catena-Poly[4-methylmorpholin-4-ium [[dichloridobismuth(III)]-di-μ-chlorido]]

The asymmetric unit of the title complex, {(C5H12NO)[BiCl4]}n, contains two bridging and two cis non-bridging chloride ligands coordinated to a central BiIII atom, and one 4-methylmorpholin-4-ium cation. The BiIII atoms are linked by the bridging chloride ligands into linear chains parallel to the c axis. The chloride ions create a pseudo-octahedral geometry about each BiIII atom. Bifurcated N—H⋯Cl hydrogen bonds link the cations to the anionic chains.

The asymmetric unit of the title complex, {(C 5 H 12 NO)- [BiCl 4 ]} n , contains two bridging and two cis non-bridging chloride ligands coordinated to a central Bi III atom, and one 4methylmorpholin-4-ium cation. The Bi III atoms are linked by the bridging chloride ligands into linear chains parallel to the c axis. The chloride ions create a pseudo-octahedral geometry about each Bi III atom. Bifurcated N-HÁ Á ÁCl hydrogen bonds link the cations to the anionic chains.

Related literature
For the structures of related amino compounds, see: Turnbull (2007). For the ferroelectric properties of related amino derivatives, see: Fu et al. (2011a,b,c).

Comment
Simple organic salts containing amino cations have attracted attention as materials that display ferroelectric-paraelectric phase transitions (Fu et al., 2011a,b,c). In this study, we describe the crystal structure of the title compound, N-methylmor- The asymmetric unit contains four independent Cl atoms, one Bi III atom and one organic cation (Fig. 1). All bond lengths and angles are normal and comparable with those reported for the cation in a related Ni(III) compound (Turnbull, 2007).
The non-bridging (Cl1 & Cl2) and bridging Cl (Cl3 & Cl4) atoms create a pseudo-octahedral geometry about each Bi (III) atom. The Bi III atoms are linked via bridging Cl ions into linear chains that propagate parallel to the c axis.
In the crystal structure, the amino N1 atom is involved in hydrogen bonds with the Cl atoms (Cl2 and Cl3) with the N-H···Cl distance of 3.434 (6) and 3.410 (6) Å, respectively. The bifurcated N-H···Cl H-bonds link the cations to the inorganic anion chain. (Fig. 2, Table 1).

Refinement
All H atoms attached to C atoms were fixed geometrically and treated as riding with C-H = 0.97 Å (methylene) and C-H = 0.96 Å (methyl) with U iso (H) = 1.2U eq (methylene) and U iso (H) = 1.5U eq (methyl). Positional parameters of the N-bound H atom were intially refined freely, but subsequently restrained using a distance of 0.90 Å and, in the final refinements treated as riding on their parent nitrogen atoms with U iso (H)=1.2U eq (N).

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2sigma(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.