THE VIBRATIONS OF BRIDGING CARBONYL GROUPS AS MORE SENSITIVE INDICATORS OF MOLECULAR-GEOMETRY THAN TERMINAL CARBONYL GROUPS IN TRANSITION-METAL CARBONYL CLUSTER COMPOUNDS .2. SOME M(5) SPECIES

A study of the v(CO) spectra of six M(5) trigonal bipyramidal cluster carbonyls shows that the patterns observed are consistent with the pos tulate that the bridging region spectra are more structure-sensitive t han are the terminal ones. A qualitative suggestion is made concerning predictions for species with bridge CO groups with significantly diff erent v(CO) zeroth-order frequency differences.