Magnesium dichloride decahydrate (MgCl
2·10H
2O) and its deuterated counterpart (MgCl
2·10D
2O) are identified for the first time by
in-situ powder synchrotron X-ray and spallation neutron diffraction. These substances are crystallized from a previously unidentified nanocrystalline compound, which originates from an amorphous state at low temperature. A combination of a recently developed autoindexing procedure and the charge-flipping method reveals that the crystal structure of MgCl
2·10H
2O consists of an ABCABC
sequence of Mg(H
2O)
6 octahedra. The Cl
− anions and remaining water molecules unconnected to the Mg
2+ cations bind the octahedra, similar to other water-rich magnesium dichloride hydrates. The D positions in MgCl
2·10D
2O, determined by the difference Fourier methods using the neutron powder diffraction patterns at 2.5 GPa, show the features such as bifurcated hydrogen bonds and tetrahedrally coordinated O atoms, which were not found in other forms of magnesium chloride hydrates.
Supporting information
Crystal data, data collection and structure refinement details are summarized
in Table 1.
S2. Results and discussion
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(11615_phase_1) Deuterium oxide
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Crystal data top
D2.00O | Z = 2 |
Mr = 20.03 | Dx = 1.773 Mg m−3 |
Cubic, Pn3m | ? radiation |
a = 3.347183 (18) Å | T = 298 K |
V = 37.50 (1) Å3 | irregular, ? × ? × ? mm |
Data collection top
PLANET (BL11), Materials and Life Science Experimental Facility, J-PARC
Tokai, Ibaraki, Japan diffractometer | Data collection mode: transmission |
Radiation source: neutron | Scan method: time of flight |
Specimen mounting: Pressure-tempearture variable system ('the MITO system') | 2θfixed = 90.00 |
Refinement top
Least-squares matrix: full | 3715 data points |
Rp = 0.025 | Profile function: TOF Profile function number-3 with 21 terms
Profile coefficients for exponential pseudovoigt
convolution Von Dreele, 1990 (unpublished)
#1 (alp ) = 0.0000 #2 (bet-0) = 0.000000 #3 (bet-1) = 0.000000
#4 (sig-0) = 12.6 #5 (sig-1) = 496.8 #6 (sig-2) = 2.2
#7 (gam-0) = 0.00 #8 (gam-1) = 6.72 #9 (gam-2) = 2.90
#10(gsf ) = 0.00 #11(g1ec ) = 0.00 #12(g2ec ) = 0.00
#13(rstr ) = 0.000 #14(rsta ) = 0.000 #15(rsca ) = 0.000
#16(L11) = 0.000 #17(L22) = 0.000 #18(L33) = 0.000
#19(L12) = 0.000 #20(L13) = 0.000 #21(L23) = 0.000
Peak tails are ignored where the intensity is below 0.0010 times the peak
Aniso. broadening axis 0.0 0.0 1.0, TOF Profile function number-3 with 21 terms
Profile coefficients for exponential pseudovoigt
convolution Von Dreele, 1990 (unpublished)
#1 (alp ) = 0.0000 #2 (bet-0) = 0.000000 #3 (bet-1) = 0.000000
#4 (sig-0) = 12.6 #5 (sig-1) = 547.3 #6 (sig-2) = 2.2
#7 (gam-0) = 0.00 #8 (gam-1) = 0.00 #9 (gam-2) = 5.69
#10(gsf ) = 0.00 #11(g1ec ) = 0.00 #12(g2ec ) = 0.00
#13(rstr ) = 0.000 #14(rsta ) = 0.000 #15(rsca ) = 0.000
#16(L11) = 0.000 #17(L22) = 0.000 #18(L33) = 0.000
#19(L12) = 0.000 #20(L13) = 0.000 #21(L23) = 0.000
Peak tails are ignored where the intensity is below 0.0010 times the peak
Aniso. broadening axis 0.0 0.0 1.0 |
Rwp = 0.028 | 47 parameters |
Rexp = 0.014 | 0 restraints |
R(F2) = 0.20166 | (Δ/σ)max = 0.05 |
χ2 = 3.842 | Background function: GSAS Background function number 1 with 18 terms.
