Disodium tetra­aqua­bis(sulfato)iron(II)

In the title compound, [FeNa₂(SO₄)₂(H₂O)₄], the Fe²⁺ cation is situated on a centre of inversion and is hexa­coordinated by four O atoms from water mol­ecules and two O atoms from two sulfate anions in an octa­hedral geometry. The coordination environment of Na⁺ comprises six O atoms in a more distorted octa­hedral arrangement, with Na—O distances between 2.368 (1) and 2.612 (1) Å. The structure contains an extensive three-dimensional network of O—H...O hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 301 K
• Mean [sigma](Fe-O) = 0.001 Å
• R factor = 0.018
• wR factor = 0.048
• Data-to-parameter ratio = 14.0

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low .......       0.96
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT150_ALERT_1_C Volume as Calculated Differs from that Given ...     503.10 Ang-3
PLAT152_ALERT_1_C Supplied and Calc Volume s.u. Inconsistent .....          ?
PLAT153_ALERT_1_C The su's on the Cell Axes   are Equal (x 100000)        100 Ang.
PLAT180_ALERT_3_C Check Cell Rounding: # of Values Ending with 0 =          4
PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X)  Fe1    -   O8      ..       5.30 su

Alert level G
ABSTM02_ALERT_3_G  The ratio of expected to reported Tmax/Tmin(RR) is > 1.10
            Tmin and Tmax reported:      0.398     0.720
            Tmin and Tmax expected:      0.349     0.705
            RR =      1.117
            Please check that your absorption correction is appropriate.

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   7 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   4 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
   3 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

In order to find convenient crystals as model compounds for investigation of the electronic structure of Fe^II complexes, the title compound was prepared. The unit cell contains two Fe^II cations situated on centres of inversion, four Na⁺ cations, four SO₄^2- anions and eight water molecules. The structure contains a three-dimensional network of O—H···O hydrogen bonds.

In the title compound (Fig. 1), the Fe1—O8 [2.115 (1) Å] and Fe1—O9 [2.170 (1) Å] bond lengths are in reasonable agreement with a similar compounds in the Cambridge Structural Database (CSD; Version 5.27, 2006 release). For example, in ethylenediammonium tetra-aqua-bis(sulfato-O)-iron(II) (Held, 2003; CSD refcode WABHIR), the Fe—O(water) distances are 2.111 and 2.143 Å, respectively. The Fe1—O2 distance to the sulfate anion [2.095 (1) Å] compares to 2.126 Å in WABHIR. In the crystal structure of pentaaqua-(3-(diphenylphosphino)phenylsulfonato)-iron(II) (diphenyl(3-sulfonatophenyl)phosphine) (Barton et al., 2002; CSD refcode XOHHOR), there are two symmetrically independent units with corresponding distances for Fe—O(water) in the range 2.085 to 2.125 Å and for Fe—O of the sulfonato anion between 2.10 and 2.126 Å.

Related literature

For related structures, see: Held (2003); Barton et al. (2002).

S2. Experimental

A solution of 1.0 mmol of Fe(SO₄)₂ in 2 ml water with one drop of diluted H₂SO₄(aq) and a piece of Fe metal was mixed with a solution of 2.0 mmol NaNO₂NCN in 10 ml water and a solution of 2.0 mmol of imidazole in 10 ml me thanol. From this system, pale yellow crystals were isolated after a few days standing.

S3. Refinement

H atoms were located in difference Fourier maps and refined freely with isotropic displacement parameters.

Computing details

Data collection: CrysAlis CCD (Oxford Diffraction, 2007); cell refinement: CrysAlis RED (Oxford Diffraction, 2007); data reduction: CrysAlis RED (Oxford Diffraction, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 1998); software used to prepare material for publication: enCIFer (Allen et al., 2004).

Figures

	Fig. 1. The asymmetric unit of the title compound with displacement ellipsoids shown at the 30% probability level for non-H atoms.
	Fig. 2. Packing diagram viewed along the a axis. Hydrogen-bond interactions are indicated by dashed lines.

