Octa-kis[2,2',5,5'-tetra-thia-fulvalenium(0.5+)] bis-[hexa-molybdate(2-)] acetonitrile solvate.

The asymmetric unit of the title compound, (C(6)H(4)S(4))(8)[Mo(6)O(19)](2)·CH(3)CN, contains two halves of two centrosymmetric [Mo(6)O(19)](2-) hexa-molybdate anions, which are each built up from six distorted MoO(6) octa-hedra sharing common edges and one common vertex at the central O atom, six tetra-thia-fulvalene cations (three of which are located on mirror planes) to balance the charge and a half of an acetonitrile solvent mol-ecule, likewise located on a mirror plane. The two central hexa-molybdate O atoms occupy special positions 2a and 2d, respectively. The cations and anions are inter-linked through C-H⋯O contacts.

Ammonium tris-(tetra-ethyl-ammonium) hexa-cosa-oxidoocta-molybdate.

The structure of the title compound, NH(4)(C(8)H(20)N)(3)[Mo(8)O(26)], is built up by discrete cations and anions, with two formula units in the asymmetric unit. The β-octa-molybdate anions are linked to the ammonium cations via N-H⋯O hydrogen bonding involving terminal oxide groups and to the tetra-ethyl-ammonium cations via weak C-H⋯O inter-actions.