Shifted Chebyshev function of 1st kind
1: 0.127013 2: -2.953800E-02 3: -5.451210E-03 4: -4.201140E-03
5: -1.768310E-03 6: 4.145860E-03 7: -5.281160E-03 8: 3.322800E-03
9: -1.798060E-0310: -8.129380E-0411: 2.257130E-0312: -1.843770E-03
13: 1.555140E-0314: -4.858040E-0415: 1.835960E-0316: -4.809670E-04
17: -4.887130E-0418: 1.330830E-03 |
Crystal data top
D2.00O | Z = 2 |
Mr = 20.03 | ? radiation |
Cubic, Pn3m | T = 298 K |
a = 3.347183 (18) Å | irregular, ? × ? × ? mm |
V = 37.50 (1) Å3 | |
Data collection top
PLANET (BL11), Materials and Life Science Experimental Facility, J-PARC
Tokai, Ibaraki, Japan diffractometer | Scan method: time of flight |
Specimen mounting: Pressure-tempearture variable system ('the MITO system') | 2θfixed = 90.00 |
Data collection mode: transmission | |
Refinement top
Rp = 0.025 | χ2 = 3.842 |
Rwp = 0.028 | 3715 data points |
Rexp = 0.014 | 47 parameters |
R(F2) = 0.20166 | 0 restraints |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | Occ. (<1) |
D1 | 0.4254 (7) | 0.4254 (7) | 0.3768 (13) | 0.0182 (4)* | 0.1667 |
O1 | 0.25 | 0.25 | 0.25 | 0.01592 (18)* | |
Geometric parameters (Å, º) top
Mg1—O1 | 2.098 (10) | O2—D4 | 0.927 (8) |
Mg1—O1i | 2.098 (10) | O3—D1 | 1.759 (9) |
Mg1—O2 | 2.081 (7) | O3—D1vii | 1.759 (9) |
Mg1—O2i | 2.081 (7) | O3—D3 | 0.977 (7) |
Mg1—O2ii | 2.081 (7) | O3—D3vii | 0.977 (7) |
Mg1—O2iii | 2.081 (7) | O4—D2viii | 1.840 (9) |
Mg1—D1 | 2.742 (7) | O4—D2ix | 1.840 (9) |
Mg1—D1i | 2.742 (7) | O4—D5 | 0.877 (12) |
Mg1—D1ii | 2.742 (7) | O4—D6 | 0.971 (11) |
Mg1—D1iii | 2.742 (7) | D1—Mg1 | 2.742 (7) |
Mg1—D2 | 2.628 (6) | D1—O1 | 1.010 (8) |
Mg1—D2i | 2.628 (6) | D1—O3 | 1.759 (9) |
Mg1—D2ii | 2.628 (6) | D1—D1iii | 1.631 (13) |
Mg1—D2iii | 2.628 (6) | D2—Mg1 | 2.628 (6) |
Mg1—D4 | 2.671 (7) | D2—O2 | 0.952 (7) |
Mg1—D4i | 2.671 (7) | D2—O4x | 1.840 (9) |
Mg1—D4ii | 2.671 (7) | D2—D4 | 1.479 (9) |
Mg1—D4iii | 2.671 (7) | D3—Cl1xi | 2.038 (7) |
Cl1—D3iv | 2.038 (7) | D3—O3 | 0.977 (7) |
Cl1—D3v | 2.038 (7) | D3—D3vii | 1.656 (11) |
Cl1—D4 | 2.619 (10) | D4—Mg1 | 2.671 (7) |
Cl1—D4iii | 2.619 (10) | D4—Cl1 | 2.619 (10) |
Cl1—D4iv | 2.460 (9) | D4—Cl1xi | 2.460 (9) |
Cl1—D4v | 2.460 (9) | D4—O2 | 0.927 (8) |
Cl1—D5vi | 2.286 (11) | D4—D2 | 1.479 (9) |