Disodium tetraaquabis(sulfonato)iron(II)

Crystal data

[FeNa2(SO4)2(H2O)4]	F(000) = 368
Mr = 366.01	Dx = 2.416 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 17533 reflections
a = 5.551 (1) Å	θ = 3.0–31.4°
b = 8.252 (1) Å	µ = 2.06 mm^−1
c = 11.162 (1) Å	T = 301 K
β = 100.20 (1)°	Block, pale yellow
V = 503.1 (1) Å^3	0.55 × 0.44 × 0.17 mm
Z = 2

Data collection

Oxford Diffraction Gemini R CCD diffractometer	1343 independent reflections
Radiation source: fine-focus sealed tube	1288 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.022
ω and ϕ scans	θmax = 29.5°, θmin = 6.6°
Absorption correction: analytical [CrysAlis RED (Oxford Diffraction, 2007), based on Clark & Reid (1995)]	h = −7→7
Tmin = 0.398, Tmax = 0.720	k = −11→11
19525 measured reflections	l = −15→15

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)] = 0.018	All H-atom parameters refined
wR(F^2) = 0.047	w = 1/[σ^2(Fo^2) + (0.0245P)^2 + 0.3061P] where P = (Fo^2 + 2Fc^2)/3
S = 1.08	(Δ/σ)max = 0.001
1343 reflections	Δρmax = 0.31 e Å^−3
96 parameters	Δρmin = −0.40 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.062 (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
O2	0.81620 (17)	0.63212 (12)	0.56957 (10)	0.0228 (2)
O4	0.70650 (19)	0.91424 (13)	0.57758 (9)	0.0234 (2)
O5	1.12799 (17)	0.82849 (12)	0.63063 (10)	0.0234 (2)
O6	0.84525 (19)	0.76778 (12)	0.76330 (9)	0.0224 (2)
O8	0.37101 (18)	0.53699 (14)	0.66515 (9)	0.01827 (19)
H8A	0.294 (4)	0.617 (3)	0.660 (2)	0.039 (6)*
H8B	0.290 (4)	0.472 (3)	0.679 (2)	0.031 (6)*
O9	0.31917 (19)	0.71528 (13)	0.41612 (10)	0.0201 (2)
H9A	0.211 (5)	0.707 (3)	0.368 (2)	0.039 (6)*
H9B	0.272 (5)	0.771 (3)	0.453 (2)	0.040 (7)*
S3	0.86989 (5)	0.78740 (3)	0.63455 (3)	0.01276 (9)
Na7	0.62761 (10)	0.56900 (7)	0.86236 (5)	0.02189 (13)
Fe1	0.5000	0.5000	0.5000	0.01297 (9)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O2	0.0175 (4)	0.0203 (5)	0.0302 (5)	−0.0039 (3)	0.0031 (4)	−0.0113 (4)
O4	0.0263 (5)	0.0248 (5)	0.0183 (4)	0.0113 (4)	0.0017 (4)	0.0034 (4)
O5	0.0148 (4)	0.0218 (5)	0.0342 (5)	−0.0049 (4)	0.0058 (4)	−0.0040 (4)
O6	0.0292 (5)	0.0243 (5)	0.0142 (4)	0.0024 (4)	0.0054 (4)	0.0024 (4)
O8	0.0190 (4)	0.0188 (5)	0.0182 (4)	0.0011 (4)	0.0068 (3)	0.0005 (4)
O9	0.0203 (5)	0.0178 (5)	0.0198 (5)	0.0025 (4)	−0.0030 (4)	−0.0015 (4)
S3	0.01181 (14)	0.01334 (15)	0.01272 (15)	0.00036 (9)	0.00107 (10)	−0.00092 (10)
Na7	0.0242 (3)	0.0222 (3)	0.0185 (3)	−0.0010 (2)	0.0018 (2)	0.0011 (2)
Fe1	0.01386 (13)	0.01298 (13)	0.01206 (13)	−0.00055 (8)	0.00225 (8)	−0.00057 (8)

Geometric parameters (Å, º)

