Structure refinement, microstrains and crystallite sizes of Mg-Ni-phyllosilicate nanoscroll powders

Levin, A.; Khrapova, E.; Kozlov, D.; Krasilin, A.; Gusarov, V.

doi:10.1107/S1600576722003594

Structure refinement, microstrains and crystallite sizes of Mg-Ni-phyllosilicate nanoscroll powders

A. Levin, E. Khrapova, D. Kozlov, A. Krasilin and V. Gusarov

The morphology and structure of (Ni_xMg_1−x)₃Si₂O₅(OH)₄ synthetic phyllosilicate nanoscrolls have been studied by means of electron microscopy and X-ray powder diffraction. Scrolling of phyllosilicate layers originates from size differences between octahedral and tetrahedral sheets. This strain-energy-driven process raises a number of questions, including the preferred direction of scrolling (along the a or b axis) and the presence of residual microstrain. In order to clarify these points, the structure of (Ni_xMg_1−x)₃Si₂O₅(OH)₄ phyllosilicates (x = 0, 0.33, 0.5, 0.67, 1) was first described by a monoclinic Cc (9) unit cell, whose parameters decrease with increasing Ni concentration. The Williamson–Hall plots constructed for x = 0 and 0.67 reveal the absence of microstrain, which suggests that scrolling is an effective means of stress relaxation. The sizes of the crystallites were determined by using Rietveld refinement with predefined needle-like models and fundamental parameter fitting with crystallites of arbitrary form. Both approaches show qualitative and quantitative correlation, in terms of aspect ratio, with electron microscopy data. At the same time, the phyllosilicates studied do not demonstrate one preferred direction of scrolling: instead, there might be a mixture of chirality vectors codirected with the a or b axis, with the proportion altering with Ni concentration.

Keywords: chrysotile; Rietveld refinement; nanocrystallites; transmission electron microscopy (TEM); X-ray diffraction (XRD).

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S1600576722003594/vb5023sup1.cif Contains datablocks Mg3Si2O5OH4, NiMg2Si2O5OH4, Ni1.5Mg1.5Si2O5OH4, Ni2MgSi2O5OH4, Ni3Si2O5OH4
	Rietveld powder data file (CIF format) https://doi.org/10.1107/S1600576722003594/vb5023Mg3Si2O5OH4sup2.rtv Contains datablock 00NMS
	Rietveld powder data file (CIF format) https://doi.org/10.1107/S1600576722003594/vb5023Ni1.5Mg1.5Si2O5OH4sup3.rtv Contains datablock 50NMS
	Rietveld powder data file (CIF format) https://doi.org/10.1107/S1600576722003594/vb5023Ni2MgSi2O5OH4sup4.rtv Contains datablock 67NMS
	Rietveld powder data file (CIF format) https://doi.org/10.1107/S1600576722003594/vb5023NiMg2Si2O5OH4sup5.rtv Contains datablock 33NMS
	Rietveld powder data file (CIF format) https://doi.org/10.1107/S1600576722003594/vb5023Ni3Si2O5OH4sup6.rtv Contains datablock 100NMS
	Portable Document Format (PDF) file https://doi.org/10.1107/S1600576722003594/vb5023sup7.pdf Supplementary material

CCDC references: 2163170; 2163171; 2163172; 2163173; 2163174

Computing details top

(Mg3Si2O5OH4) top

Crystal data top

Mg₆Si₄O₁₈H₈	c = 14.697 (2) Å
M_r = 554.22	β = 93.91 (2)°
Monoclinic, Cc	V = 714.06 (17) Å³
Hall symbol: C -2yc	Z = 2
a = 5.3418 (6) Å	Cu Kα radiation
b = 9.1166 (15) Å	T = 314 K

Data collection top

D2 PHASER
diffractometer

2θ_min = 5°, 2θ_max = 110°

Refinement top

R_p = 0.076

R_wp = 0.103

Special details top

Refinement. Rietveld refinement

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	B_iso*/B_eq	Occ. (<1)
Mg1	0.8922 (9)	0.2021 (6)	0.2349 (4)	0.30 (6)	1.00 (1)
Mg2	0.3738 (10)	0.3761 (7)	0.2354 (5)	0.30 (6)	1.00 (1)
Mg3	0.8859 (9)	0.5253 (8)	0.2229 (5)	0.30 (6)	1.00 (1)
Si1	0.0210 (18)	0.3649 (8)	0.0402 (4)	1.65 (7)
Si2	0.5145 (17)	0.5338 (4)	0.0391 (4)	1.65 (7)
O1	0.0691 (14)	0.1956 (10)	0.9976 (9)	1.51 (8)
O2	0.241 (2)	0.4739 (12)	0.9989 (9)	1.51 (8)
O3	0.741 (2)	0.4229 (12)	0.0034 (9)	1.51 (8)
O4	0.040 (2)	0.364 (2)	0.1564 (9)	1.51 (8)
O5	0.533 (2)	0.5380 (11)	0.1553 (9)	1.51 (8)
O6	0.738 (2)	0.3697 (15)	0.2865 (7)	1.51 (8)
O7	0.226 (3)	0.202 (2)	0.2877 (7)	1.51 (8)
O8	0.5313 (19)	0.2028 (16)	0.1831 (7)	1.51 (8)
O9	0.1978 (18)	0.5349 (18)	0.2979 (7)	1.51 (8)

