. Author manuscript; available in PMC: 2006 Mar 14.

Published in final edited form as: J Am Soc Mass Spectrom. 2001 Mar;12(3):250–257. doi: 10.1016/S1044-0305(00)00224-5

Table 1.

Reaction rate constants (and reaction efficiencies) for solvent exchange between alkaline earth metal ions and benzene. Rate constants are reported in × 10⁻¹⁰ cm³/molecule·s.^a Reaction efficiencies are reported in percentages (%) and were obtained using the calculated Langevin collision rate constants [27]

Metal	Hepta-	Hexa-	Penta-	Tetra-
Mg²⁺	0.5 ± 0.2 (5)	0.02 ± 0.01 (0.2)	0.04 ± 0.01 (0.4)	4.4 ± 0.2 (38)
Ca²⁺	0.4 ± 0.2 (4)	0.5 ± 0.2 (5)	3.3 ± 0.1 (31)	2.9 ± 0.1 (26)
Sr²⁺	1.8 ± 0.3 (18)	2.1 ± 0.1 (21)	2.8 ± 0.1 (28)	2.5 ± 0.1 (24)
Ba²⁺	3.8 ± 0.3 (39)	2.7 ± 0.1 (28)	3.2 ± 0.2 (32)	3.3 ± 0.1 (33)

The reported errors correspond to the standard deviation of the rate constants determined from the kinetic data and do not include uncertainties in the measured pressure of benzene.