O1—Mg1 | 2.098 (10) | D5—Cl1vi | 2.286 (11) |
O1—D1 | 1.010 (8) | D5—O4 | 0.877 (12) |
O1—D1iii | 1.010 (8) | D5—D6 | 1.555 (10) |
O2—Mg1 | 2.081 (7) | D6—O4 | 0.971 (11) |
O2—D2 | 0.952 (7) | D6—D5 | 1.555 (10) |
| | | |
O1—Mg1—O1i | 180.0 | D3iv—Cl1—D3v | 79.4 (3) |
O1—Mg1—O2 | 94.4 (3) | Mg1—O1—D1 | 119.6 (7) |
O1—Mg1—O2i | 85.6 (3) | Mg1—O1—D1iii | 119.6 (7) |
O1—Mg1—O2ii | 85.6 (3) | D1—O1—D1iii | 107.8 (14) |
O1—Mg1—O2iii | 94.4 (3) | Mg1—O2—D2 | 114.9 (7) |
O1i—Mg1—O2 | 85.6 (3) | Mg1—O2—D4 | 120.3 (8) |
O1i—Mg1—O2i | 94.4 (3) | D2—O2—D4 | 103.8 (10) |
O1i—Mg1—O2ii | 94.4 (3) | D3—O3—D3vii | 115.9 (13) |
O1i—Mg1—O2iii | 85.6 (3) | D5—O4—D6 | 114.5 (15) |
O2—Mg1—O2i | 92.1 (4) | O2—D2—D4 | 37.5 (6) |
O2—Mg1—O2ii | 180.0 | Cl1xi—D3—O3 | 170.1 (7) |
O2—Mg1—O2iii | 87.9 (4) | O2—D4—D2 | 38.7 (5) |
O2i—Mg1—O2ii | 87.9 (4) | O4—D5—D6 | 34.6 (9) |
O2i—Mg1—O2iii | 180.0 | O4—D6—D5 | 30.9 (8) |
O2ii—Mg1—O2iii | 92.1 (4) | | |
Symmetry codes: (i) z, x, y; (ii) y, z, x; (iii) x+1/2, y+1/2, −z; (iv) y+1/2, −z−1, x+3/2; (v) −z+1/2, x, −y+3/2; (vi) z+1, x, y+1; (vii) z, x, y+1; (viii) y+1/2, −z−1, x+1/2; (ix) −z+1/2, x, −y+1/2; (x) y+1/2, −z, x+1/2; (xi) y+1/2, −z, x+3/2. |
(11615_phase_2) Magnesium chloride decadeuterate
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Crystal data top
Cl2D20MgO10 | V = 534.1 (5) Å3 |
Mr = 295.48 | Z = 2 |
Monoclinic, C2/m | Dx = 1.837 Mg m−3 |
a = 10.3368 (2) Å | ? radiation |
b = 7.4681 (3) Å | T = 298 K |
c = 7.7232 (3) Å | irregular, ? × ? × ? mm |
β = 116.3813 (17)° | |
Data collection top
PLANET (BL11), Materials and Life Science Experimental Facility, J-PARC
Tokai, Ibaraki, Japan diffractometer | Data collection mode: transmission |
Radiation source: neutron | Scan method: time of flight |
Specimen mounting: Pressure-tempearture variable system ('the MITO system') | 2θfixed = 90.00 |
Refinement top
Least-squares matrix: full | 3715 data points |
Rp = 0.025 | Profile function: TOF Profile function number-3 with 21 terms
Profile coefficients for exponential pseudovoigt
convolution Von Dreele, 1990 (unpublished)
#1 (alp ) = 0.0000 #2 (bet-0) = 0.000000 #3 (bet-1) = 0.000000
#4 (sig-0) = 12.6 #5 (sig-1) = 496.8 #6 (sig-2) = 2.2
