Tetra­aqua­diglycinemagnesium(II) hexa­aqua­magnesium(II) bis­(sulfate)

In the title compound, [Mg(C₂H₅NO₂)₂(H₂O)₄][Mg(H₂O)₆](SO₄)₂, the Mg^II atoms of both dications lie on inversion centres, and each of them is in an octa­hedral coordination environment. The glycine mol­ecule exists in the zwitterionic form. The [Mg(H₂O)₆]²⁺ and [Mg(C₂H₅NO₂)₂(H₂O)₄]²⁺ dications pack as alternate layers parallel to the ab plane, with the sulfate anions lying between them. The ions are linked to form a three-dimensional network by O—H...O and N—H...O hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.066
• wR factor = 0.171
• Data-to-parameter ratio = 9.9

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT088_ALERT_3_C Poor Data / Parameter Ratio ....................       9.94
PLAT154_ALERT_1_C The su's on the Cell Angles are Equal  (x 10000)       2000 Deg.
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....       2.35
PLAT731_ALERT_1_C Bond    Calc     0.85(3), Rep   0.846(10) ......       3.00 su-Ra
              O5   -H5B     1.555   1.555
PLAT731_ALERT_1_C Bond    Calc     0.84(3), Rep   0.842(10) ......       3.00 su-Ra
              O5   -H5A     1.555   1.555
PLAT731_ALERT_1_C Bond    Calc     0.83(3), Rep   0.838(10) ......       3.00 su-Ra
              O6   -H6B     1.555   1.555
PLAT731_ALERT_1_C Bond    Calc     0.84(3), Rep   0.838(10) ......       3.00 su-Ra
              O6   -H6A     1.555   1.555
PLAT731_ALERT_1_C Bond    Calc     0.84(3), Rep   0.835(10) ......       3.00 su-Ra
              O9   -H9B     1.555   1.555
PLAT731_ALERT_1_C Bond    Calc     0.84(3), Rep   0.844(10) ......       3.00 su-Ra
              O10  -H10B    1.555   1.555
PLAT731_ALERT_1_C Bond    Calc     0.84(4), Rep   0.842(10) ......       4.00 su-Ra
              O10  -H10A    1.555   1.555
PLAT731_ALERT_1_C Bond    Calc     0.83(3), Rep   0.837(10) ......       3.00 su-Ra
              O11  -H11B    1.555   1.555
PLAT731_ALERT_1_C Bond    Calc     0.84(3), Rep   0.836(10) ......       3.00 su-Ra
              O11  -H11A    1.555   1.555
PLAT735_ALERT_1_C D-H     Calc     0.84(3), Rep   0.840(10) ......       3.00 su-Ra
              O5   -H5A     1.555   1.555
PLAT735_ALERT_1_C D-H     Calc     0.85(3), Rep   0.850(10) ......       3.00 su-Ra
              O5   -H5B     1.555   1.555
PLAT735_ALERT_1_C D-H     Calc     0.84(3), Rep   0.840(10) ......       3.00 su-Ra
              O6   -H6A     1.555   1.555
PLAT735_ALERT_1_C D-H     Calc     0.83(3), Rep   0.840(10) ......       3.00 su-Ra
              O6   -H6B     1.555   1.555
PLAT735_ALERT_1_C D-H     Calc     0.84(3), Rep   0.840(10) ......       3.00 su-Ra
              O9   -H9B     1.555   1.555
PLAT735_ALERT_1_C D-H     Calc     0.84(4), Rep   0.840(10) ......       4.00 su-Ra
              O10  -H10A    1.555   1.555
PLAT735_ALERT_1_C D-H     Calc     0.84(3), Rep   0.840(10) ......       3.00 su-Ra
              O10  -H10B    1.555   1.555
PLAT735_ALERT_1_C D-H     Calc     0.84(3), Rep   0.840(10) ......       3.00 su-Ra
              O11  -H11A    1.555   1.555
PLAT735_ALERT_1_C D-H     Calc     0.83(3), Rep   0.840(10) ......       3.00 su-Ra
              O11  -H11B    1.555   1.555

Alert level G
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature .        293 K
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......         18

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

  22 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
   2 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

The glycine molecule is found to form many compounds with metal sulfates, metal halogenides and acids. There are many examples in the literature on glycine metallic sulfates (Peterková et al., 1991; Fleck & Bohatý, 2005). We report here the crystal structure of the title magnesium sulfate complex, with glycine.

