Lone‐Pair Interfaces That Divide Inorganic Materials into Ionic and Covalent Parts

Synthesis and crystal structure of Fe6Ca2(SeO3)9Cl4 – a porous oxohalide

“…The combination of stereochemically active lonepair cations and halide ions that often are terminating in the crystal structure act both as "chemical scissors" to open up the structures and to increase the possibilities for low-dimensional arrangements of transition metals. 4,5 A number of compounds with unusual crystal structures have been synthesized by utilizing this synthesis concept. This kind of compound may show interesting physical properties such as magnetic frustration because of the increased possibility for metals to adopt low-dimensional arrangements in the crystal structure 6,7 or nonlinear optical second harmonic generation (SHG) because of the increased possibility to form noncentrosymmetric crystal structures due to the one-sided coordination of the lone-pair cations.…”

“…The hard Fe 3+ ion tends to bond to only oxygen in oxohalides 7,12,13 while the weaker Lewis acids Cu 2+ and Ni 2+ tend to bond to both oxygen and halide ions and Cu + tends to bond only to halide ions. 5,6,14 There are also two crystallographically different Fe 3+ positions in 1. Fe(1) is bonded to six O atoms at distances in the range 1.969(7) Å to 2.032(3) Å forming a slightly distorted [Fe(1)O 6 ] octahedron.…”

Copper–lead selenite bromides: a new large family of compounds partly having Cu2+ substructures derivable from kagome nets

“…There is a known tendency for transition metal oxyhalide compounds containing 'lone pair' cations to crystallize in lowdimensional structural architectures due to the 'chemical scissors' (Mayerová et al, 2006;Jo et al, 2010) role of the stereochemically active lone electron pairs. All the structures described herein demonstrate the association of 'lone pairs' on Pb 2+ and Se 4+ in so-called lone electron pair micelles (Makovicky, 1997), thus demonstrating the presence of attractive interactions.…”

Cd2SeCl2O9: Synthesis and Characterization of Novel Selinite-Chlorate Material

“…Although a number of metal-halogen compounds in combination with chalcogens (Se 4+ , Te 4+ ) having unshared electron pairs have been synthesized in the literature [1][2][3][4][5][6][7] 8 are the only composites found with cadmium as metal. Such compounds have possible applications as future magnetic materials.…”