The carbyne compound [Mo(≡CC~6H~5)Br(CO)~2(PY)~2] 1 reacts with Co~2(CO)~8, Fe~2(CO)~9 or Mn~2(CO)~1~0 to give trimetal cluster compounds, but does not react with the compound [C~5H~5)~2Mo~2-(CO)~4] which containing Mo≡Mo triple bonds. The metal core of trimetal cluster compounds possesses tetrahedral structures.

Key words: SYNTHESIS, TETRAHEDRAL, INFRA-RED, MOLYBDENUM, CARBONYL COMPOUNDS, COBALT, ELEMENTAL ANALYSIS