The asymmetric unit of the title compound consists of one-half each of [Mg(H₂O)₆]²⁺ and [Mg(C₂H₅NO₂)₂(H₂O)₄]²⁺ dications, and one SO₄^2- anion (Fig. 1). The Mg^II atoms of both dications lie on inversion centres, and they are in an octahedral coordination environment. The Mg—O distances of the [Mg(H₂O)₆]²⁺ dication lie in the range 2.048 (2) Å-2.105 (2) Å (Table 1), which is in good agreement with the literature value [2.045 (4)–2.099 (4) Å; Baur, 1964]. In the [Mg(C₂H₅NO₂)₂(H₂O)₄]²⁺ dication, the Mg^II atom is coordinated by two O atoms from two glycine ligands, and four water molecules. The Mg—O distance [2.128 (2) Å] involving the glycine molecule is longer than that involving the water molecule (Table 1).

The [Mg(H₂O)₆]²⁺ and [Mg(C₂H₅NO₂)₂(H₂O)₄]²⁺ dications pack as alternate layers parallel to the ab plane, with the sulfate anions lying between them. The complex cations and sulfate anions are linked to form a three-dimensional network by O—H···O and N—H···O hydrogen bonds (Table 2).

In the crystal structure, the glycine molecule exists in the zwitterionic form, which is normal for compounds of amino acids with inorganic salts. There are also many examples in the literature of glycinum and glycinate compounds (Muller et al., 1994). The non-hydrogen atoms of the glycine molecule are coplanar, with the caboxylate C—O distances being 1.269 (4) Å [C1—O7] and 1.239 (4) Å [C1—O8].

Related literature

For related literature, see: Baur (1964); Fleck & Bohatý (2005); Muller et al. (1994); Peterková et al. (1991).

S2. Experimental

Colourless single crystals of the title compound were grown from a saturated aqueous solution. Glycine (3 g, 1.6 mol) was added to 25 ml of magnesium sulfate heptahydrate (40 g, 6.5 mol) solution at 313 K using a constant temperature water both. The solution was continuously stirred upto complete dissolution of glycine and the temperature was raised to 318 K to avoid nucleation during the filtration of the solution. This solution was subjected to solvent evaporation at room temperature and after 10 days, white tabular form of crystals were collected.

S3. Refinement

C-bound H atoms were positioned geometrically (C—H = 0.97 Å) and allowed to ride on their parent atoms, with U_iso(H) = 1.2U_eq(C). The water H atoms were located and refined with distance restraints [O—H = 0.84 (1) Å and H···H = 1.37 (2) Å]. The three N—H distances were restrained to be equal.

Computing details

Data collection: AED software/Program name? (Belletti, 2004); cell refinement: AED software/Program name? (Belletti, 2004); data reduction: AED software/Program name? (Belletti, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures

	Fig. 1. The asymmetric unit of the title compound. Displacement ellipsoids are drawn at the 50% probability level. Atoms labelled with the suffixes a and b are generated by the symmetry operations (1 - x, -y, 1 - z) and (1 - x, 1 - y, -z), respectively. Only one sulfate anion is shown.
	Fig. 2. View of the crystal structure of the title compound.

Tetraaquadiglycinemagnesium(II) hexaaquamagnesium(II) bis(sulfate)

Crystal data

[Mg(C2H5NO2)2(H2O)4][Mg(H2O)6](SO4)2	Z = 1
Mr = 571.04	F(000) = 300
Triclinic, P1	Dx = 1.775 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 5.988 (3) Å	Cell parameters from 36 reflections
b = 6.783 (2) Å	θ = 7.9–17.5°
c = 13.391 (2) Å	µ = 0.41 mm^−1
α = 85.39 (2)°	T = 293 K
β = 82.87 (2)°	Block, colourless
γ = 82.88 (2)°	0.21 × 0.19 × 0.16 mm
V = 534.4 (3) Å^3

