Hexa­aqua­nickel(II) di­hydrogen hypodiphosphate

The asymmetric unit of the title compound, [Ni(H₂O)₆](H₂P₂O₆), contains one-half of the hexa­aqua­nickel(II) cation and one-half of the di­hydrogen hypodiphosphate anion. In the complex cation, the Ni²⁺ atom is located on an inversion center and has an octa­hedral coordination sphere. The P—P distance in the centrosymmetric anion is 2.1853 (7) Å. In the crystal, discrete [Ni(H₂O)₆]²⁺ cations and (H₂P₂O₆)²⁻ anions are stacked in columns parallel to the c axis and are linked into a three-dimensional network by medium-strength O—H...O hydrogen bonds.

μ-Hexa­thio­metadiphosphato-bis­[(1,4,7,10,13,16-hexa­oxa­cyclo­octa­decane-κ⁶O)rubidium] aceto­nitrile disolvate

The asymmetric unit of the title compound, [Rb₂(P₂S₆)(C₁₂H₂₄O₆)₂]·2CH₃CN, contains one half of an [Rb(18-crown-6)₂]₂[P₂S₆] unit and one aceto­nitrile solvent mol­ecule. The [Rb(18-crown-6)]₂[P₂S₆] unit is completed by inversion symmetry. Its Rb⁺ ion is situated near the centre of the macrocyclic cavity, but is displaced by 0.8972 (1) Å from the O atoms of the crown in the direction of the [P₂S₆]²⁻ moiety. The overall coordination number of the cation is eight, defined by the six crown ether O atoms and by two terminal S atoms of the [P₂S₆]²⁻ anion. The hexa­thio­metadiphosphate anion is built up from two tetra­hedral PS₄ units joined together by a common edge. The crystal structure is characterized by alternating layers of [Rb(18-crown-6)]₂[P₂S₆] and aceto­nitrile solvent mol­ecules stacked along [010].

Ethane-1,2-diaminium 2,2′-[tereph­thal­oyl­bis(aza­nedi­yl)]di­acetate tetrahydrate

In the title salt hydrate, C₂H₁₀N₂²⁺·C₁₂H₁₀N₂O₆²⁻·4H₂O, each of the ions is located about a centre of inversion and the asymmetric unit is completed by two water molecules in general positons. In the crystal, the cations, anions and water mol­ecules are connected by O—H...O and N—H...O hydrogen bonding into a three-dimensional network.