ABSTRACT
Generally, 88% of the freshly generated 218Po ions decayed from 222Rn are positively charged. These positive ions become neutralized by recombination with negative ions, and the main source of the negative ions is the OH- ions formed by radiolysis of water vapor. However, the neutralization rate of positively charged 218Po versus the square root of the concentration of H2O will be a constant when the concentration of H2O is sufficiently high. Since the electron affinity of the hydroxyl radical formed by water vapor is high, the authors propose that the hydroxyl radical can grab an electron to become OH-. Because the average period of collision with other positively charged ions and the average life of the OH- are much longer than those of the electron, the average concentration of negative ions will grow when the water vapor concentration increases. The authors obtained a model to describe the growth of OH- ions. From this model, it was found that the maximum value of the OH- ion concentration is limited by the square root of the radon concentration. If the radon concentration is invariant, the OH- ion concentration should be approximately a constant when the water vapor concentration is higher than a certain value. The phenomenon that the neutralization rate of positively charged 218Po versus the square root of the water vapor concentration will be saturated when the water vapor concentration is sufficiently high can be explained by this mechanism. This mechanism can be used also to explain the phenomenon that the detection efficiency of a radon monitor based on the electrostatic collection method seems to be constant when the water vapor concentration is high.
Subject(s)
Polonium/chemistry , Radiochemistry , Water/chemistry , Hydroxides/chemistry , Radon/chemistry , VolatilizationABSTRACT
The title heteronuclear complex, {[AgHo(C(14)H(8)N(2)O(5))(2)(H(2)O)]·2H(2)O}(n), has a three-dimensional polymeric structure, generated by the carboxyl-ate and pyridine groups of the 5-(isonicotinamido)-isophthalate (INAIP) ligands bridging the metal atoms. The Ho(III) atom is coordinated by seven O atoms from INAIP ligands and a water mol-ecule in a distorted square-anti-prismatic geometry, while the Ag(I) atom has a distorted trigonal-planar AgN(2)O geometry. Inter-molecular O-Hâ¯O and N-Hâ¯O hydrogen bonds stabilize the crystal structure.
ABSTRACT
The 4d-4f heteronuclear title complex, [AgCe(C(14)H(8)N(2)O(5))(2)(H(2)O)](n), has a three-dimensional framework structure, generated by the carboxyl-ate and pyridyl groups of the 5-(isonicotinamido)-isophthalate (INAIP) ligands bridging the metal ions. The Ce(III) atom is coordinated by eight O atoms from six INAIP ligands and a water mol-ecule in a distorted tricapped trigonal-prismatic geometry, while the Ag(I) atom has a distorted trigonal-planar AgN(2)O geometry. O-Hâ¯O and N-Hâ¯O hydrogen bonds and π-π inter-actions between the pyridine and benzene rings [centroid-centroid distances = 3.642â (4) and 3.624â (3)â Å] stabilize the crystal structure.
