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The Diffusion of Mercury in Purified KCl and the Effect of OH − on Diffusion
Author(s) -
Allen C. A.,
Fredericks W. J.
Publication year - 1973
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2220550217
Subject(s) - mercury (programming language) , hydroxide , chemistry , ion , vacancy defect , analytical chemistry (journal) , diffusion , atmospheric temperature range , solubility , activation energy , doping , inorganic chemistry , crystallography , thermodynamics , materials science , chromatography , organic chemistry , optoelectronics , computer science , physics , programming language
The diffusion of mercury into both purified and hydroxide doped Kci was studied. The high vapor pressure of HgCI 2 required modification of the usual technique to assure constant boundary conditions. The very low solubility of mercury made accurate determination of diffusion parameters difficult. Mercury diffuses into purified KCI over the temperature range from 449 to 549 °C in accordance with the relation D s = 8.18 × 10 −5 exp (−0.57 eV/kT). Over this same temperature range the free energy of association for the mercuric ion‐cation vacancy complex varies from 0.75 to 0.80 eV, an abnormally large value for this type of association. The presence of OH‐ causes extreme distortion of the concentration‐distance curve by forming a maximum in mercury concentration well away from the surface of the crystal. The maximum is thought to arise from the formation of the mercuric ion‐hydroxide ion compound identified optically in earlier studies.