Mixed-anion dihalides

Halides, 7 1-26 actinide elements, 2 195-233 anion dependence, 39 139 berkelium, 28 48, 51-53 beryllium, 14 255-332 binary, 35 237-246, 274-280 decomposition, 35 277 dichalcogen dihalides, 35 279-280 equilibrium studies, 35 242 mixed-ligand halides, 35 244-246 reactions, 35 246 selenium halides, 35 240-241... 

A mechanism that accounts for the oxidative addition of halocarbons has been proposed for the two d8-d8 dimers (Figure 4) (23). The mechanism involves the oxidative quenching of the triplet excited state of the metal dimer as the primary photoprocess. This gives a radical anion species that dissociates a halide, thereby producing an organic radical. The dissociated halide adds to the partially oxidized metal dimer to form a mixed valence Ir -Ir -X or Pt 1-Pt -X intermediate. This intermediate reacts further with the remaining organic radical (presumably in a second, thermal electron transfer step) to form the final d2-d2 dihalide dimer. 

Based on the similar crystal structure one might expect extended solid solutions between Cdl2-type dihalides and Bila-type trihalides, as well as between CdCl2-type and AlCla-type halides. This, however, appears not to be the case. The systems MgCl2—CrCla, FeCl2—CrCla and MnCl2—CrCla were found to be similar to eutectic-type systems [906]. Moreover, the different anion stacking is sufficient to prevent mixed-crystal formation between CrCla and FeCla [906]. 

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