geometric parameters (Å, º)

O1—N2	1.2379 (17)	C6—C1	1.396 (2)
O2—N2	1.2307 (18)	C6—H6	0.96 (3)
N1—C1	1.397 (2)	C1—C2	1.407 (2)
N1—H1A	0.83 (3)	C2—C3	1.391 (2)
N1—H1B	0.88 (3)	C2—H2	0.92 (3)
N2—C5	1.466 (2)	C3—C4	1.390 (2)
C5—C6	1.394 (2)	C3—H3	0.96 (2)
C5—C4	1.393 (2)	C4—H4	0.95 (2)
O1—N2—C5	117.99 (13)	C1—C6—H6	121.2 (16)
O2—N2—O1	123.07 (14)	C1—C2—H2	117.7 (17)
O2—N2—C5	118.94 (13)	C2—C3—H3	119.9 (14)
N1—C1—C2	120.82 (15)	C3—C2—C1	120.73 (15)
C5—C6—C1	118.41 (15)	C3—C2—H2	121.5 (17)
C5—C6—H6	120.4 (16)	C3—C4—C5	116.59 (14)
C5—C4—H4	122.2 (18)	C3—C4—H4	121.1 (18)
C6—C5—N2	117.94 (14)	C4—C5—N2	118.18 (14)
C6—C1—N1	120.18 (14)	C4—C5—C6	123.88 (15)
C6—C1—C2	118.94 (15)	C4—C3—C2	121.46 (15)
C1—N1—H1A	113.7 (16)	C4—C3—H3	118.7 (14)
C1—N1—H1B	116.8 (15)	H1A—N1—H1B	118 (2)
O1—N2—C5—C6	−176.72 (14)	C5—C6—C1—N1	177.17 (14)
O1—N2—C5—C4	2.2 (2)	C5—C6—C1—C2	0.1 (2)
O2—N2—C5—C6	3.2 (2)	C6—C5—C4—C3	−0.3 (2)
O2—N2—C5—C4	−177.92 (15)	C6—C1—C2—C3	−0.2 (2)
N1—C1—C2—C3	−177.16 (15)	C1—C2—C3—C4	−0.1 (3)
N2—C5—C6—C1	178.97 (15)	C2—C3—C4—C5	0.3 (2)
N2—C5—C4—C3	−179.20 (15)	C4—C5—C6—C1	0.1 (2)