Data collection

Siemens AED diffractometer	Rint = 0.000
Radiation source: fine-focus sealed tube	θmax = 25.5°, θmin = 1.5°
Graphite monochromator	h = −7→6
ω–2θ scans	k = −6→8
1998 measured reflections	l = −12→16
1998 independent reflections	1 standard reflections every 50 reflections
1992 reflections with I > 2σ(I)	intensity decay: none

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)] = 0.066	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.171	w = 1/[σ^2(Fo^2) + (0.1149P)^2 + 0.6843P] where P = (Fo^2 + 2Fc^2)/3
S = 1.16	(Δ/σ)max = 0.007
1998 reflections	Δρmax = 0.94 e Å^−3
201 parameters	Δρmin = −1.07 e Å^−3
18 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: 0.37 (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
S1	0.01345 (11)	0.91384 (10)	0.18807 (5)	0.0170 (3)
O1	0.1835 (4)	1.0199 (3)	0.12319 (18)	0.0300 (6)
O2	−0.0271 (4)	0.7357 (3)	0.13906 (17)	0.0279 (6)
O3	−0.2019 (4)	1.0445 (3)	0.20413 (17)	0.0282 (6)
O4	0.0986 (4)	0.8490 (4)	0.28613 (17)	0.0294 (6)
Mg1	0.5000	0.0000	0.5000	0.0184 (4)
O5	0.1910 (4)	0.1538 (4)	0.53615 (18)	0.0318 (6)
H5B	0.116 (6)	0.206 (6)	0.489 (2)	0.044 (12)*
H5A	0.101 (6)	0.150 (7)	0.5897 (17)	0.046 (13)*
O6	0.4411 (4)	0.0276 (4)	0.34899 (15)	0.0289 (6)
H6B	0.326 (4)	−0.002 (6)	0.327 (3)	0.040 (12)*
H6A	0.547 (4)	0.032 (6)	0.302 (2)	0.033 (11)*
O7	0.6414 (4)	0.2747 (3)	0.47278 (16)	0.0271 (6)
O8	0.9719 (4)	0.3338 (5)	0.3855 (2)	0.0440 (8)
N1	0.3922 (5)	0.5024 (5)	0.3456 (2)	0.0317 (7)
H2N	0.314 (7)	0.580 (6)	0.304 (3)	0.039 (11)*
H1N	0.369 (10)	0.555 (8)	0.404 (3)	0.069 (17)*
H3N	0.330 (10)	0.392 (6)	0.351 (5)	0.073 (18)*
C1	0.7621 (5)	0.3521 (5)	0.3988 (2)	0.0238 (7)
C2	0.6414 (6)	0.4810 (5)	0.3195 (2)	0.0285 (7)
H2A	0.6936	0.6117	0.3127	0.034*
H2B	0.6794	0.4221	0.2550	0.034*
Mg2	0.5000	0.5000	0.0000	0.0186 (4)
O9	0.2942 (4)	0.3973 (3)	0.12778 (17)	0.0273 (6)
H9B	0.178 (4)	0.478 (4)	0.139 (3)	0.026 (10)*
H9A	0.264 (6)	0.281 (2)	0.126 (4)	0.055 (14)*
O10	0.7834 (4)	0.3371 (4)	0.04927 (17)	0.0283 (6)
H10B	0.885 (6)	0.292 (6)	0.005 (2)	0.041 (12)*
H10A	0.777 (9)	0.249 (6)	0.097 (3)	0.067 (17)*
O11	0.5499 (4)	0.7319 (4)	0.0805 (2)	0.0351 (6)
H11B	0.462 (5)	0.835 (4)	0.092 (3)	0.040 (12)*
H11A	0.678 (4)	0.740 (6)	0.098 (4)	0.054 (14)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.0201 (5)	0.0216 (5)	0.0101 (5)	−0.0058 (3)	−0.0018 (3)	−0.0006 (3)
O1	0.0306 (13)	0.0290 (12)	0.0293 (13)	−0.0113 (10)	0.0076 (10)	0.0004 (10)
O2	0.0299 (12)	0.0317 (12)	0.0255 (12)	−0.0102 (9)	−0.0044 (9)	−0.0095 (9)
O3	0.0299 (13)	0.0316 (12)	0.0204 (11)	0.0002 (9)	0.0013 (9)	0.0032 (9)
O4	0.0335 (13)	0.0385 (13)	0.0173 (11)	−0.0045 (10)	−0.0091 (9)	0.0022 (9)
Mg1	0.0209 (7)	0.0262 (8)	0.0090 (7)	−0.0065 (5)	−0.0031 (5)	0.0016 (5)
O5	0.0248 (12)	0.0476 (14)	0.0208 (12)	0.0000 (10)	−0.0015 (9)	0.0021 (10)
O6	0.0265 (12)	0.0520 (15)	0.0109 (10)	−0.0142 (10)	−0.0034 (9)	−0.0020 (9)
O7	0.0350 (13)	0.0319 (12)	0.0158 (11)	−0.0122 (10)	−0.0032 (9)	0.0034 (9)
O8	0.0279 (13)	0.0605 (18)	0.0419 (16)	−0.0090 (12)	−0.0067 (11)	0.0176 (13)
N1	0.0319 (16)	0.0396 (17)	0.0240 (14)	−0.0035 (13)	−0.0102 (12)	0.0045 (12)
C1	0.0296 (16)	0.0278 (15)	0.0160 (14)	−0.0101 (12)	−0.0050 (12)	0.0009 (11)
C2	0.0323 (17)	0.0359 (17)	0.0172 (15)	−0.0078 (14)	−0.0018 (12)	0.0034 (13)
Mg2	0.0230 (8)	0.0219 (7)	0.0124 (7)	−0.0054 (5)	−0.0050 (5)	−0.0015 (5)
O9	0.0310 (12)	0.0282 (12)	0.0227 (12)	−0.0086 (10)	−0.0001 (9)	0.0011 (9)
O10	0.0315 (13)	0.0344 (13)	0.0171 (11)	0.0021 (10)	−0.0032 (9)	0.0016 (9)
O11	0.0277 (13)	0.0348 (13)	0.0475 (15)	−0.0036 (10)	−0.0113 (11)	−0.0199 (12)

