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Structural, optical and dielectric studies of lithium sulphate monohydrate single crystals

F.A. Najar
F.A. Najar
, 
G.B. Vakil
G.B. Vakil
 y 
B. Want
B. Want
   | 08 feb 2017
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Publicado en línea: 08 feb 2017
Páginas: 18 - 31
Recibido: 25 may 2016
Aceptado: 15 nov 2016
DOI: https://doi.org/10.1515/msp-2017-0002
Palabras clave
© 2017 F.A. Najar, G.B. Vakil, B. Want
This article is distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

ORTEP view of a molecule showing the atomlabeling scheme.
ORTEP view of a molecule showing the atomlabeling scheme.

The packing arrangement of molecules viewed down the b-axis.
The packing arrangement of molecules viewed down the b-axis.

Morphology of LSMH crystal (a) as grown and (b) predicted by BFDH model.
Morphology of LSMH crystal (a) as grown and (b) predicted by BFDH model.

Optical transmittance and reflectance spectra for LSMH crystal.
Optical transmittance and reflectance spectra for LSMH crystal.

Tauc’s plot and variation of absorption coefficient with wavelength for LSMH crystal.
Tauc’s plot and variation of absorption coefficient with wavelength for LSMH crystal.

Ft-Ir Spectrum For Lsmh Crystal.
Ft-Ir Spectrum For Lsmh Crystal.

Variation of real part of dielectric constant (∊′) versus temperature for LSMH crystal.
Variation of real part of dielectric constant (∊′) versus temperature for LSMH crystal.

TGA/DTG curve of LSMH crystal.
TGA/DTG curve of LSMH crystal.

Variation of dielectric loss (D) versus temperature for LSMH crystal.
Variation of dielectric loss (D) versus temperature for LSMH crystal.

Variation of real part of dielectric constant (∊′) versus logf (Hz) for LSMH crystal.
Variation of real part of dielectric constant (∊′) versus logf (Hz) for LSMH crystal.

Variation of dielectric loss (D) with logf (Hz) for LSMH crystal.
Variation of dielectric loss (D) with logf (Hz) for LSMH crystal.

Plot of logχ versus logω for LSMH crystal.
Plot of logχ versus logω for LSMH crystal.

Variation of AC conductivity versus temperature for LSMH crystal.
Variation of AC conductivity versus temperature for LSMH crystal.

Plot of ln σac versus 1000/T at 1 kHz for LSMH crystal.
Plot of ln σac versus 1000/T at 1 kHz for LSMH crystal.

Plot of σac versus lnω for LSMH crystal.
Plot of σac versus lnω for LSMH crystal.

Plot of lnσac versus lnω for LSMH crystal at temperature of 50 °C.
Plot of lnσac versus lnω for LSMH crystal at temperature of 50 °C.

Vickers hardness number against load for LSMH crystal.
Vickers hardness number against load for LSMH crystal.

logp versus logd for LSMH crystal.
logp versus logd for LSMH crystal.

Crystallographic and experimental data.

Crystal descriptionwhite block
Crystal size0.5 mm3 × 0.3 mm3 × 0.2 mm3
Empirical formulaH2Li2O5S
Formula weight127.96 g
Radiation, wavelengthMoKα, 0.71073 Å
Unit cell dimensionsa = 5.4512(8) Å, b = 4.8726(6) Å, c = 8.1724(10) Å, α = 90°, β = 107.291° (3), = 90°
Crystal systemmonoclinic
Space groupP 21
Unit cell volume207.26(5) Å−3
No. of molecules per unit cell, Z2
Temperature296(2) K
Absorption coefficient0.676 mm−1
F(0 0 0)128
Scan modeω scan
θ range for entire data collection2.61° < θ < 28.32°
Range of indicesh = −6 to 5, k = −6 to 6.1 = −10 to 10
Reflections collected/unique1348/453
Reflections observed(I > 2σ (I)) 451
Rint0.0206
Rsigma0.0193
Structure determinationDirect methods
RefinementFull-matrix least-squares on F2
No. of parameters refined82
Final R0.0174
wR(F2)0.0472
Weight1/[σ2(Fo2)+(0.0286P)2+0.0218P]whereP=[Fo2+2Fc2]/3$ 1/[\sigma^2( {\text F_\text o^2} ) + (0.0286\text P)^2 + 0.0218\text P]\,\,\,\text {where} \,\,\,\text P = [ {\text F_\text o^2} + 2 {\text F_\text c^2} ]/3$
Goodness-of-fit1.287
Final residual electron density−0.308 eÅ−3 < Δρ < 0.161 eÅ−3

Force constant (k) values for different vibrations of LSMH crystals.

Frequency [cm−1]Vibrational assignmentForce constant k [N/m]
3471O–H stretching643
1614S–O stretching1575
1095S–O stretching725

Bond lengths [Å], bond angles [°] and torsion angles for LSMH atoms (e.s.d.’s are given in parentheses).

Bond distances
S1–O11.4774(16)S1–O21.4734(16)
S1–O31.4598(16)S1–O41.475(2)
O1–Li11.950(4)O2–Li21.957(5)
Li1–05ix1.905(4)O5–H20.89(6)
O5–H10.64(5)
Bond angles
O4–S1–O2108.88(10)O2–S1–O1108.88(10)
O3–S1–O2110.14(10)O3–S1–O4110.56(10)
O4–S1–O1108.89(10)O3–S1–O1109.46(10)
S1–O2–Li2120.33(14)S1–O1–Li1119.02(14)
O5ix–Li1–O1107.1(2)Li1–O5–H1133(5)
Li1–O5–H2106(3)H2–O5–H1115(6)
Torsion angles
O3–S1–O2–Li2–41.44(18)
O4–S1–O2–Li2–162.82(15)
O4–S1–O1–Li1ii48.0(2)
O3–S1–O1–Li1ii–73.0(2)
S1–O1–Li1–O5ix95.49(19)

Intermolecular hydrogen bonding of the O–H…O type.

D–H… AD–HH…AD… AD–H… A
[Å][Å][Å][°]
O5–H1…O3i0 652.302.90155
O5–H2… O5ii0.892.112.96161

Calculated data for LSMH single crystal.

ParametersValues
Plasma energy [eV]18.86
Penn gap [eV]8.0
Fermi energy [eV]14.80
Polarizability [cm−3] using Penn analysis1.6 × 10−23
Polarizability [cm−3] using Clausius-Mossoti equation1.68 × 10−23
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