The structure of [Mg(H2O)6]SO4 was redetermined at 120 K, confirming the hydrogen-bond pattern found at room temperature [Zalkin et al. (1964). Acta Cryst. 17, 235-240] but showing the librational corrections of bond lengths to be unrealistic.
Supporting information
Data collection: SMART (Bruker, 1999); cell refinement: SMART'; data reduction: SAINT (Bruker, 1999); program(s) used to solve structure: SHELXTL (Bruker, 1997); program(s) used to refine structure: SHELXTL; software used to prepare material for publication: SHELXTL.
magnesium sulfate hexahydrate
top
Crystal data top
[Mg(H2O)6]SO4 | F(000) = 960 |
Mr = 228.47 | Dx = 1.765 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
a = 9.975 (2) Å | Cell parameters from 552 reflections |
b = 7.186 (2) Å | θ = 11.9–25.7° |
c = 24.267 (6) Å | µ = 0.48 mm−1 |
β = 98.78 (1)° | T = 120 K |
V = 1719.1 (7) Å3 | Block, colourless |
Z = 8 | 0.75 × 0.40 × 0.35 mm |
Data collection top
SMART 1K CCD area-detector diffractometer | 1689 independent reflections |
Radiation source: fine-focus sealed tube | 1604 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.020 |
Detector resolution: 8 pixels mm-1 | θmax = 26.9°, θmin = 1.7° |
ω scans | h = −12→12 |
Absorption correction: multi-scan (SADABS; Sheldrick, 1998) | k = −8→8 |
Tmin = 0.679, Tmax = 0.837 | l = −29→29 |
6251 measured reflections | |
Refinement top
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.029 | Hydrogen site location: difference Fourier map |
wR(F2) = 0.078 | All H-atom parameters refined |
S = 1.19 | w = 1/[σ2(Fo2) + (0.0341P)2 + 3.381P] where P = (Fo2 + 2Fc2)/3 |
1689 reflections | (Δ/σ)max = 0.001 |
159 parameters | Δρmax = 0.33 e Å−3 |
0 restraints | Δρmin = −0.38 e Å−3 |
Special details top
Experimental. The data collection nominally covered full sphere of reciprocal space, by a
combination of 4 sets of ω scans; each set at different φ and angle and each
scan (10 sec exposure) covering 0.3° in ω. Crystal to detector distance 4.51 cm. |
Geometry. All e.s.d.'s are estimated using the full covariance matrix. |
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. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
Mg1 | 0.5000 | 0.5000 | 0.0000 | 0.0127 (2) | |
Mg2 | 1.0000 | 0.93896 (12) | 0.2500 | 0.0116 (2) | |
S | 0.86905 (4) | 0.44642 (6) | 0.12308 (2) | 0.01197 (14) | |
O1 | 0.77516 (13) | 0.59334 (18) | 0.13601 (5) | 0.0151 (3) | |
O2 | 0.98840 (14) | 0.44126 (19) | 0.16642 (6) | 0.0197 (3) | |
O3 | 0.91037 (14) | 0.48866 (19) | 0.06833 (6) | 0.0161 (3) | |
O4 | 0.79963 (13) | 0.26483 (18) | 0.11916 (6) | 0.0154 (3) | |
