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A hitherto unknown phase of sodium titanate, NaTi3O6(OH)·2H2O, was identified as the intermediate species in the synthesis of TiO2 nanorods. This new phase, prepared as nanorods, was investigated by electron diffraction, X-ray powder diffraction, thermogravimetric analysis and high-resolution transmission electron microscopy. The structure was determined ab initio using electron diffraction data collected by the recently developed automated diffraction tomography technique. NaTi3O6(OH)·2H2O crystallizes in the monoclinic space group C2/m. Corrugated layers of corner- and edge-sharing distorted TiO6 octahedra are intercalated with Na+ and water of crystallization. The nanorods are typically affected by pervasive defects, such as mutual layer shifts, that produce diffraction streaks along c*. In addition, edge dislocations were observed in HRTEM images.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108768111014534/kd5050sup1.cif
Contains datablocks global, I

rtv

Rietveld powder data file (CIF format) https://doi.org/10.1107/S0108768111014534/kd5050Isup2.rtv
Contains datablock I

fcf

Structure factor file (CIF format) https://doi.org/10.1107/S0108768111014534/kd5050Isup3.fcf
Contains datablock I

Computing details top

Program(s) used to solve structure: Sir2008; program(s) used to refine structure: SHELXL97.

Figures top
[Figure 1]
[Figure 2]
[Figure 3]
[Figure 4]
[Figure 5]
[Figure 6]
[Figure 7]
(I) top
Crystal data top
NaO3Ti1.25Z = 8
Mr = 130.86F(000) = 173
Monoclinic, C2/MDx = 2.587 Mg m3
a = 21.555 (7) ÅElectron radiation, λ = 0.0197 Å
b = 3.7583 (9) ŵ = 0.01 mm1
c = 11.926 (5) ÅT = 295 K
β = 136.14 (2)°Elongated wire
V = 669.5 (4) Å31.0 × 0.05 × 0.05 mm
Data collection top
FEI TECNAI F-30 S-TWIN TEM with automated diffraction topography (ADT) and precession electron diffraction (PED) attachments
diffractometer
θmax = 0.7°, θmin = 0.1°
Not monochromatorh = 2626
1749 measured reflectionsk = 44
628 independent reflectionsl = 1414
Rint = 0.158
Refinement top
Refinement on F20 restraints
Least-squares matrix: fullPrimary atom site location: structure-invariant direct methods
R[F2 > 2σ(F2)] = 0.267Secondary atom site location: difference Fourier map
wR(F2) = 0.592 w = 1/[σ2(Fo2) + (0.1P)2]
where P = (Fo2 + 2Fc2)/3
S = 3.73(Δ/σ)max = 0.863
628 reflectionsΔρmax = 0.73 e Å3
40 parametersΔρmin = 0.51 e Å3
Crystal data top
NaO3Ti1.25V = 669.5 (4) Å3
Mr = 130.86Z = 8
Monoclinic, C2/MElectron radiation, λ = 0.0197 Å
a = 21.555 (7) ŵ = 0.01 mm1
b = 3.7583 (9) ÅT = 295 K
c = 11.926 (5) Å1.0 × 0.05 × 0.05 mm
β = 136.14 (2)°
Data collection top
FEI TECNAI F-30 S-TWIN TEM with automated diffraction topography (ADT) and precession electron diffraction (PED) attachments
diffractometer
628 independent reflections
1749 measured reflectionsRint = 0.158
Refinement top
R[F2 > 2σ(F2)] = 0.2670 restraints
wR(F2) = 0.592(Δ/σ)max = 0.863
S = 3.73Δρmax = 0.73 e Å3
628 reflectionsΔρmin = 0.51 e Å3
40 parameters
Special details top