(NiMg2Si2O5OH4) top

Crystal data top

Ni₂Mg₄Si₄O₁₈H₈	c = 14.7086 (11) Å
M_r = 616.99	β = 94.18 (2)°
Monoclinic, Cc	V = 714.02 (15) Å³
Hall symbol: C -2yc	Z = 2
a = 5.3444 (6) Å	Cu Kα radiation
b = 9.1074 (14) Å	T = 314 K

Data collection top

D2 PHASER
diffractometer

2θ_min = 5°, 2θ_max = 110°

Refinement top

R_p = 0.030

R_wp = 0.021

Special details top

Refinement. Rietveld refinement

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	B_iso*/B_eq	Occ. (<1)
Mg1	0.8903 (10)	0.2033 (5)	0.2341 (3)	0.10 (4)	0.79 (1)
Ni1	0.8903 (10)	0.2033 (5)	0.2341 (3)	0.10 (4)	0.21 (1)
Mg2	0.3700 (12)	0.3748 (6)	0.2294 (4)	0.10 (4)	0.75 (1)
Ni2	0.3700 (12)	0.3748 (6)	0.2294 (4)	0.10 (4)	0.25 (1)
Mg3	0.8859 (11)	0.5255 (7)	0.2227 (3)	0.10 (4)	0.64 (1)
Ni3	0.8859 (11)	0.5255 (7)	0.2227 (3)	0.10 (4)	0.36 (1)
Si1	0.0345 (17)	0.3643 (7)	0.0402 (3)	1.47 (9)
Si2	0.5117 (19)	0.5357 (4)	0.0391 (3)	1.47 (9)
O1	0.0661 (16)	0.1944 (9)	0.9983 (6)	1.89 (9)
O2	0.2412 (19)	0.4797 (10)	0.9950 (6)	1.89 (9)
O3	0.7442 (17)	0.4241 (10)	0.0085 (5)	1.89 (9)
O4	0.027 (2)	0.3582 (15)	0.1558 (7)	1.89 (9)
O5	0.537 (2)	0.5396 (9)	0.1540 (8)	1.89 (9)
O6	0.7394 (19)	0.3702 (12)	0.2864 (4)	1.89 (9)
O7	0.226 (2)	0.1888 (15)	0.2920 (4)	1.89 (9)
O8	0.531 (2)	0.2026 (14)	0.1833 (5)	1.89 (9)
O9	0.1967 (17)	0.5346 (14)	0.2989 (4)	1.89 (9)

(Ni1.5Mg1.5Si2O5OH4) top

Crystal data top

Ni₃Mg₃Si₄O₁₈H₈	c = 14.7019 (13) Å
M_r = 648.38	β = 94.44 (2)°
Monoclinic, Cc	V = 712.29 (16) Å³
Hall symbol: C -2yc	Z = 2
a = 5.3406 (6) Å	Cu Kα radiation
b = 9.0991 (15) Å	T = 314 K

Data collection top

D2 PHASER
diffractometer

2θ_min = 5°, 2θ_max = 110°

Refinement top

R_p = 0.024

R_wp = 0.016

Special details top

Refinement. Rietveld refinement

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	B_iso*/B_eq	Occ. (<1)
Mg1	0.8910 (10)	0.2040 (7)	0.2350 (4)	0.10 (3)	0.58 (1)
Ni1	0.8910 (10)	0.2040 (7)	0.2350 (4)	0.10 (3)	0.42 (1)
Mg2	0.3687 (13)	0.3758 (7)	0.2315 (5)	0.10 (3)	0.48 (1)
Ni2	0.3687 (13)	0.3758 (7)	0.2315 (5)	0.10 (3)	0.52 (1)
Mg3	0.8863 (13)	0.5256 (6)	0.2229 (4)	0.10 (3)	0.40 (1)
Ni3	0.8863 (13)	0.5256 (6)	0.2229 (4)	0.10 (3)	0.60 (1)
Si1	0.0341 (15)	0.3644 (9)	0.0398 (4)	0.62 (7)
Si2	0.5091 (15)	0.5360 (7)	0.0386 (4)	0.62 (7)
O1	0.061 (3)	0.1935 (13)	0.9946 (10)	2.70 (9)
O2	0.243 (3)	0.4790 (17)	0.9933 (11)	2.70 (9)
O3	0.741 (3)	0.4276 (14)	0.0049 (8)	2.70 (9)
O4	0.027 (2)	0.357 (2)	0.1561 (8)	2.70 (9)
O5	0.539 (2)	0.537 (2)	0.1552 (10)	2.70 (9)
O6	0.740 (3)	0.3700 (18)	0.2861 (6)	2.70 (9)
O7	0.226 (3)	0.1860 (19)	0.2881 (6)	2.70 (9)
O8	0.531 (2)	0.202 (2)	0.1835 (8)	2.70 (9)
O9	0.196 (2)	0.534 (2)	0.2999 (6)	2.70 (9)