Geometric parameters (Å, º)

S1—O1	1.473 (2)	N1—H1N	0.87 (3)
S1—O3	1.474 (2)	N1—H3N	0.87 (3)
S1—O2	1.480 (2)	C1—C2	1.517 (4)
S1—O4	1.482 (2)	C2—H2A	0.97
Mg1—O5^i	2.031 (2)	C2—H2B	0.97
Mg1—O5	2.031 (2)	Mg2—O11^ii	2.048 (2)
Mg1—O6^i	2.085 (2)	Mg2—O11	2.048 (2)
Mg1—O6	2.085 (2)	Mg2—O10^ii	2.057 (2)
Mg1—O7	2.128 (2)	Mg2—O10	2.057 (2)
Mg1—O7^i	2.128 (2)	Mg2—O9	2.105 (2)
O5—H5B	0.846 (10)	Mg2—O9^ii	2.105 (2)
O5—H5A	0.842 (10)	O9—H9B	0.835 (10)
O6—H6B	0.838 (10)	O9—H9A	0.834 (10)
O6—H6A	0.838 (10)	O10—H10B	0.844 (10)
O7—C1	1.269 (4)	O10—H10A	0.842 (10)
O8—C1	1.239 (4)	O11—H11B	0.837 (10)
N1—C2	1.481 (5)	O11—H11A	0.836 (10)
N1—H2N	0.87 (3)
O1—S1—O3	110.14 (14)	O8—C1—O7	125.9 (3)
O1—S1—O2	109.60 (14)	O8—C1—C2	116.3 (3)
O3—S1—O2	108.77 (14)	O7—C1—C2	117.8 (3)
O1—S1—O4	109.55 (15)	N1—C2—C1	111.9 (3)
O3—S1—O4	110.07 (14)	N1—C2—H2A	109.2
O2—S1—O4	108.69 (14)	C1—C2—H2A	109.2
O5^i—Mg1—O5	180.00 (13)	N1—C2—H2B	109.2
O5^i—Mg1—O6^i	89.18 (10)	C1—C2—H2B	109.2
O5—Mg1—O6^i	90.82 (10)	H2A—C2—H2B	107.9
O5^i—Mg1—O6	90.82 (10)	O11^ii—Mg2—O11	180.00 (13)
O5—Mg1—O6	89.18 (10)	O11^ii—Mg2—O10^ii	89.87 (10)
O6^i—Mg1—O6	180.0	O11—Mg2—O10^ii	90.13 (10)
O5^i—Mg1—O7	90.78 (10)	O11^ii—Mg2—O10	90.13 (10)
O5—Mg1—O7	89.22 (10)	O11—Mg2—O10	89.87 (10)
O6^i—Mg1—O7	92.84 (9)	O10^ii—Mg2—O10	180.00 (12)
O6—Mg1—O7	87.16 (9)	O11^ii—Mg2—O9	92.24 (11)
O5^i—Mg1—O7^i	89.22 (10)	O11—Mg2—O9	87.76 (11)
O5—Mg1—O7^i	90.78 (10)	O10^ii—Mg2—O9	88.69 (10)
O6^i—Mg1—O7^i	87.16 (9)	O10—Mg2—O9	91.31 (10)
O6—Mg1—O7^i	92.84 (9)	O11^ii—Mg2—O9^ii	87.76 (11)
O7—Mg1—O7^i	180.0	O11—Mg2—O9^ii	92.24 (11)