O2—S3	1.4765 (10)	O9—Na7^i	2.6122 (12)
O2—Fe1	2.0951 (9)	O9—H9A	0.74 (3)
O4—S3	1.4553 (10)	O9—H9B	0.70 (3)
O4—Na7^i	2.3683 (11)	S3—Na7^i	3.3160 (6)
O4—Na7^ii	2.4413 (11)	Na7—O4^iv	2.3684 (11)
O5—S3	1.4805 (9)	Na7—O5^v	2.3974 (11)
O5—Na7^iii	2.3975 (11)	Na7—O4^vi	2.4413 (11)
O6—S3	1.4764 (10)	Na7—O9^iv	2.6123 (12)
O6—Na7	2.4178 (11)	Na7—S3^iv	3.3160 (6)
O8—Fe1	2.1146 (9)	Na7—Na7^vii	3.7798 (11)
O8—Na7	2.4153 (11)	Na7—H8B	2.64 (2)
O8—H8A	0.78 (3)	Fe1—O2^viii	2.0951 (9)
O8—H8B	0.73 (3)	Fe1—O8^viii	2.1146 (9)
O9—Fe1	2.1695 (10)	Fe1—O9^viii	2.1695 (10)
S3—O2—Fe1	135.77 (6)	O8—Na7—O9^iv	88.81 (4)
S3—O4—Na7^i	118.30 (6)	O6—Na7—O9^iv	92.51 (4)
S3—O4—Na7^ii	134.52 (6)	O4^vi—Na7—O9^iv	74.50 (4)
Na7^i—O4—Na7^ii	103.59 (4)	O4^iv—Na7—S3^iv	22.73 (2)
S3—O5—Na7^iii	137.19 (6)	O5^v—Na7—S3^iv	97.50 (3)
S3—O6—Na7	131.26 (6)	O8—Na7—S3^iv	162.20 (3)
Fe1—O8—Na7	125.04 (5)	O6—Na7—S3^iv	91.27 (3)
Fe1—O8—H8A	108.5 (17)	O4^vi—Na7—S3^iv	98.04 (3)
Na7—O8—H8A	102.0 (17)	O9^iv—Na7—S3^iv	73.86 (3)
Fe1—O8—H8B	113.3 (17)	O4^iv—Na7—Na7^vii	38.89 (3)
Na7—O8—H8B	99.8 (17)	O5^v—Na7—Na7^vii	90.89 (3)
H8A—O8—H8B	106 (2)	O8—Na7—Na7^vii	117.55 (3)
Fe1—O9—Na7^i	112.65 (4)	O6—Na7—Na7^vii	149.97 (4)
Fe1—O9—H9A	120.0 (19)	O4^vi—Na7—Na7^vii	37.52 (2)
Na7^i—O9—H9A	111.8 (19)	O9^iv—Na7—Na7^vii	70.32 (3)
Fe1—O9—H9B	118 (2)	S3^iv—Na7—Na7^vii	60.819 (15)
Na7^i—O9—H9B	91 (2)	O4^iv—Na7—H8B	141.4 (5)
H9A—O9—H9B	99 (3)	O5^v—Na7—H8B	95.4 (5)
O4—S3—O6	110.26 (6)	O8—Na7—H8B	15.9 (5)
O4—S3—O2	110.70 (6)	O6—Na7—H8B	101.2 (5)
O6—S3—O2	109.73 (6)	O4^vi—Na7—H8B	65.5 (5)
O4—S3—O5	110.72 (6)	O9^iv—Na7—H8B	88.8 (5)
O6—S3—O5	108.11 (6)	S3^iv—Na7—H8B	159.2 (5)
O2—S3—O5	107.24 (6)	Na7^vii—Na7—H8B	102.8 (5)
O6—S3—Na7^i	146.99 (4)	O2^viii—Fe1—O2	180.0
O2—S3—Na7^i	81.15 (5)	O2^viii—Fe1—O8	90.43 (4)
O5—S3—Na7^i	97.39 (5)	O2—Fe1—O8	89.57 (4)
O4^iv—Na7—O5^v	90.76 (4)	O2^viii—Fe1—O8^viii	89.57 (4)
O4^iv—Na7—O8	154.70 (4)	O2—Fe1—O8^viii	90.43 (4)
O5^v—Na7—O8	100.26 (4)	O8—Fe1—O8^viii	180.0
O4^iv—Na7—O6	114.00 (4)	O2^viii—Fe1—O9^viii	91.55 (4)
O5^v—Na7—O6	104.53 (4)	O2—Fe1—O9^viii	88.45 (4)
O8—Na7—O6	85.36 (4)	O8—Fe1—O9^viii	86.80 (4)
