Tetra­amminelithium triamminelithium tris­ulfide, [Li(NH₃)₄][Li(NH₃)₃S₃]

The title compound, [Li(NH₃)₄]⁺[Li(NH₃)₃S₃]⁻, an ammo­niate of the previously unknown lithium tris­ulfide, was obtained from the reaction of lithium and sulfur in liquid ammonia. The asymmetric unit consists of two crystallographically independent formula units. The [Li(NH₃)₄]⁺ cations are close to regular LiN₄ tetra­hedra. The anions contain LiSN₃ tetra­hedra; the S—S—S bond angles are 110.43 (5) and 109.53 (5)°. In the crystal, the components are linked by multiple N—H...S hydrogen bonds. A weak N—H...N hydrogen bond is also present.

Acetyl­ene–ammonia–18-crown-6 (1/2/1)

The title compound, C₂H₂·C₁₂H₂₄O₆·2NH₃, was formed by co-crystallization of 18-crown-6 and acetyl­ene in liquid ammonia. The 18-crown-6 mol­ecule has threefold rotoinversion symmetry. The acteylene mol­ecule lies on the threefold axis and the whole mol­ecule is generated by an inversion center. The two ammonia mol­ecules are also located on the threefold axis and are related by inversion symmetry. In the crystal, the ammonia mol­ecules are located below and above the crown ether plane and are connected by inter­molecular N—H...O hydrogen bonds. The acetyl­ene mol­ecules are additionally linked by weak C—H...N inter­actions into chains that propagate in the direction of the crystallographic c axis. The 18-crown-6 mol­ecule [occupancy ratio 0.830 (4):0.170 (4)] is disordered and was refined using a split model.