The complex (CO), Co-Rh (CO)(PEt,),(I) was prepared by the reaction of Na [Co (CO),] with truns-RhCI (CO)(PEt,), and has been structurally characterized: P2,/c, a= 8.294 (1) A, b= 17.746 (6) A, c= 16.575 (3) A, 0= 104.37 (1) O, V= 2363.2 (8) A', Z= 4, R,= 0.042 and R2= 0.053 for 3209 reflections with F> 60 (F). The Co center is ligated by four carbonyls in an approximately tetrahedral arrangement while the Rh center has a square-planar ...