O4^iv—Na7—O4^vi	76.41 (4)	O8^viii—Fe1—O9^viii	93.20 (4)
O5^v—Na7—O4^vi	90.63 (4)	O2^viii—Fe1—O9	88.45 (4)
O8—Na7—O4^vi	80.73 (4)	O2—Fe1—O9	91.55 (4)
O6—Na7—O4^vi	161.06 (4)	O8—Fe1—O9	93.20 (4)
O4^iv—Na7—O9^iv	74.82 (4)	O8^viii—Fe1—O9	86.80 (4)
O5^v—Na7—O9^iv	161.21 (4)	O9^viii—Fe1—O9	179.999 (1)
Na7^i—O4—S3—O6	−164.83 (6)	Fe1—O8—Na7—O9^iv	142.28 (6)
Na7^ii—O4—S3—O6	−10.15 (11)	Fe1—O8—Na7—S3^iv	129.32 (9)
Na7^i—O4—S3—O2	−43.22 (8)	Fe1—O8—Na7—Na7^vii	−150.72 (5)
Na7^ii—O4—S3—O2	111.45 (9)	S3—O6—Na7—O4^iv	172.17 (7)
Na7^i—O4—S3—O5	75.58 (8)	S3—O6—Na7—O5^v	74.68 (8)
Na7^ii—O4—S3—O5	−129.75 (9)	S3—O6—Na7—O8	−24.74 (8)
Na7^ii—O4—S3—Na7^i	154.67 (13)	S3—O6—Na7—O4^vi	−67.51 (16)
Na7—O6—S3—O4	101.13 (8)	S3—O6—Na7—O9^iv	−113.34 (8)
Na7—O6—S3—O2	−21.05 (9)	S3—O6—Na7—S3^iv	172.76 (7)
Na7—O6—S3—O5	−137.70 (7)	S3—O6—Na7—Na7^vii	−166.63 (6)
Na7—O6—S3—Na7^i	83.55 (10)	S3—O2—Fe1—O8	−46.73 (10)
Fe1—O2—S3—O4	−45.49 (11)	S3—O2—Fe1—O8^viii	133.27 (10)
Fe1—O2—S3—O6	76.42 (10)	S3—O2—Fe1—O9^viii	−133.54 (10)
Fe1—O2—S3—O5	−166.38 (9)	S3—O2—Fe1—O9	46.46 (10)
Fe1—O2—S3—Na7^i	−71.33 (9)	Na7—O8—Fe1—O2^viii	150.22 (6)
Na7^iii—O5—S3—O4	32.62 (11)	Na7—O8—Fe1—O2	−29.78 (6)
Na7^iii—O5—S3—O6	−88.26 (10)	Na7—O8—Fe1—O9^viii	58.69 (6)
Na7^iii—O5—S3—O2	153.49 (9)	Na7—O8—Fe1—O9	−121.31 (6)
Na7^iii—O5—S3—Na7^i	70.50 (9)	Na7^i—O9—Fe1—O2^viii	−152.73 (5)
Fe1—O8—Na7—O4^iv	−168.78 (8)	Na7^i—O9—Fe1—O2	27.27 (5)
Fe1—O8—Na7—O5^v	−54.28 (7)	Na7^i—O9—Fe1—O8	116.93 (5)
Fe1—O8—Na7—O6	49.67 (6)	Na7^i—O9—Fe1—O8^viii	−63.07 (5)
Fe1—O8—Na7—O4^vi	−143.24 (7)

Symmetry codes: (i) x, −y+3/2, z−1/2; (ii) −x+1, y+1/2, −z+3/2; (iii) −x+2, y+1/2, −z+3/2; (iv) x, −y+3/2, z+1/2; (v) −x+2, y−1/2, −z+3/2; (vi) −x+1, y−1/2, −z+3/2; (vii) −x+1, −y+1, −z+2; (viii) −x+1, −y+1, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O8—H8A···O5^ix	0.78 (3)	1.97 (3)	2.7513 (15)	172 (2)
O8—H8B···O6^vi	0.73 (3)	2.00 (3)	2.7116 (15)	165 (2)
O9—H9A···O6^x	0.74 (3)	2.16 (3)	2.8741 (14)	162 (2)
O9—H9B···O5^ix	0.70 (3)	2.32 (3)	2.9379 (15)	150 (3)

Symmetry codes: (vi) −x+1, y−1/2, −z+3/2; (ix) x−1, y, z; (x) x−1, −y+3/2, z−1/2.