Bis­[di­carbonyl­(cyclo­penta­dienyl)­ferrio]­mercury(II)

Crystals of Hg[Fe(CO)₂(η⁵–C₅H₅)]₂ contain discrete mol­ecules with crystallographically imposed twofold symmetry, Hg—Fe 2.5546 (10) Å and an Fe—Hg—Fe angle of 156.34 (6)°, the most acute yet found for a simple Hg[ML_n]₂ species.

Key indicators

• Single-crystal X-ray study
• T = 203 K
• Mean [sigma](C-C) = 0.014 Å
• R factor = 0.037
• wR factor = 0.100
• Data-to-parameter ratio = 17.8

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level A:



ABSTM_02  Alert A Crystal and compound unsuitable for non-numerical
          corrections. Product of mu and tmid > 3.0
           Value of mu given =    12.705 tmid =     0.480

Author response: Absorption correction with SADABS appeared to give a satisfactory correction.

General Notes



REFLT_03
         From the CIF: _diffrn_reflns_theta_max           28.30
         From the CIF: _reflns_number_total               1726
         Count of symmetry unique reflns         1070
         Completeness (_total/calc)            161.31%
         TEST3: Check Friedels for noncentro structure
         Estimate of Friedel pairs measured       656
         Fraction of Friedel pairs measured     0.613
         Are heavy atom types Z>Si present          yes
          Please check that the estimate of the number of Friedel pairs is
          correct. If it is not, please give the correct count in the
          _publ_section_exptl_refinement section of the submitted CIF.


 1 Alert Level A = Potentially serious problem

 0 Alert Level B = Potential problem

 0 Alert Level C = Please check

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Computing details

Data collection: SMART (Siemens, 1994); cell refinement: SAINT (Siemens, 1994); data reduction: SADABS (Blessing, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Bis[cyclopentadienyl(dicarbonyl)iron]mercury(II)

Crystal data

[HgFe2(C5H5)2(CO)4]	Dx = 2.572 Mg m^−3
Mr = 554.51	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P43212	Cell parameters from 1726 reflections
a = 11.6756 (1) Å	θ = 2–28°
c = 10.5030 (1) Å	µ = 12.71 mm^−1
V = 1431.77 (2) Å^3	T = 203 K
Z = 4	Prism, brown
F(000) = 1032	0.58 × 0.48 × 0.36 mm

Data collection

Siemens SMART CCD diffractometer	1726 independent reflections
Radiation source: fine-focus sealed tube	1687 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.029
multi–scan	θmax = 28.3°, θmin = 2.5°
Absorption correction: empirical (using intensity measurements) (Blessing, 1995)	h = −15→15
Tmin = 0.003, Tmax = 0.011	k = 0→15
3323 measured reflections	l = 0→13

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.100	H-atom parameters constrained
S = 1.09	w = 1/[σ^2(Fo^2) + (0.034P)^2 + 16.5365P] where P = (Fo^2 + 2Fc^2)/3
1726 reflections	(Δ/σ)max < 0.001
97 parameters	Δρmax = 1.72 e Å^−3
0 restraints	Δρmin = −2.49 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.

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 (Ų)