Mg1—O5—H5B	119 (3)	O10^ii—Mg2—O9^ii	91.31 (10)
Mg1—O5—H5A	131 (3)	O10—Mg2—O9^ii	88.69 (10)
H5B—O5—H5A	108 (2)	O9—Mg2—O9^ii	180.00 (15)
Mg1—O6—H6B	125 (3)	Mg2—O9—H9B	110 (3)
Mg1—O6—H6A	122 (2)	Mg2—O9—H9A	115 (3)
H6B—O6—H6A	110 (2)	H9B—O9—H9A	112 (3)
C1—O7—Mg1	133.9 (2)	Mg2—O10—H10B	117 (3)
C2—N1—H2N	116 (3)	Mg2—O10—H10A	123 (3)
C2—N1—H1N	105 (4)	H10B—O10—H10A	106 (2)
H2N—N1—H1N	107 (5)	Mg2—O11—H11B	128 (3)
C2—N1—H3N	115 (4)	Mg2—O11—H11A	120 (3)
H2N—N1—H3N	104 (5)	H11B—O11—H11A	111 (2)
H1N—N1—H3N	109 (6)
O5^i—Mg1—O7—C1	53.2 (3)	Mg1—O7—C1—O8	−90.2 (4)
O5—Mg1—O7—C1	−126.8 (3)	Mg1—O7—C1—C2	90.6 (4)
O6^i—Mg1—O7—C1	142.4 (3)	O8—C1—C2—N1	−176.7 (3)
O6—Mg1—O7—C1	−37.6 (3)	O7—C1—C2—N1	2.6 (4)

Symmetry codes: (i) −x+1, −y, −z+1; (ii) −x+1, −y+1, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1N···O7^iii	0.87 (3)	2.08 (5)	2.939 (4)	168 (4)
N1—H2N···O4	0.87 (3)	2.12 (4)	2.877 (4)	145 (4)
N1—H3N···O6	0.87 (3)	2.48 (4)	3.195 (5)	140 (5)
N1—H3N···O8^iv	0.87 (3)	2.21 (6)	2.865 (4)	131 (4)
O5—H5A···O4^v	0.84 (1)	1.92 (3)	2.765 (4)	178 (6)
O5—H5B···O8^iv	0.85 (1)	1.83 (3)	2.673 (4)	175 (3)
O6—H6A···O3^vi	0.84 (1)	1.87 (3)	2.710 (4)	176 (3)
O6—H6B···O4^vii	0.84 (1)	1.95 (3)	2.755 (4)	163 (4)
O9—H9A···O1^vii	0.83 (1)	1.90 (2)	2.730 (3)	178 (5)
O9—H9B···O2	0.84 (1)	2.01 (3)	2.808 (3)	160 (3)
O10—H10A···O3^vi	0.84 (1)	1.92 (4)	2.755 (4)	174 (5)
O10—H10B···O2^ii	0.84 (1)	2.02 (3)	2.800 (4)	153 (3)
O11—H11A···O2^viii	0.84 (1)	1.91 (3)	2.747 (4)	175 (4)
O11—H11B···O1	0.84 (1)	1.98 (3)	2.786 (4)	162 (3)

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