New solvent-separated ion-pair compounds and extended structures containing ytterbium(II)-transition metal isocarbonyl linkages were synthesized. [Yb(THF)(6)][M(CO)(5)](2) (1, M = Mn; 2, M = Re) were prepared via transmetalation reactions between Yb metal and Hg[M(CO)(5)](2) in THF. Reflux of 1 in Et2O afforded {Yb(THF)(2)( Et2O)(2)[(mu-CO)(2)Mn(CO)(3)](2)}(infinity) (3) which is a sheet-layer structure. In ether solution, 3 is converted to {Yb(THF)(4)[( mu-CO)(2)Mn(CO)(3)](2)}(infinity) (4) which has a linear structure. In both 3 and 4, ytterbium is 8-coordinated (distorted square antiprism geometry), four coordination sites occupied by molecules of solvent and four more by oxygen atoms of isocarbonyl linkages. The [Mn(CO)(5)](-) anion has trigonal bipyramidal geometry and is linked to ytterbium through two equatorial carbonyls. The formation of two minor products, (THF)(2)Mn-3(CO)(10) (5) and [(THF)(5)Yb(mu-CO)Mn-3( CO)(13)][Mn-3(CO)(14)] (6), was observed during condensation of 1 into 3 and 4.