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The structure of the title complex, (C4H12N2)[Cr2O7], consists of dichromate dianions which are connected to the cyclic organic piperazinium (pipH2)2+ dications via hydrogen bonding. There are two crystallographically independent piperazinium dications, both located on centres of inversion, while the anions are located in general positions.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536804021543/bt6511sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536804021543/bt6511Isup2.hkl
Contains datablock I

CCDC reference: 252754

Key indicators

  • Single-crystal X-ray study
  • T = 293 K
  • Mean [sigma](C-C) = 0.003 Å
  • R factor = 0.026
  • wR factor = 0.078
  • Data-to-parameter ratio = 21.2

checkCIF/PLATON results

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Alert level C PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ .... ? PLAT125_ALERT_4_C No _symmetry_space_group_name_Hall Given ....... ? PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X) Cr2 - O7 .. 5.41 su PLAT720_ALERT_4_C Number of Unusual/Non-Standard Label(s) ........ 4 PLAT764_ALERT_4_C Overcomplete CIF Bond List Detected (Rep/Expd) . 1.14 Ratio
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 5 ALERT level C = Check and explain 0 ALERT level G = General alerts; check 1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 1 ALERT type 2 Indicator that the structure model may be wrong or deficient 0 ALERT type 3 Indicator that the structure quality may be low 3 ALERT type 4 Improvement, methodology, query or suggestion

Computing details top

Data collection: DIF4 (Stoe & Cie, 1992); cell refinement: DIF4; data reduction: REDU4 (Stoe & Cie, 1992); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP in SHELXTL (Bruker, 1998); software used to prepare material for publication: CIFTAB in SHELXTL.

Piperazinium dichromate(VI) top
Crystal data top
(C4H12N2)[Cr2O7]F(000) = 616
Mr = 304.16Dx = 2.033 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
a = 11.654 (2) ÅCell parameters from 86 reflections
b = 7.8702 (6) Åθ = 26–38°
c = 10.855 (2) ŵ = 2.21 mm1
β = 93.42 (1)°T = 293 K
V = 993.8 (3) Å3Block, orange
Z = 40.13 × 0.11 × 0.07 mm
Data collection top
Stoe AED-II four-circle
diffractometer
2459 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.033
Graphite monochromatorθmax = 30.0°, θmin = 1.8°
ωθ scansh = 1616
Absorption correction: numerical
(X-SHAPE; Stoe & Cie, 1998)
k = 211
Tmin = 0.755, Tmax = 0.860l = 150
3793 measured reflections4 standard reflections every 120 min
2901 independent reflections intensity decay: none
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.026H-atom parameters constrained
wR(F2) = 0.078 w = 1/[σ2(Fo2) + (0.044P)2 + 0.3618P]
where P = (Fo2 + 2Fc2)/3
S = 1.07(Δ/σ)max = 0.001
2901 reflectionsΔρmax = 0.51 e Å3
137 parametersΔρmin = 0.62 e Å3
0 restraintsExtinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0126 (13)
Special details top

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.