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 (Å2) top
xyzUiso*/Ueq
Ti10.7514 (4)0.00000.3943 (9)0.029 (2)*
Ti20.5712 (5)0.50000.5130 (11)0.036 (2)*
Ti30.5764 (4)0.00000.3019 (9)0.028 (2)*
O10.7286 (9)0.00000.537 (2)0.024 (3)*
O20.6272 (13)0.00000.222 (3)0.049 (5)*
OW10.3705 (12)0.00000.158 (3)0.048 (5)*
O30.7073 (10)0.50000.692 (2)0.035 (4)*
O40.6009 (10)0.50000.370 (2)0.035 (4)*
O50.5691 (11)0.50000.668 (2)0.044 (5)*
O60.5637 (10)0.00000.452 (2)0.033 (4)*
Na20.7682 (11)0.00000.916 (3)0.052 (4)*
OW20.9124 (14)0.00000.950 (3)0.067 (7)*
OH0.4636 (9)0.00000.119 (2)0.031 (4)*
Geometric parameters (Å, º) top
Ti1—O3i1.775 (19)Ti3—O62.00 (2)
Ti1—O21.85 (2)Ti3—O21.90 (2)
Ti1—O1ii1.983 (5)O1—Ti1ii1.983 (5)
Ti1—O1i1.983 (5)O1—Ti1i1.983 (5)
Ti1—O12.086 (18)OW1—Na2vi2.42 (3)
Ti2—O51.88 (2)O3—Ti1i1.775 (19)
Ti2—O5iii2.088 (18)O4—Ti3iv1.978 (5)
Ti2—O6iv1.993 (7)O5—Ti2iii2.088 (18)
Ti2—O61.993 (7)O6—Ti2v1.993 (7)
Ti2—O32.025 (16)Na2—OW1vi2.42 (3)
Ti3—OH1.731 (16)Na2—Na2vii3.23 (3)
Ti3—O4v1.978 (6)Na2—Na2viii3.23 (3)
Ti3—O41.978 (5)
O3i—Ti1—O2106.4 (10)O4v—Ti3—O4146.8 (11)
O3i—Ti1—O1ii100.8 (5)OH—Ti3—O698.7 (8)
O2—Ti1—O1ii99.6 (4)O4v—Ti3—O678.4 (6)
O3i—Ti1—O1i100.8 (5)O4—Ti3—O678.4 (6)
O2—Ti1—O1i99.6 (4)OH—Ti3—O299.3 (9)
O1ii—Ti1—O1i145.7 (10)O4v—Ti3—O297.3 (6)
O3i—Ti1—O1169.1 (7)O4—Ti3—O297.3 (6)
O2—Ti1—O184.5 (8)O6—Ti3—O2162.0 (9)
O1ii—Ti1—O176.9 (5)Ti1ii—O1—Ti1i145.7 (10)
O1i—Ti1—O176.9 (5)Ti1ii—O1—Ti1103.1 (5)
O5—Ti2—O5iii88.2 (8)Ti1i—O1—Ti1103.1 (5)
O5—Ti2—O6iv107.7 (6)Ti1—O2—Ti3109.6 (12)
O5iii—Ti2—O6iv87.0 (5)Ti1i—O3—Ti2110.0 (10)
O5—Ti2—O6107.7 (6)Ti3—O4—Ti3iv146.8 (11)
O5iii—Ti2—O687.0 (5)Ti2—O5—Ti2iii91.8 (8)
O6iv—Ti2—O6143.9 (12)Ti2v—O6—Ti2143.9 (12)
O5—Ti2—O390.7 (8)Ti2v—O6—Ti3107.3 (6)
O5iii—Ti2—O3179.0 (9)Ti2—O6—Ti3107.3 (6)
O6iv—Ti2—O393.3 (5)OW1vi—Na2—Na2vii56.0 (6)
O6—Ti2—O393.3 (5)OW1vi—Na2—Na2viii56.0 (6)
OH—Ti3—O4v103.4 (5)Na2vii—Na2—Na2viii71.8 (9)
OH—Ti3—O4103.4 (5)
Symmetry codes: (i) x+3/2, y1/2, z+1; (ii) x+3/2, y+1/2, z+1; (iii) x+3/2, y1/2, z+1; (iv) x, y1, z; (v) x, y+1, z; (vi) x+3/2, y+1/2, z+1; (vii) x+3/2, y+1/2, z+2; (viii) x+3/2, y1/2, z+2.

Experimental details

Crystal data
Chemical formulaNaO3Ti1.25
Mr130.86
Crystal system, space groupMonoclinic, C2/M
Temperature (K)295
a, b, c (Å)21.555 (7), 3.7583 (9), 11.926 (5)
β (°) 136.14 (2)
V3)669.5 (4)
Z8
Radiation typeElectron, λ = 0.0197 Å
µ (mm1)0.01
Crystal size (mm)1.0 × 0.05 × 0.05
Data collection
DiffractometerFEI TECNAI F-30 S-TWIN TEM with automated diffraction topography (ADT) and precession electron diffraction (PED) attachments
diffractometer
Absorption correction
No. of measured, independent and
observed (?) reflections
1749, 628, ?
Rint0.158
(sin θ/λ)max1)0.620
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.267, 0.592, 3.73
No. of reflections628
No. of parameters40
(Δ/σ)max0.863
Δρmax, Δρmin (e Å3)0.73, 0.51

Computer programs: Sir2008, SHELXL97.

 

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