O5 | 0.58737 (15) | 0.7159 (2) | 0.04683 (6) | 0.0175 (3) | |
H1 | 0.643 (3) | 0.694 (4) | 0.0748 (12) | 0.028 (7)* | |
H2 | 0.549 (3) | 0.802 (4) | 0.0558 (11) | 0.024 (7)* | |
O6 | 0.53553 (16) | 0.3247 (2) | 0.06722 (7) | 0.0232 (3) | |
H3 | 0.501 (3) | 0.227 (5) | 0.0681 (12) | 0.038 (8)* | |
H4 | 0.611 (3) | 0.309 (4) | 0.0868 (11) | 0.026 (7)* | |
O7 | 0.31152 (15) | 0.5521 (2) | 0.02144 (7) | 0.0213 (3) | |
H5 | 0.302 (3) | 0.623 (4) | 0.0456 (13) | 0.030 (7)* | |
H6 | 0.243 (4) | 0.532 (5) | 0.0008 (17) | 0.055 (10)* | |
O8 | 0.88639 (14) | 1.1442 (2) | 0.28192 (6) | 0.0146 (3) | |
H7 | 0.841 (3) | 1.106 (4) | 0.3027 (11) | 0.014 (6)* | |
H8 | 0.924 (3) | 1.239 (4) | 0.2957 (12) | 0.036 (8)* | |
O9 | 0.88403 (16) | 0.7415 (2) | 0.28058 (6) | 0.0171 (3) | |
H9 | 0.914 (3) | 0.650 (5) | 0.2958 (12) | 0.034 (8)* | |
H10 | 0.810 (3) | 0.720 (4) | 0.2715 (12) | 0.031 (8)* | |
O10 | 0.85847 (15) | 0.9405 (2) | 0.17928 (6) | 0.0169 (3) | |
H11 | 0.838 (3) | 0.845 (4) | 0.1627 (12) | 0.030 (7)* | |
H12 | 0.840 (3) | 1.033 (4) | 0.1592 (11) | 0.022 (6)* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Mg1 | 0.0118 (4) | 0.0122 (4) | 0.0135 (4) | −0.0001 (3) | −0.0001 (3) | −0.0007 (3) |
Mg2 | 0.0113 (4) | 0.0115 (4) | 0.0116 (4) | 0.000 | 0.0004 (3) | 0.000 |
S | 0.0123 (2) | 0.0101 (2) | 0.0126 (2) | 0.00030 (16) | −0.00082 (17) | −0.00036 (16) |
O1 | 0.0160 (7) | 0.0134 (7) | 0.0158 (7) | 0.0027 (5) | 0.0017 (5) | −0.0007 (5) |
O2 | 0.0196 (7) | 0.0144 (7) | 0.0218 (8) | 0.0013 (5) | −0.0076 (6) | −0.0014 (6) |
O3 | 0.0175 (7) | 0.0145 (7) | 0.0169 (7) | 0.0002 (5) | 0.0045 (5) | 0.0003 (5) |
O4 | 0.0171 (7) | 0.0114 (7) | 0.0169 (7) | −0.0015 (5) | 0.0003 (5) | 0.0010 (5) |
O5 | 0.0152 (7) | 0.0162 (7) | 0.0193 (8) | 0.0029 (6) | −0.0030 (6) | −0.0046 (6) |
O6 | 0.0188 (8) | 0.0214 (8) | 0.0258 (8) | −0.0080 (6) | −0.0079 (6) | 0.0100 (6) |
O7 | 0.0143 (7) | 0.0275 (8) | 0.0213 (8) | 0.0016 (6) | 0.0005 (6) | −0.0110 (7) |
O8 | 0.0146 (7) | 0.0135 (7) | 0.0158 (7) | −0.0018 (5) | 0.0031 (6) | −0.0021 (6) |
O9 | 0.0137 (7) | 0.0158 (7) | 0.0209 (7) | −0.0011 (6) | −0.0003 (6) | 0.0054 (6) |
O10 | 0.0219 (7) | 0.0126 (7) | 0.0141 (7) | −0.0008 (6) | −0.0043 (6) | 0.0009 (6) |
Geometric parameters (Å, º) top
Mg1—O5 | 2.0385 (15) | S—O1 | 1.4764 (14) |
Mg1—O5i | 2.0385 (15) | S—O3 | 1.4814 (14) |
Mg1—O6 | 2.0485 (15) | O5—H1 | 0.82 (3) |
Mg1—O6i | 2.0485 (15) | O5—H2 | 0.78 (3) |
Mg1—O7i | 2.0601 (15) | O6—H3 | 0.78 (3) |
Mg1—O7 | 2.0601 (15) | O6—H4 | 0.83 (3) |
Mg2—O9ii | 2.0409 (16) | O7—H5 | 0.79 (3) |
Mg2—O9 | 2.0409 (16) | O7—H6 | 0.80 (4) |