(Ni2MgSi2O5OH4) top

Crystal data top

Ni₄Mg₂Si₄O₁₈H₈	c = 14.6976 (11) Å
M_r = 679.77	β = 94.31 (2)°
Monoclinic, Cc	V = 713.14 (16) Å³
Hall symbol: C -2yc	Z = 2
a = 5.3415 (6) Å	Cu Kα radiation
b = 9.1095 (16) Å	T = 314 K

Data collection top

D2 PHASER
diffractometer

2θ_min = 5°, 2θ_max = 110°

Refinement top

R_p = 0.027

R_wp = 0.018

Special details top

Refinement. Rietveld refinement

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	B_iso*/B_eq	Occ. (<1)
Ni1	0.8916 (17)	0.2043 (8)	0.2354 (6)	0.10 (3)	0.63 (1)
Mg1	0.8916 (17)	0.2043 (8)	0.2354 (6)	0.10 (3)	0.37 (1)
Ni2	0.3662 (19)	0.3737 (7)	0.2333 (6)	0.10 (3)	0.57 (1)
Mg2	0.3662 (19)	0.3737 (7)	0.2333 (6)	0.10 (3)	0.43 (1)
Ni3	0.882 (2)	0.5257 (9)	0.2236 (7)	0.10 (3)	0.56 (1)
Mg3	0.882 (2)	0.5257 (9)	0.2236 (7)	0.10 (3)	0.44 (1)
Si1	0.035 (3)	0.3641 (9)	0.0391 (5)	0.15 (9)
Si2	0.521 (3)	0.5317 (8)	0.0386 (5)	0.15 (9)
O1	0.004 (3)	0.199 (2)	0.9881 (15)	3.45 (10)
O2	0.240 (4)	0.478 (4)	0.9912 (16)	3.45 (10)
O3	0.740 (4)	0.419 (2)	0.0025 (16)	3.45 (10)
O4	0.027 (4)	0.357 (3)	0.1562 (13)	3.45 (10)
O5	0.541 (4)	0.536 (3)	0.1557 (13)	3.45 (10)
O6	0.740 (4)	0.370 (2)	0.2870 (9)	3.45 (10)
O7	0.237 (4)	0.181 (3)	0.2870 (9)	3.45 (10)
O8	0.530 (3)	0.201 (3)	0.1850 (13)	3.45 (10)
O9	0.196 (3)	0.533 (3)	0.2978 (7)	3.45 (10)

(Ni3Si2O5OH4) top

Crystal data top

Ni₆Si₄O₁₈H₈	c = 14.6494 (19) Å
M_r = 742.55	β = 94.86 (2)°
Monoclinic, Cc	V = 708.87 (19) Å³
Hall symbol: C -2yc	Cu Kα radiation
a = 5.3411 (8) Å	T = 314 K
b = 9.0924 (17) Å

Data collection top

D2 PHASER
diffractometer

2θ_min = 5°, 2θ_max = 110°

Refinement top

R_p = 0.023

R_wp = 0.016

Special details top

Refinement. Rietveld refinement

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	B_iso*/B_eq
Ni1	0.8912 (10)	0.2044 (6)	0.2356 (3)	0.10 (2)
Ni2	0.3653 (11)	0.3753 (6)	0.2326 (4)	0.10 (2)
Ni3	0.8852 (14)	0.5257 (6)	0.2238 (5)	0.10 (2)
Si1	0.0339 (12)	0.3631 (10)	0.0389 (5)	0.84 (9)
Si2	0.5212 (13)	0.5381 (9)	0.0383 (5)	0.84 (9)
O1	0.976 (4)	0.2037 (16)	0.9856 (12)	3.65 (10)
O2	0.241 (3)	0.4785 (19)	0.9909 (18)	3.65 (10)
O3	0.745 (4)	0.4266 (14)	0.0055 (12)	3.65 (10)
O4	0.027 (2)	0.358 (3)	0.1562 (11)	3.65 (10)
O5	0.537 (2)	0.538 (3)	0.1553 (11)	3.65 (10)
O6	0.740 (2)	0.370 (2)	0.2870 (9)	3.65 (10)
O7	0.239 (3)	0.204 (3)	0.2853 (9)	3.65 (10)
O8	0.529 (2)	0.205 (3)	0.1892 (11)	3.65 (10)
O9	0.213 (2)	0.5538 (19)	0.3006 (8)	3.65 (10)

Format		BIBTeX
		EndNote
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		Medline
		CIF
		SGML
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Format		BIBTeX
		EndNote
		RefMan
		Refer
		Medline
		CIF
		SGML
		Text
		Plain Text

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