Reactions of nine-atom deltahedral clusters (Zintl ions) of germanium, Ge-9(n-) (n = 2, 3, 4), with alkyl chlorides, RCl (R = Bu-t, Bu-n, Bu-s, Am-t), yielded the corresponding dialkylated dimers of Ge-9 clusters [R-Ge-9-Ge-9-R](4-). The Bu-t derivative with [K(2,2,2-crypt)](+) countercations was characterized in the solid state by single-crystal X-ray diffraction as [K(2,2,2-crypt)](4)[Bu-t-Ge-9-Ge-9-Bu-t]center dot 7en (monoclinic, C2/c, a = 35.0914(10) angstrom, b = 24.8161(6) angstrom, and c = 16.8782(5) angstrom, beta = 94.0136(17)degrees, V = 14662.0(7) angstrom(3), and Z = 4) and in solution by H-1 and C-13 NMR. All species were also characterized in solution by electrospray mass spectrometry in the negative-ion mode. These are the first main group deltahedral clusters functionalized with purely organic substituents.