Synthesis and Spectrophotometric Properties of Sodium Metal Carboxylates
Iortyom Susan Doofan,
Kukwa Donald,
Iornumbe Esther Nguumbur,
Agbidye Isaac Gbaa,
Ijuo Godwin
Issue:
Volume 9, Issue 5, October 2021
Pages:
113-120
Received:
28 July 2021
Accepted:
18 August 2021
Published:
6 September 2021
Abstract: While metal carboxylates are by no means rare or inaccessible, complete characterization with notable exception of acetates is largely neglected hence a deficiency within the carboxylate literature giving rise to discrepancies within the characterization data available thus, spectroscopic properties of synthesized sodium metal carboxylates of acetic acid and myristic acid were investigated using Atomic Absorption Spectroscopy (AAS), flame photometry, FTIR spectrophotometer and UV- Visible spectrophotometry. AAS and flame photometric results showed elemental abundance of the sodium metals in the carboxylate complexes. FTIR spectra data revealed ʋCOO- absorptions at 1636 cm-1 and 1558 cm-1 for sodium acetate and sodium myristate respectively. The free acid ligands showed absorptions at 1703 cm-1 for acetic acid which shifted to 1636 cm-1 for sodium acetate. FTIR absorption of myristic acid revealed a strong absorption band at 1696 cm-1 which shifted to 1558 cm-1 in sodium myristate. The geometry of the complexes were determined by the magnitude of separation, Δʋ, which is equal to ʋaym - ʋsym,. The values of Δʋ for the synthesized sodium acetate complex was found to be 231 cm-1 and 138 cm-1 for sodium myristate indicating monodentate and bridging bidentate bonding respectively. Force constants of the carboxylates which correspond to their bond energies were found to be 1495.94 K NM-1 and 1358 K NM-1 for sodium acetate and sodium myristate, respectively. The UV- Visible analysis shows ʎ max values of 201 nm and 195 nm for sodium acetate and sodium myristate respectively, which corresponds to the absorption of the COO chromophore which is due to n-π* transition.
Abstract: While metal carboxylates are by no means rare or inaccessible, complete characterization with notable exception of acetates is largely neglected hence a deficiency within the carboxylate literature giving rise to discrepancies within the characterization data available thus, spectroscopic properties of synthesized sodium metal carboxylates of aceti...
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Residual Elastic Stress in Historical Coins as a Criterion for Authentication
Alexander Joseph Kossolapov,
Ksenia Sergeevna Chugunova
Issue:
Volume 9, Issue 5, October 2021
Pages:
121-128
Received:
20 August 2021
Accepted:
4 September 2021
Published:
10 September 2021
Abstract: Authentication of coins is frequently presenting complicated problem in numismatics practice. Metal composition only may not be enough to identify forgeries, notably when one deals with noble metals – silver, gold or electron. Isotopic ratios, providing in certain cases information regarding metallic ore source (geographical provenance), require a sample to be extracted for MS-analysis while sampling is not permissible for numismatic material in principle. To solve the problem it becomes crucial, in addition to metal’s composition, to establish the method used for a coin’s manufacturing, as forgers are rarely realizing or following the method that was used in the original historical production. Conventional visual studying under microscope is not always being enough to understand how the coin was produced while metallographic examination of polished and etched metal samples, which might provide necessary information, is not applicable here for its destructive character. Necessary information regarding manufacturing could have been extracted from residual stress analysis, but, in general, there were very few published works regarding this kind of analysis for coins, and those few did not consider any connection between manufacturing process and residual stress in metal. The expected types of residual elastic stress arisen under historically known methods of coins production (casting in hot or cold mold, striking hot or cold metal) are considered in this work. On this base, non-destructive X-rays diffraction method (Sin2Ψ-method) is offered to distinguish between various methods of manufacturing. The results may be applied in museum’s laboratory as useful criterion for authentication of coins and medals.
Abstract: Authentication of coins is frequently presenting complicated problem in numismatics practice. Metal composition only may not be enough to identify forgeries, notably when one deals with noble metals – silver, gold or electron. Isotopic ratios, providing in certain cases information regarding metallic ore source (geographical provenance), require a ...
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