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

Crystal description	white block
Crystal size	0.5 mm³ × 0.3 mm³ × 0.2 mm³
Empirical formula	H₂Li₂O₅S
Formula weight	127.96 g
Radiation, wavelength	MoKα, 0.71073 Å
Unit cell dimensions	a = 5.4512(8) Å, b = 4.8726(6) Å, c = 8.1724(10) Å, α = 90°, β = 107.291° (3), = 90°
Crystal system	monoclinic
Space group	P 2₁
Unit cell volume	207.26(5) Å⁻³
No. of molecules per unit cell, Z	2
Temperature	296(2) K
Absorption coefficient	0.676 mm⁻¹
F(0 0 0)	128
Scan mode	ω scan
θ range for entire data collection	2.61° < θ < 28.32°
Range of indices	h = −6 to 5, k = −6 to 6.1 = −10 to 10
Reflections collected/unique	1348/453
Reflections observed	(I > 2σ (I)) 451
R_int	0.0206
R_sigma	0.0193
Structure determination	Direct methods
Refinement	Full-matrix least-squares on F²
No. of parameters refined	82
Final R	0.0174
wR(F²)	0.0472
Weight	$1 / [σ^{2} (F_{o}^{2}) + (0.0286 P)^{2} + 0.0218 P] where P = [F_{o}^{2} + 2 F_{c}^{2}] / 3$
Goodness-of-fit	1.287
Final residual electron density	−0.308 eÅ⁻³ < Δρ < 0.161 eÅ⁻³

Table 2

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

Bond distances

S1–O1	1.4774(16)	S1–O2	1.4734(16)
S1–O3	1.4598(16)	S1–O4	1.475(2)
O1–Li1	1.950(4)	O2–Li2	1.957(5)
Li1–05^ix	1.905(4)	O5–H2	0.89(6)
O5–H1	0.64(5)

Bond angles

O4–S1–O2	108.88(10)	O2–S1–O1	108.88(10)
O3–S1–O2	110.14(10)	O3–S1–O4	110.56(10)
O4–S1–O1	108.89(10)	O3–S1–O1	109.46(10)
S1–O2–Li2	120.33(14)	S1–O1–Li1	119.02(14)
O5^ix–Li1–O1	107.1(2)	Li1–O5–H1	133(5)
Li1–O5–H2	106(3)	H2–O5–H1	115(6)

Torsion angles

O3–S1–O2–Li2	–41.44(18)
O4–S1–O2–Li2	–162.82(15)
O4–S1–O1–Li1ⁱⁱ	48.0(2)
O3–S1–O1–Li1ⁱⁱ	–73.0(2)
S1–O1–Li1–O5^ix	95.49(19)

Symmetry: (i) x, 1 + y, z; (ii) 1 – x, 0.5 + y, 2 – z; (iii) 1 – x, 0.5 + y, 1 – z; (iv) –x, 0.5 + y, 1 – z; (v) –1 + x, y, z; (vi) –x, –0.5 + y, 1 – z; (vii) 1 – x, –0.5 + y, 1 – z; (viii) x, –1 + y, z; (ix) 1 + x, y, z; (x) 1 – x, –0.5 + y, 2 – z.

Table 3

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

D–H… A	D–H	H…A	D… A	D–H… A
	[Å]	[Å]	[Å]	[°]

O5–H1…O3ⁱ	0 65	2.30	2.90	155
O5–H2… O5ⁱⁱ	0.89	2.11	2.96	161

Symmetry: (i) x – 1, y, z (ii) –x, y – 1/2, –z

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

Table 4

Calculated data for LSMH single crystal.

Parameters	Values

Plasma energy [eV]	18.86
Penn gap [eV]	8.0
Fermi energy [eV]	14.80
Polarizability [cm⁻³] using Penn analysis	1.6 × 10⁻²³
Polarizability [cm⁻³] using Clausius-Mossoti equation	1.68 × 10⁻²³

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

Optical transmittance and reflectance spectra for LSMH crystal.

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

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

Table 5

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

Frequency [cm⁻¹]	Vibrational assignment	Force constant k [N/m]
3471	O–H stretching	643
1614	S–O stretching	1575
1095	S–O stretching	725

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

Plot of logχ versus logω for LSMH crystal.

Variation of AC conductivity versus temperature for LSMH crystal.

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

Plot of σ_ac versus lnω for LSMH crystal.

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

Vickers hardness number against load for LSMH crystal.

References

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DOI: https://doi.org/10.1515/msp-2017-0002 | Journal eISSN: 2083-134X (formerly 2083-124X) | Journal ISSN: 2083-1331

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Language: English

Page range: 18 - 31

Submitted on: May 25, 2016

Accepted on: Nov 15, 2016

Published on: Feb 8, 2017

Published by: Wroclaw University of Science and Technology

In partnership with: Paradigm Publishing Services

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Related subjects:

Materials sciences, other,

Nanomaterials,

Functional and smart materials,

Materials characterization and properties

© 2017 F.A. Najar, G.B. Vakil, B. Want, published by Wroclaw University of Science and Technology
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Volume 35 (2017): Issue 1 (March 2017)