	x	y	z	Uiso*/Ueq
Hg1	0.24290 (2)	0.24290 (2)	0.0000	0.02149 (14)
Fe1	0.28631 (9)	0.26284 (8)	0.23736 (10)	0.0163 (2)
O1	0.0939 (6)	0.1212 (7)	0.3137 (7)	0.0350 (18)
O2	0.1532 (7)	0.4720 (6)	0.2192 (8)	0.0394 (18)
C1	0.1683 (7)	0.1758 (8)	0.2800 (7)	0.0224 (16)
C2	0.2057 (8)	0.3893 (7)	0.2223 (8)	0.0227 (17)
C11	0.4212 (8)	0.3354 (8)	0.3394 (9)	0.0252 (19)
H11	0.4171	0.4043	0.3855	0.030*
C12	0.4516 (9)	0.3252 (9)	0.2082 (9)	0.028 (2)
H12	0.4692	0.3858	0.1526	0.033*
C13	0.4505 (8)	0.2069 (10)	0.1772 (10)	0.029 (2)
H13	0.4691	0.1743	0.0981	0.035*
C14	0.4158 (8)	0.1469 (9)	0.2888 (8)	0.026 (2)
H14	0.4061	0.0672	0.2954	0.031*
C15	0.3984 (8)	0.2269 (9)	0.3880 (8)	0.0263 (19)
H15	0.3756	0.2098	0.4717	0.032*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Hg1	0.02664 (17)	0.02664 (17)	0.0112 (2)	0.00052 (16)	−0.00007 (10)	0.00007 (10)
Fe1	0.0168 (5)	0.0190 (5)	0.0132 (5)	−0.0003 (4)	−0.0001 (4)	−0.0013 (4)
O1	0.033 (4)	0.041 (5)	0.031 (4)	−0.010 (3)	0.008 (3)	0.005 (3)
O2	0.041 (4)	0.032 (4)	0.045 (5)	0.012 (3)	−0.001 (3)	−0.003 (3)
C1	0.023 (4)	0.028 (4)	0.016 (4)	0.000 (3)	−0.002 (3)	0.005 (3)
C2	0.028 (4)	0.021 (4)	0.019 (4)	−0.001 (3)	−0.002 (3)	−0.004 (3)
C11	0.025 (5)	0.029 (5)	0.022 (4)	−0.001 (4)	−0.006 (4)	−0.007 (4)
C12	0.023 (4)	0.034 (5)	0.027 (5)	−0.006 (4)	0.001 (4)	0.000 (4)
C13	0.015 (4)	0.042 (6)	0.030 (5)	0.005 (4)	0.006 (3)	0.002 (4)
C14	0.026 (4)	0.031 (5)	0.021 (4)	0.007 (4)	−0.007 (3)	0.000 (3)
C15	0.027 (4)	0.037 (5)	0.015 (4)	0.004 (4)	−0.008 (3)	0.000 (4)

Geometric parameters (Å, º)

Hg1—Fe1	2.5546 (10)	Fe1—C13	2.121 (9)
Hg1—Fe1^i	2.5546 (10)	O1—C1	1.135 (10)
Fe1—C2	1.758 (9)	O2—C2	1.144 (11)
Fe1—C1	1.769 (8)	C11—C15	1.391 (14)
Fe1—C12	2.085 (10)	C11—C12	1.428 (13)
Fe1—C11	2.085 (9)	C12—C13	1.419 (15)
Fe1—C15	2.096 (8)	C13—C14	1.424 (14)
Fe1—C14	2.100 (9)	C14—C15	1.413 (13)
Fe1—Hg1—Fe1^i	156.37 (5)	C1—Fe1—Hg1	92.3 (3)
C2—Fe1—C1	95.0 (4)	C12—Fe1—Hg1	94.1 (3)
C2—Fe1—C12	100.9 (4)	C11—Fe1—Hg1	133.5 (3)
C1—Fe1—C12	163.4 (4)	C15—Fe1—Hg1	147.4 (3)
C2—Fe1—C11	96.3 (4)	C14—Fe1—Hg1	109.6 (3)
C1—Fe1—C11	133.7 (4)	C13—Fe1—Hg1	82.0 (3)
C12—Fe1—C11	40.0 (4)	O1—C1—Fe1	176.5 (8)
C2—Fe1—C15	124.8 (4)	O2—C2—Fe1	176.5 (8)
C1—Fe1—C15	100.4 (4)	C15—C11—C12	109.0 (9)
C12—Fe1—C15	66.6 (4)	C15—C11—Fe1	71.0 (5)
C11—Fe1—C15	38.9 (4)	C12—C11—Fe1	70.0 (6)
C2—Fe1—C14	161.8 (4)	C13—C12—C11	107.5 (9)
C1—Fe1—C14	97.2 (4)	C13—C12—Fe1	71.7 (6)
C12—Fe1—C14	66.2 (4)	C11—C12—Fe1	69.9 (6)
C11—Fe1—C14	65.5 (4)	C12—C13—C14	107.0 (9)
C15—Fe1—C14	39.4 (4)	C12—C13—Fe1	68.9 (6)
C2—Fe1—C13	135.7 (4)	C14—C13—Fe1	69.5 (5)
C1—Fe1—C13	127.0 (4)	C15—C14—C13	108.8 (9)
C12—Fe1—C13	39.4 (4)	C15—C14—Fe1	70.2 (5)
C11—Fe1—C13	66.1 (4)	C13—C14—Fe1	71.1 (6)
C15—Fe1—C13	66.3 (4)	C11—C15—C14	107.7 (8)
C14—Fe1—C13	39.4 (4)	C11—C15—Fe1	70.1 (5)
C2—Fe1—Hg1	83.3 (3)	C14—C15—Fe1	70.5 (5)

Symmetry code: (i) y, x, −z.