#7 (gam-0) = 0.00 #8 (gam-1) = 6.72 #9 (gam-2) = 2.90
#10(gsf ) = 0.00 #11(g1ec ) = 0.00 #12(g2ec ) = 0.00
#13(rstr ) = 0.000 #14(rsta ) = 0.000 #15(rsca ) = 0.000
#16(L11) = 0.000 #17(L22) = 0.000 #18(L33) = 0.000
#19(L12) = 0.000 #20(L13) = 0.000 #21(L23) = 0.000
Peak tails are ignored where the intensity is below 0.0010 times the peak
Aniso. broadening axis 0.0 0.0 1.0, TOF Profile function number-3 with 21 terms
Profile coefficients for exponential pseudovoigt
convolution Von Dreele, 1990 (unpublished)
#1 (alp ) = 0.0000 #2 (bet-0) = 0.000000 #3 (bet-1) = 0.000000
#4 (sig-0) = 12.6 #5 (sig-1) = 547.3 #6 (sig-2) = 2.2
#7 (gam-0) = 0.00 #8 (gam-1) = 0.00 #9 (gam-2) = 5.69
#10(gsf ) = 0.00 #11(g1ec ) = 0.00 #12(g2ec ) = 0.00
#13(rstr ) = 0.000 #14(rsta ) = 0.000 #15(rsca ) = 0.000
#16(L11) = 0.000 #17(L22) = 0.000 #18(L33) = 0.000
#19(L12) = 0.000 #20(L13) = 0.000 #21(L23) = 0.000
Peak tails are ignored where the intensity is below 0.0010 times the peak
Aniso. broadening axis 0.0 0.0 1.0 |
Rwp = 0.028 | 47 parameters |
Rexp = 0.014 | 0 restraints |
R(F2) = 0.20166 | (Δ/σ)max = 0.05 |
χ2 = 3.842 | Background function: GSAS Background function number 1 with 18 terms.
Shifted Chebyshev function of 1st kind
1: 0.127013 2: -2.953800E-02 3: -5.451210E-03 4: -4.201140E-03
5: -1.768310E-03 6: 4.145860E-03 7: -5.281160E-03 8: 3.322800E-03
9: -1.798060E-0310: -8.129380E-0411: 2.257130E-0312: -1.843770E-03
13: 1.555140E-0314: -4.858040E-0415: 1.835960E-0316: -4.809670E-04
17: -4.887130E-0418: 1.330830E-03 |
Crystal data top
Cl2D20MgO10 | β = 116.3813 (17)° |
Mr = 295.48 | V = 534.1 (5) Å3 |
Monoclinic, C2/m | Z = 2 |
a = 10.3368 (2) Å | ? radiation |
b = 7.4681 (3) Å | T = 298 K |
c = 7.7232 (3) Å | irregular, ? × ? × ? mm |
Data collection top
PLANET (BL11), Materials and Life Science Experimental Facility, J-PARC
Tokai, Ibaraki, Japan diffractometer | Scan method: time of flight |
Specimen mounting: Pressure-tempearture variable system ('the MITO system') | 2θfixed = 90.00 |
Data collection mode: transmission | |
Refinement top
Rp = 0.025 | χ2 = 3.842 |
Rwp = 0.028 | 3715 data points |
Rexp = 0.014 | 47 parameters |
R(F2) = 0.20166 | 0 restraints |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
