Bis(1,3-dimethyl-1H-imidazolium) hexa-fluoro-silicate: the second monoclinic polymorph.

The title compound, 2C5H9N2 (+)·SiF6 (2-), (I), crystallized as a new polymorph, different from the previously reported one (Ia) [Light et al. (2007 ▶) private communication (refcode: NIQFAV). CCDC, Cambridge, England].

Bis(1,3-dimethyl-1H-imidazolium) hexa-fluoro-silicate methanol 0.33-solvate.

The title compound, 6C5H9N2 (+)·3SiF6 (2-)·CH3OH, (I), was prepared by recrystallization of the crude salt from methanol along with solvent-free 2C5H9N2 (+)·SiF6 (2-) (II). Crystals of these solvatomorphs can be separated manually. The solvate (I) crystallizes in a rare hexa-gonal space group P6/mcc.

Trichlorido(1,3-dimethyl-2,3-di-hydro-1H-imidazol-2-yl-idene-κC (2))aluminium(III).

The title compound, [Al(C5H8N2)Cl3], was prepared by a thermolytic decomposition under high-vacuum conditions and presents a formal adduct of an Arduengo carbene, 1,3-dimethyl-1H-imidazol-2-yl-idene, and aluminium trichloride. The Al atom adopts a pseudo-tetra-hedral CCl3 coordination environment. All N and C atoms, the Al atom, one of the Cl atoms, and all aromatic H atoms of the mol-ecule lie on a mirror plane.

2-{(E)-N-[2-(1H-Inden-3-yl)eth-yl]imino-meth-yl}-1H-imidazole.

The asymmetric unit of the title compound, C(15)H(15)N(3), contains two crystallographically independent mol-ecules with very similar geometries. The imidazole and indenyl planes are approximately orthogonal, making dihedral angles of 88.21 (9) and 83.