TePEt(3) reacts-quantitatively with [M(Se-4)(2)](2-) anions (M = Zn, Cd, Hg) in DMF. The ring-bound Se atoms are substituted by Te atoms in the MSe(4) rings before the metal-bound Se atoms are. For n less than or equal to 4, the reaction of n equiv of TePEt(3) with 1 equiv of [M(Se-4)(2)](2-) thus affords mixtures of [MTe(n)Se(8-n)](2-) anions, in which the Se atoms remain metal-bound. The pure isomer [PPh(4)](2)[Hg(Te2Se2)(2)] crystallizes in the tetragonal space group S-4(2)-I (4) over bar with four formula units in a unit cell of dimensions n = 21.174(5) Angstrom, c = 10.976(3) Angstrom, and V = 4921(2) Angstrom(3) (T = 108 K). The values of the agreement indices R(F) and R(W)(F-2) are 0.051 and 0.102, respectively. The [PPh(4)](+) salts of [Hg(Se-4)(2)](2-) and [Hg(TeSe3)(Se-4)](2-) cocrystallize in a 0.42:0.58 ratio in the monoclinic space group C-2h(5)-P2(1)/n with eight formula units in a unit cell of dimensions a = 22.911(3) Angstrom, b = 20.161(4) Angstrom, c 23.685(2) Angstrom, beta = 118.65(1)degrees, and V = 9601(2) Angstrom(3) (T 108 K). The values of the final agreement indices are 0.078 and 0.153. The [PPh(4)](+) salts of [Hg(Se-4)(2)](2-), [Hg(TeSe3)(Se-4)](2-), [Hg(TeSe3)(2)](2-), and [Hg(Te2Se2)(Se-4)](2-) cocrystallize in a 0.05:0.39:0.43:0.13 ratio in the monoclinic space group C-2h(5)-P2(1)/c with eight formula units in a unit cell of dimensions a = 22.940(3) Angstrom, b = 20.220(2) Angstrom, c = 23.797(2) A, beta = 118.50(1)degrees, and V = 9701(2) Angstrom(3) (T = 108 K). The values of the agreement indices are 0.059 and 0.127. From the Se-77 and Te-125 NMR chemical shifts, which are sufficiently sensitive, it was possible with one exception to distinguish every unique chalcogen atom in every [MTe(n)Se(8-n)](2-) anion from every other one; these resonances are assigned and discussed.