Mg1 | 0.0 | 0.0 | 0.0 | 0.005 (3)* | |
Cl1 | 0.2873 (6) | 0.0 | 0.5491 (10) | 0.029 (2)* | |
O1 | −0.0686 (10) | 0.0 | 0.2181 (16) | 0.022 (3)* | |
O2 | 0.1584 (8) | 0.1934 (10) | 0.1331 (12) | 0.022 (2)* | |
O3 | 0.0 | 0.2562 (15) | 0.5 | 0.031 (3)* | |
O4 | 0.4028 (14) | 0.0 | 0.0953 (15) | 0.035 (3)* | |
D1 | −0.0517 (8) | 0.1092 (9) | 0.3024 (8) | 0.0340 (8)* | |
D2 | 0.1412 (7) | 0.3047 (9) | 0.0662 (9) | 0.0340 (8)* | |
D3 | 0.0779 (6) | 0.3256 (8) | 0.4936 (9) | 0.0340 (8)* | |
D4 | 0.1849 (6) | 0.2264 (10) | 0.2601 (11) | 0.0340 (8)* | |
D5 | 0.4861 (9) | 0.0 | 0.1988 (14) | 0.0340 (8)* | |
D6 | 0.3192 (9) | 0.0 | 0.1215 (13) | 0.0340 (8)* | |
Geometric parameters (Å, º) top
Mg1—O1 | 2.098 (10) | O2—D4 | 0.927 (8) |
Mg1—O1i | 2.098 (10) | O3—D1 | 1.759 (9) |
Mg1—O2 | 2.081 (7) | O3—D1vii | 1.759 (9) |
Mg1—O2i | 2.081 (7) | O3—D3 | 0.977 (7) |
Mg1—O2ii | 2.081 (7) | O3—D3vii | 0.977 (7) |
Mg1—O2iii | 2.081 (7) | O4—D2viii | 1.840 (9) |
Mg1—D1 | 2.742 (7) | O4—D2ix | 1.840 (9) |
Mg1—D1i | 2.742 (7) | O4—D5 | 0.877 (12) |
Mg1—D1ii | 2.742 (7) | O4—D6 | 0.971 (11) |
Mg1—D1iii | 2.742 (7) | D1—Mg1 | 2.742 (7) |
Mg1—D2 | 2.628 (6) | D1—O1 | 1.010 (8) |
Mg1—D2i | 2.628 (6) | D1—O3 | 1.759 (9) |
Mg1—D2ii | 2.628 (6) | D1—D1iii | 1.631 (13) |
Mg1—D2iii | 2.628 (6) | D2—Mg1 | 2.628 (6) |
Mg1—D4 | 2.671 (7) | D2—O2 | 0.952 (7) |
Mg1—D4i | 2.671 (7) | D2—O4x | 1.840 (9) |
Mg1—D4ii | 2.671 (7) | D2—D4 | 1.479 (9) |
Mg1—D4iii | 2.671 (7) | D3—Cl1xi | 2.038 (7) |
Cl1—D3iv | 2.038 (7) | D3—O3 | 0.977 (7) |
Cl1—D3v | 2.038 (7) | D3—D3vii | 1.656 (11) |
Cl1—D4 | 2.619 (10) | D4—Mg1 | 2.671 (7) |
Cl1—D4iii | 2.619 (10) | D4—Cl1 | 2.619 (10) |
Cl1—D4iv | 2.460 (9) | D4—Cl1xi | 2.460 (9) |
Cl1—D4v | 2.460 (9) | D4—O2 | 0.927 (8) |
Cl1—D5vi | 2.286 (11) | D4—D2 | 1.479 (9) |
O1—Mg1 | 2.098 (10) | D5—Cl1vi | 2.286 (11) |
O1—D1 | 1.010 (8) | D5—O4 | 0.877 (12) |
O1—D1iii | 1.010 (8) | D5—D6 | 1.555 (10) |
O2—Mg1 | 2.081 (7) | D6—O4 | 0.971 (11) |
O2—D2 | 0.952 (7) | D6—D5 | 1.555 (10) |
| | | |
O1—Mg1—O1i | 180.0 | D3iv—Cl1—D3v | 79.4 (3) |
O1—Mg1—O2 | 94.4 (3) | Mg1—O1—D1 | 119.6 (7) |
O1—Mg1—O2i | 85.6 (3) | Mg1—O1—D1iii | 119.6 (7) |
O1—Mg1—O2ii | 85.6 (3) | D1—O1—D1iii | 107.8 (14) |