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 > σ(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 (Å2) top
xyzUiso*/Ueq
Cr10.76786 (2)0.49764 (3)0.69306 (2)0.01776 (9)
Cr20.72684 (2)0.57837 (4)0.41834 (2)0.01897 (9)
O10.77675 (14)0.33146 (19)0.77908 (13)0.0319 (3)
O20.88590 (12)0.60764 (19)0.71735 (13)0.0277 (3)
O30.65597 (13)0.6068 (2)0.72271 (13)0.0305 (3)
O40.75442 (12)0.42432 (17)0.53686 (12)0.0246 (3)
O50.81900 (19)0.5539 (2)0.31704 (17)0.0483 (5)
O60.59705 (15)0.5528 (2)0.35954 (15)0.0374 (4)
O70.73990 (12)0.76513 (17)0.48130 (12)0.0262 (3)
N10.96670 (13)0.9161 (2)0.60951 (13)0.0215 (3)
H1N10.91850.84790.64830.026*
H2N11.02240.94980.66510.026*
C11.01935 (15)0.8183 (2)0.50881 (17)0.0231 (3)
H1A0.95920.77340.45240.028*
H1B1.06310.72340.54410.028*
C20.90256 (15)1.0674 (2)0.56055 (17)0.0224 (3)
H2A0.87201.12990.62830.027*
H2B0.83851.03100.50580.027*
N20.56364 (15)0.5708 (2)0.10427 (15)0.0264 (3)
H1N20.62370.61820.06870.032*
H2N20.57250.58980.18600.032*
C30.56324 (17)0.3850 (2)0.08107 (18)0.0278 (4)
H3A0.50260.33230.12510.033*
H3B0.63600.33680.11200.033*
C40.45517 (17)0.6525 (2)0.05457 (19)0.0288 (4)
H4A0.45960.77430.06740.035*
H4B0.39080.60940.09790.035*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cr10.02122 (14)0.01581 (14)0.01630 (13)0.00043 (10)0.00146 (9)0.00036 (9)
Cr20.02653 (15)0.01550 (13)0.01526 (13)0.00336 (10)0.00430 (9)0.00083 (10)
O10.0462 (8)0.0231 (7)0.0266 (6)0.0006 (6)0.0026 (6)0.0075 (6)
O20.0267 (6)0.0279 (7)0.0283 (6)0.0062 (5)0.0016 (5)0.0010 (5)
O30.0306 (7)0.0324 (8)0.0291 (6)0.0082 (6)0.0062 (5)0.0027 (6)
O40.0364 (7)0.0180 (6)0.0192 (5)0.0026 (5)0.0005 (5)0.0014 (5)
O50.0747 (13)0.0284 (8)0.0462 (9)0.0001 (8)0.0410 (9)0.0011 (7)
O60.0428 (9)0.0305 (8)0.0366 (8)0.0120 (7)0.0157 (7)0.0072 (6)
O70.0303 (7)0.0194 (6)0.0290 (6)0.0030 (5)0.0030 (5)0.0039 (5)
N10.0230 (7)0.0227 (7)0.0192 (6)0.0044 (6)0.0049 (5)0.0028 (5)
C10.0247 (8)0.0177 (8)0.0272 (8)0.0019 (6)0.0053 (6)0.0007 (6)
C20.0197 (7)0.0218 (8)0.0265 (8)0.0002 (6)0.0069 (6)0.0020 (7)
N20.0303 (8)0.0249 (8)0.0238 (7)0.0050 (6)0.0000 (6)0.0037 (6)
C30.0290 (9)0.0217 (8)0.0327 (9)0.0019 (7)0.0004 (7)0.0067 (7)
C40.0309 (9)0.0205 (8)0.0358 (9)0.0039 (7)0.0096 (7)0.0052 (8)
Geometric parameters (Å, º) top
Cr1—O11.6068 (14)C1—H1B0.9700
Cr1—O31.6101 (14)C2—C1i1.512 (2)
Cr1—O21.6334 (14)C2—H2A0.9700
Cr1—O41.7890 (13)C2—H2B0.9700
Cr2—O51.5939 (16)N2—C31.484 (3)
Cr2—O61.6189 (16)N2—C41.490 (3)
Cr2—O71.6242 (14)N2—H1N20.9000
Cr2—O41.7830 (13)N2—H2N20.9000
N1—C21.487 (2)C3—C4ii1.504 (3)
N1—C11.498 (2)C3—H3A0.9700
N1—H1N10.9000C3—H3B0.9700
N1—H2N10.9000C4—C3ii1.504 (3)
C1—C2i1.512 (2)C4—H4A0.9700
C1—H1A0.9700C4—H4B0.9700
O1—Cr1—O3110.06 (8)N1—C2—C1i110.47 (14)
O1—Cr1—O2108.25 (8)N1—C2—H2A109.6
O3—Cr1—O2111.67 (8)C1i—C2—H2A109.6
O1—Cr1—O4106.69 (7)N1—C2—H2B109.6
O3—Cr1—O4109.60 (7)C1i—C2—H2B109.6
O2—Cr1—O4110.44 (7)H2A—C2—H2B108.1
O5—Cr2—O6111.42 (11)C3—N2—C4111.69 (15)
O5—Cr2—O7110.45 (8)C3—N2—H1N2109.3
O6—Cr2—O7109.88 (8)C4—N2—H1N2109.3
O5—Cr2—O4108.41 (9)C3—N2—H2N2109.3
O6—Cr2—O4108.91 (7)C4—N2—H2N2109.3
O7—Cr2—O4107.67 (7)H1N2—N2—H2N2107.9
Cr2—O4—Cr1117.79 (7)N2—C3—C4ii110.97 (15)
C2—N1—C1111.69 (13)N2—C3—H3A109.4
C2—N1—H1N1109.3C4ii—C3—H3A109.4
C1—N1—H1N1109.3N2—C3—H3B109.4
C2—N1—H2N1109.3C4ii—C3—H3B109.4
C1—N1—H2N1109.3H3A—C3—H3B108.0
H1N1—N1—H2N1107.9N2—C4—C3ii109.77 (15)
N1—C1—C2i110.06 (14)N2—C4—H4A109.7
N1—C1—H1A109.6C3ii—C4—H4A109.7
C2i—C1—H1A109.6N2—C4—H4B109.7
N1—C1—H1B109.6C3ii—C4—H4B109.7
C2i—C1—H1B109.6H4A—C4—H4B108.2
H1A—C1—H1B108.2
Symmetry codes: (i) x+2, y+2, z+1; (ii) x+1, y+1, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1N1···O20.902.082.878 (2)148
N1—H1N1···O5iii0.902.362.925 (2)121
N1—H2N1···O2iv0.902.042.893 (2)159
N1—H2N1···O1iv0.902.563.227 (2)132
N2—H1N2···O7v0.901.932.828 (2)174
N2—H2N2···O60.901.912.779 (2)162
Symmetry codes: (iii) x, y+3/2, z+1/2; (iv) x+2, y+1/2, z+3/2; (v) x, y+3/2, z1/2.
 

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