투고논문
| JKMRS Volume 23, No 2, pp 40, Thermodynamic and Physical Prope... | |
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| 2019년 09월 22일 / 조회수: 566 | |
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Thermodynamic and Physical Properties of (NH4)2MnCl4∙2H2O by Nuclear Magnetic Resonance Relaxation Times
Yoo Young Kim *
Department of Science Education, Jeonju University, Jeonju 55069, South Korea
Received May 23, 2019; Revised May 31, 2019; Accepted May 31, 2019
Abstract The phase transition temperatures and thermodynamic properties of (NH4)2MnCl4∙2H2O grown by the slow evaporation method were studied using differential scanning calorimetry and thermogravimetric analysis. A structural phase transition occurred at temperature TC1 (=264 K), whereas the changes at TC2 (=460 K) and TC3 (=475 K) seemed to be chemical changes caused by thermal decomposition. In addition, the chemical shift and the spin-lattice relaxation time T1ρ were investigated using 1H magic-angle spinning nuclear magnetic resonance (MAS NMR), in order to understand the role of NH4+ and H2O. The rise in T1ρ with temperature was related to variations in the symmetry of the surrounding H2O and NH4+.
Keywords (NH4)2MnCl4∙2H2O, crystal growth, thermodynamic property, phase transition, nuclear magnetic resonance
* Address correspondence to: Yoo Young Kim, Dept. of Science Education, Jeonju University, 303 Chenjam-ro, Wansan-gu, Jeonju-si, 55069, South Korea, Tel: 82-63-220-2554; Fax: 82-63-220-2053; E-mail: yooykim@jj.ac.kr
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| 첨부파일 | 1_YYKim_final.pdf |