O1—Mg1—O2iii | 94.4 (3) | Mg1—O2—D2 | 114.9 (7) |
O1i—Mg1—O2 | 85.6 (3) | Mg1—O2—D4 | 120.3 (8) |
O1i—Mg1—O2i | 94.4 (3) | D2—O2—D4 | 103.8 (10) |
O1i—Mg1—O2ii | 94.4 (3) | D3—O3—D3vii | 115.9 (13) |
O1i—Mg1—O2iii | 85.6 (3) | D5—O4—D6 | 114.5 (15) |
O2—Mg1—O2i | 92.1 (4) | O2—D2—D4 | 37.5 (6) |
O2—Mg1—O2ii | 180.0 | Cl1xi—D3—O3 | 170.1 (7) |
O2—Mg1—O2iii | 87.9 (4) | O2—D4—D2 | 38.7 (5) |
O2i—Mg1—O2ii | 87.9 (4) | O4—D5—D6 | 34.6 (9) |
O2i—Mg1—O2iii | 180.0 | O4—D6—D5 | 30.9 (8) |
O2ii—Mg1—O2iii | 92.1 (4) | | |
Symmetry codes: (i) −x, y, −z; (ii) −x, −y, −z; (iii) x, −y, z; (iv) −x+1/2, y−1/2, −z+1; (v) −x+1/2, −y+1/2, −z+1; (vi) −x+1, y, −z+1; (vii) −x, y, −z+1; (viii) −x+1/2, y−1/2, −z; (ix) −x+1/2, −y+1/2, −z; (x) −x+1/2, y+1/2, −z; (xi) −x+1/2, y+1/2, −z+1. |
Experimental details
| (11615_phase_1) | (11615_phase_2) |
Crystal data |
Chemical formula | D2.00O | Cl2D20MgO10 |
Mr | 20.03 | 295.48 |
Crystal system, space group | Cubic, Pn3m | Monoclinic, C2/m |
Temperature (K) | 298 | 298 |
a, b, c (Å) | 3.347183 (18), 3.347183, 3.347183 | 10.3368 (2), 7.4681 (3), 7.7232 (3) |
α, β, γ (°) | 90, 90, 90 | 90, 116.3813 (17), 90 |
V (Å3) | 37.50 (1) | 534.1 (5) |
Z | 2 | 2 |
Radiation type | ? | ? |
µ (mm−1) | ? | ? |
Specimen shape, size (mm) | Irregular, ? × ? × ? | Irregular, ? × ? × ? |
|
Data collection |
Data collection method | PLANET (BL11), Materials and Life Science Experimental Facility, J-PARC
Tokai, Ibaraki, Japan | PLANET (BL11), Materials and Life Science Experimental Facility, J-PARC
Tokai, Ibaraki, Japan |
Specimen mounting | Pressure-tempearture variable system ('the MITO system') | Pressure-tempearture variable system ('the MITO system') |
Data collection mode | Transmission | Transmission |
Scan method | Time of flight | Time of flight |
Absorption correction | ? GSAS Absorption/surface roughness correction: function number 0
No correction is applied. | – |
Tmin, Tmax | 1.000, 1.000 | – |
2θ values (°) | 2θfixed = 90.00 | 2θfixed = 90.00 |
|
Refinement |
R factors and goodness of fit | Rp = 0.025, Rwp = 0.028, Rexp = 0.014, R(F2) = 0.20166, χ2 = 3.842 | Rp = 0.025, Rwp = 0.028, Rexp = 0.014, R(F2) = 0.20166, χ2 = 3.842 |
No. of data points | 3715 | 3715 |
No. of parameters | 47 | 47 |