[NEt(4)](2)[enH](2)[Ge2Se6] and [NEt(4)](4)[Sn4Se10] have been synthesized electrochemically by the reduction of metal chalcogen alloys in an electrolyte solution of NEt(4)Br in ethylenediamine. The structures of both compounds have been determined by single-crystal X-ray methods. [NEt(4)](2)[enH](2)[Ce2Se6] crystallizes in the triclinic space group C-i(1)- with one formula unit in a cell of dimensions a = 7.805(4) Angstrom, b = 10.747(6) Angstrom, c = 11.445(6) Angstrom, alpha = 110.33(2)degrees, beta = 97.19(3)degrees, gamma = 92.62(2)degrees, and V = 889.0(8) Angstrom(3) (T = 115 K). Final agreement indices for [NEt(4)](2)[enH](2)[Ge2Se6] are 0.116 for R(w)(F-o(2)) for all the 2982 data and 0.055 for R(1) for the 1958 reflections with F-o(2) greater than or equal to 2 sigma(F-o(2)) (158 variables). [NEt(4)](4)[Sn4Se10] crystallizes in the cubic space group T-d(4)- with eight formula units in a cell of dimensions a = 22.170(7) and V = 10897(6) Angstrom(3) (T = 115 K). Final agreement indices for [NEt(4)](4)[Sn4Se10] are 0.123 for R(w)(F-o(2)) for all the 1490 data and 0.057 for R(1) for the 1138 data with F-o(2) greater than or equal to 2 sigma(F-o(2)) (90 variables). The [Ge2Se6](4-) anion is composed of a pair of edge-sharing tetrahedra. Each of the two independent [Sn4Se10](4-) anions has the adamantane-type structure consisting of four Sn tetrahedra, each of which shares three edges with three similar tetrahedra; the symmetry of one anion is (4) over bar (S-4) while that of the other is 23 (T). Although both the [Ge2Se6](4-) and [Sn4Se10](4-) anions are new, each has group 14 structural analogues.