2. Synthesis, crystal structure and optical characterization of sulfide
chloride oxide (CsBa₆V₄S₁₂ClO₄) with a near infrared
fluorescence.
Presented by:
Amiza
Presented to:
Dr. Sohail Nadeem
Advanced inorganic chemistry
5. Jens
Martensson
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When CsCl, BaS, BaO, V, and S are reacted in a solid-state reaction under inert
conditions, pure powders and single crystals of senary CsBa₆V₄S₁₂ClO₄ can be
obtained. Its unique crystal structure has;
• Symmetry R3̅H
• Unit cell parameters a = 9.0575(2) and c = 28.339(1) Å.
The crystal structure contains polar units [VS₃O]³⁻ and a complex BaS₇ClO₂
coordination.
The compound gets its deep-red color from a low-energy charge transfer, which can
be explained by an electron transfer from S⁻² to V⁺⁵.
In the near-infrared range, down-converted fluorescence occurs at 1.06 and 0.90 eV,
and both emissions appear <450 ps after excitation at about 1.27 eV ¹.
Abstract
6. Jens
Martensson
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A recently popularized route to synthesize novel
inorganic compounds involves the combination of two
anions that form ordered lattices other than classic close-
packing structures.
These fundamentally different assemblies of anions
allow for cations to be either coordinated by one type of
anion (homoleptically) or by two different anions
(heteroleptically).
Introduction
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Martensson
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Conti….
• Heteroleptical coordination gives rise to rare and
novel physical situations and occurs frequently in
bichalcogenides.
• The sulfide-oxides are most investigated because,
their tetrahedral heteroleptic coordination have
extensive flexibility ².
9. Jens
Martensson
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Obtained crystallites are transparent and have deep-red color.
The obtained samples contain crystallites of up to about 0.5 mm that turn into a dark-red
powder upon grinding.
Scanning electron microscope reveal the plate-like crystallites possess edges with
characteristic angles close to 30° and 120°, agreeing with trigonal, hexagonal, and
rhombohedral symmetries.
Basic properties ¹
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Martensson
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By using the shortest Ba−S, V−S, and V−O interatomic distances, it is possible to
discern crystal structure building blocks:
[Ba₆Cl]⁺¹¹
[VS₃O]⁻³
The polar [VS₃O]⁻³ tetrahedral entities are arranged with their O vertices along the
crystallographically unique axis (c), but the space group inversion symmetry cancels
the global polarity as the number of “up” polarities equals the “down” polarities.
The interatomic distance between Ba−Cl in [Ba₆Cl]⁺¹¹ is 3.4369(3) Å . The
interatomic distance between V−S is 2.160 (1) and V−O is 1.693(5) Å in [VS₃O]⁻³.
Crystal structure ³
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Martensson
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(a) Crystal structure of CsBa₆V₄S₁₂ClO₄ in perspective view with outlined unit cell. ((b)
Four selected cation coordinations with interatomic distances in angstroms.
(a) (b)
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Martensson
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Absorption spectrum of CsBa₆V₄S₁₂ClO₄
Optical absorption of senary
compound reveal the reason for
strong sample coloring;
• Typical charge transfer at about 2 eV.
• Ligand to metal electron transfer, S²⁻
to V⁵⁺.
With respect to measured baseline,
title compound exhibit intrinsic
optical feature in near infrared (NIR)
range (0.90 − 1.25 eV).
Optical properties ⁴
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Martensson
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• Upon exposure of laser light
(1.28 eV) on the sample
photoluminescence occurs.
• Two broad peaks obtained
which indicate weak
fluorescence in NIR energy
range.
First peak 0.90 eV
Second peak 1.06 eV
Photoluminescence spectra ¹
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Martensson
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• Sharp peaks obtained having
high intensity
• These peaks show higher
position accuracy.
Powder X-ray diffraction ⁵
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Martensson
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By solid-state reaction, it is possible to obtain the senary compound (CsBa₆V₄S₁₂ClO₄)
as both pure powder and small single crystals.
The centrosymmetric crystal structure contains polar units [VS₃O]⁻³ and a complex
BaS₇ClO₂ coordination.
Both powder and single crystals are strongly colored red depending on the low-energy
charge transfer, presumably from S²⁻to V⁵⁺.
An extremely short-lived (<450 ps) fluorescence occurs as down-conversion and the
emissions appear doubly at about 1.06 eV and, presumably, singly at 0.90 eV.
Conclusion
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Martensson
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1. Valldor, M., Galle, L., Eichler, F., Wolf, A., & Morrow, R. (2019). Synthesis, Crystal Structure, and
Optical Characterization of the Sulfide Chloride Oxide CsBa₆V₄S₁₂ClO₄ with a Near-Infrared
Fluorescence. Inorganic Chemistry, 58(21), 14728-14733.
2. Valldor, M. (2016). Anion ordering in bichalcogenides. Inorganics, 4(3), 23.
3. Trojer, F. J. (1966). Refinement of the structure of sulvanite. American Mineralogist: Journal of Earth
and Planetary Materials, 51(5-6), 890-894.
4. Schnabel, S., & Röhr, C. (2008). Kalium-Thio/Oxo-Vanadate (V) K₃ [VSxO₄–x](x= 1–4) und
Na₃[VSO₃]: Synthese, Strukturchemie, Eigenschaften. Zeitschrift für Naturforschung B, 63(7), 819-833.
5. Petříček, V., Dušek, M., & Palatinus, L. (2014). Crystallographic computing system JANA2006:
general features. Zeitschrift für Kristallographie-Crystalline Materials, 229(5), 345-352.
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