
TY  - JOUR
A1  - Baldwin, WG 
A1  - Stranks, DR 
T1  - Rates of substitution of the hydrated beryllium cation by hydrogen fluoride and fluoride ion
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1968
VL  - 21
IS  - 9
SP  - 2161
EP  - 2173
KW  - 
UR  - https://doi.org/10.1071/CH9682161 
N2  - The rate of formation of the monofluoroberyllium species Be(OH2)3F+ was measured by a conductimetric stopped-flow technique. At acid concentrations exceeding 0.01M two parallel reaction paths were identified:     Be(OH2)42+ +F- &#8596; Be(OH2)3F+     (k1,k-1)    Be(OH2)42+ +HF- &#8596; Be(OH2)3F+H+(k2,k-2)    At 25º and an ionic strength of O.2M, k1 = 724 ± 95 l. mole-l sec-1 and k2 = 73 ± 3 l. mole-1 sec-1. Both substitution paths exhibit activation energies of 8.9 ± 0.8 kcal/mole. The data are interpreted in terms of an SN11P mechanism which is also proposed for the analogous Be2+ + SO42- reaction. Outer-sphere ion pairs of Be(OH2)42+ with respectively F-, HF, and SO42- undergo substitution with the same activation energy. A linear free energy relation exists between the rate of formation of the inner-sphere complexes from the outer-sphere ion pairs and the accompanying free energy changes. 
ER  -

