The so-called "platinum carbonyl", which probably consists of [Pt 3n (CO) 6n ] 2À oligomers with an average n value of approximately 10, was reported several years ago. [1,2] To date only discrete [Pt 3n (CO) 6n ] 2À oligomers with n = 1-5 have been selectively synthesized and characterized. [2][3][4][5][6][7] 1D molecular metal wires, [8,9] and 1D and 2D superclusters [10,11] are interesting in themselves as low-dimensional molecular materials with possible applications in molecular electronics and nanolithography. [12][13][14] The recent improvement of the synthesis of "platinum carbonyl" [7] prompted a reinvestigation of the chemistry of the [Pt 3n (CO) (CO) 48 ] reveals a distribution of oligomers centered at n = 5, with peaks of lesser intensity at n = 4 and n = 6. The observed distribution is narrower than the bellshaped distribution of n = 3-10 oligomers, centered at n = 6 or 7, exhibited by "platinum carbonyl".[7] The absence of the expected molecular peak for the [Pt 24 (CO) 48 ] 2À ion and the observed distribution of oligomers with n = 4-6 is clearly due to fragmentation processes occurring during the ESI-MS analysis, because the IR spectrum of the injected solution does not show the characteristic carbonyl absorptions of oligomers with n = 4-6.[2]The nature of the [NBu 4 2À oligomer consists of a sequence of eight {Pt 3 (CO) 6 } units stacked with a clock-or anticlockwise twist of 3-268 between consecutive units. The twist probably allows the minimization of repulsive intra-and intermolecular nonbonding interactions between the carbonyl groups of consecutive units and of adjacent oligomers. This twist is also responsible for the Pt À Pt contacts between neighboring {Pt 3 (CO) 6 } units being longer than the distance between the Pt 3 planes of these units. The PtÀPt bond distances within the individual {Pt 3 (CO) 6 } units fall in the narrow range of 2.666(2)-2.679(2) . In contrast, the PtÀPt contacts between neighboring {Pt 3 (CO) 6 } units are spread over a wider range of 3.024(2)-3.307(2) . The shortest interplane distances occur between the inner {Pt 3 (CO) 6 } units. The interplane distances become longer towards the top and bottom of the stack, like in an accordion (Figure 1). The longest PtÀPt contacts between neighboring {Pt 3 (CO) 6 } units (3.292(2)-3.307(2) ) are those involving the top {Pt 3 (CO) 6 } unit, and these are deliberately not shown as bonds in Figure 1. The PtÀPt contacts and the interplane distances (3.21 ) between this unit and the {Pt 21 (CO) 42 } stacks above and below it are the same. Thus, the pseudo-1D [Pt 24 (CO) 48 ] 2À molecular ions are arranged in infinite chains composed of alternating