Mg2—O10ii | 2.0491 (14) | O8—H7 | 0.77 (3) |
Mg2—O10 | 2.0491 (14) | O8—H8 | 0.82 (3) |
Mg2—O8 | 2.0804 (16) | O9—H9 | 0.79 (3) |
Mg2—O8ii | 2.0804 (16) | O9—H10 | 0.75 (3) |
S—O2 | 1.4638 (14) | O10—H11 | 0.80 (3) |
S—O4 | 1.4735 (14) | O10—H12 | 0.83 (3) |
| | | |
O5—Mg1—O5i | 180.00 (7) | O10ii—Mg2—O8ii | 87.89 (6) |
O5—Mg1—O6 | 90.96 (7) | O10—Mg2—O8ii | 91.67 (6) |
O5i—Mg1—O6 | 89.04 (7) | O8—Mg2—O8ii | 89.69 (9) |
O5—Mg1—O6i | 89.04 (7) | O2—S—O4 | 110.28 (8) |
O5i—Mg1—O6i | 90.96 (7) | O2—S—O1 | 109.76 (8) |
O6—Mg1—O6i | 180.00 (9) | O4—S—O1 | 109.87 (8) |
O5—Mg1—O7i | 87.13 (6) | O2—S—O3 | 110.03 (9) |
O5i—Mg1—O7i | 92.87 (6) | O4—S—O3 | 108.42 (8) |
O6—Mg1—O7i | 92.05 (7) | O1—S—O3 | 108.45 (8) |
O6i—Mg1—O7i | 87.95 (7) | Mg1—O5—H1 | 119 (2) |
O5—Mg1—O7 | 92.87 (6) | Mg1—O5—H2 | 125 (2) |
O5i—Mg1—O7 | 87.13 (6) | H1—O5—H2 | 103 (3) |
O6—Mg1—O7 | 87.95 (7) | Mg1—O6—H3 | 123 (2) |
O6i—Mg1—O7 | 92.05 (7) | Mg1—O6—H4 | 124.4 (19) |
O7i—Mg1—O7 | 180.00 (8) | H3—O6—H4 | 103 (3) |
O9ii—Mg2—O9 | 91.88 (9) | Mg1—O7—H5 | 121 (2) |
O9ii—Mg2—O10ii | 87.25 (7) | Mg1—O7—H6 | 123 (3) |
O9—Mg2—O10ii | 93.18 (7) | H5—O7—H6 | 113 (3) |
O9ii—Mg2—O10 | 93.18 (7) | Mg2—O8—H7 | 113.3 (18) |
O9—Mg2—O10 | 87.25 (7) | Mg2—O8—H8 | 120 (2) |
O10ii—Mg2—O10 | 179.38 (10) | H7—O8—H8 | 108 (3) |
O9ii—Mg2—O8 | 178.49 (7) | Mg2—O9—H9 | 124 (2) |
O9—Mg2—O8 | 89.22 (6) | Mg2—O9—H10 | 128 (2) |
O10ii—Mg2—O8 | 91.67 (6) | H9—O9—H10 | 104 (3) |
O10—Mg2—O8 | 87.89 (6) | Mg2—O10—H11 | 120 (2) |
O9ii—Mg2—O8ii | 89.22 (6) | Mg2—O10—H12 | 124.0 (18) |
O9—Mg2—O8ii | 178.49 (7) | H11—O10—H12 | 112 (3) |
Symmetry codes: (i) −x+1, −y+1, −z; (ii) −x+2, y, −z+1/2. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O5—H1···O1 | 0.82 (3) | 1.97 (3) | 2.780 (2) | 169 (3) |
O5—H2···O3iii | 0.78 (3) | 1.98 (3) | 2.741 (2) | 165 (3) |
O6—H3···O3iv | 0.78 (3) | 1.94 (4) | 2.720 (2) | 178 (3) |
O6—H4···O4 | 0.83 (3) | 1.95 (3) | 2.775 (2) | 169 (3) |
O7—H5···O4iii | 0.79 (3) | 2.06 (3) | 2.839 (2) | 168 (3) |
O7—H6···O3i | 0.80 (4) | 2.09 (4) | 2.874 (2) | 165 (4) |
O8—H7···O1v | 0.77 (3) | 2.02 (3) | 2.771 (2) | 162 (3) |
O8—H8···O2vi | 0.82 (3) | 1.86 (3) | 2.685 (2) | 174 (3) |
O9—H9···O2ii | 0.79 (3) | 1.94 (3) | 2.725 (2) | 172 (3) |
O9—H10···O8vii | 0.75 (3) | 2.24 (3) | 2.969 (2) | 162 (3) |
O10—H11···O1 | 0.80 (3) | 1.99 (3) | 2.784 (2) | 168 (3) |
O10—H12···O4viii | 0.83 (3) | 1.94 (3) | 2.765 (2) | 174 (3) |
Symmetry codes: (i) −x+1, −y+1, −z; (ii) −x+2, y, −z+1/2; (iii) x−1/2, y+1/2, z; (iv) x−1/2, y−1/2, z; (v) −x+3/2, y+1/2, −z+1/2; (vi) −x+2, y+1, −z+1/2; (vii) −x+3/2, y−1/2, −z+1/2; (viii) x, y+1, z. |