CATIONIC SELF-DIFFUSION IN THE HIGHEST-TEMPERATURE SOLID-PHASES OF AMMONIUM-CHLORIDE AND BROMIDE STUDIED BY H-1-NMR

被引：22

作者：

TANSHO, M ^{[1
]}

FURUKAWA, Y ^{[1
]}

NAKAMURA, D ^{[1
]}

IKEDA, R ^{[1
]}

机构：

[1] UNIV TSUKUBA,DEPT CHEM,TSUKUBA 305,JAPAN

来源：

BERICHTE DER BUNSEN-GESELLSCHAFT-PHYSICAL CHEMISTRY CHEMICAL PHYSICS | 1992年 / 96卷 / 04期

关键词：

CRYSTALS; DIFFUSION; PHASE TRANSITIONS; SPECTROSCOPY; NUCLEAR MAGNETIC RESONANCE;

D O I：

10.1002/bbpc.19920960407

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Ionic motions in the highest-temperature solid phases (Phase I) of NH4Cl and NH4Br having the NaCl-type cubic structure were investigated by measuring H-1 NMR spin-lattice and spin-spin relaxation times (T1, T1-rho and T2). A long T2 of ca. 1 ms observed at 750 K in Phase I of both salts was attributed to the excitation of the rapid cationic self-diffusion and isotropic rotation suggesting the plastic nature of this phase. The observed relaxation times could be explained well using the monovacancy-diffusion model proposed by Sholl. The activation energy of self-diffusion was determined as 120 kJ mol-1 for both salts, which value is much larger than those observed in ionic-plastic phases with the CsCl-type cubic structure. The diffusion mechanisms of the NH4+ ions in Phase I, and Phase II having the CsCl-type structure, were compared.

引用

页码：550 / 553

页数：4

共 27 条

[1] ABRAGAM A, 1961, PRINCIPLES NUCLEAR M
[2] The crystal structures of the ammonium halides above and below the transition temperatures.
Bartlett, G
Langmuir, I
[J]. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1921, 43 : 84 - 91
[3] NUCLEAR-SPIN RELAXATION BY TRANSLATIONAL DIFFUSION IN SOLIDS .3. DIFFUSION IN FCC, BCC AND SC SINGLE-CRYSTALS
BARTON, WA
SHOLL, CA
[J]. JOURNAL OF PHYSICS C-SOLID STATE PHYSICS, 1976, 9 (23): : 4315 - 4328
[4] ON MECHANISM OF THERMAL TRANSFORMATIONS IN SOLID AMMONIUM NITRATE
BROWN, RN
MCLAREN, AC
[J]. PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON SERIES A-MATHEMATICAL AND PHYSICAL SCIENCES, 1962, 266 (1326): : 329 - &
[5] SYMMETRY OF PARAELECTRIC DEFECTS IN ALKALI HALIDES
BYER, NE
SACK, HS
[J]. PHYSICAL REVIEW LETTERS, 1966, 17 (02) : 72 - &
[6] DIFFUSION IN MOLECULAR-CRYSTALS
CHEZEAU, JM
STRANGE, JH
[J]. PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS, 1979, 53 (01): : 1 - 92
[7] CL-35 NQR AND H-1-NMR STUDIES OF [C(NH2)3]AUCL4, [C(NH2)3]2PTCL4, AND [C(NH2)3]2PDCL4
GIMA, SE
FURUKAWA, Y
IKEDA, R
NAKAMURA, D
[J]. JOURNAL OF MOLECULAR STRUCTURE, 1983, 111 (DEC) : 189 - 194
[8] HAVEN Y, 1958, PHILIPS TECH REV, V20, P69
[9] THEORY OF NUCLEAR MAGNETIC RELAXATION BY SPIN-ROTATIONAL INTERACTIONS IN LIQUIDS
HUBBARD, PS
[J]. PHYSICAL REVIEW, 1963, 131 (03): : 1155 - &
[10] SPIN-ROTATIONAL RELAXATION FOR PROTONS IN SOLID NH4CLO4
IKEDA, R
MCDOWELL, CA
[J]. CHEMICAL PHYSICS LETTERS, 1972, 14 (04) : 389 - &

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