Frozen inert gas matrices of N2 and Ar containing 02 and In or Ga atoms have been prepared by matrix isolation techniques and studied by infrared absorption spectroscopy. Analyses of the spectra have shown that these reagents react to produce metal superoxide molecules, M+02", which are similar to those of the alkali and alkaline earth metals. The stretching modes of these species absorb in the regions of 1080-1090 cm"1 for r1(A1), 330-380 cm"1 for * 2( ), and 270-290 cm"1 for ^(Bj). In addition to the superoxides, various aggregate species are produced. One of these has been identified as the superoxide dimer, which apparently has an 02M-M02 structure of I)2d symmetry. Another aggregate has been identified as a rhombic M02M species which is formed by the addition of a metal atom to the superoxide. Small quantities of the suboxide dimer (ln20)2 also were detected in these matrices. The evidence indicates that this species was formed by the addition of an In atom to each oxygen of the In02In(D2ft) species. This dimer is of interest because it is readily formed by aggregation of the suboxide monomer in experiments involving the vaporization of the condensed oxide systems.

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6QB The yields of and have been measured in at ambient temperature as a function of e aq~, e aq~]~O D e aq~] D~]~OD D 2 O scavenger concentration. At scavenging powers O107 s~1 is 10% larger than its value in but for scavenging powers G(e aq~) H 2 O, P3 ] 108 s~1 the yields of and are the same in both solvents, indicating that scavenging in e aq~, e aq~]~O D e aq~] D~]~OD the spurs suppresses the reactions leading to the di †erent primary yields. The absorption spectrum of is found to be verỹOD similar to that of comprising a weak band rising into the UV between 320 and 220 nm with m2 mol~1 atOH, e 250 \ 50^2 20 ¡C. The shape of the band is the same at 200 ¡C. Rate constants for the reactions and have beeñOD ]~OD D~]~OD measured up to 200 ¡C, on the assumption that for is independent of temperature. As with the corresponding reactions e 250~O D in they show non-linear Arrhenius behaviour, being close to the di †usion-controlled value at ambient temperature, but an H 2 O, order of magnitude less than this value at 200 ¡C. The values of the rate constants are very similar in both solvents.

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