Lead indium bismuth chalcogenides. II. Structure of Pb4In3Bi7S18

Abstract

symmetry space group Pbna (alternative setting for Pbcn) with a twofold rotation axis at x,0,¼. Inspection of the packing diagram in Fig. 2 shows that this is indeed the case and all atom positions in picrate ion (1) are closely approximated to atom positions of ion (2) ~z).by the pseudo-operator (x, -y,The position and orientation of the dimethylammonium ions break the pseudosymmetry. N(3) and N(4) of the dimethylammonium ions are well defined (Ueq 0.04 A 2) and lie 0.2 and 0.8 A respectively off the pseudo twofold axis.The structure is clearly laminar with sheets of anions hydrogen-bonded to sheets of cations. Picrate ions are only related to each other by symmetry within the sheets; adjacent sheets are only related by the pseudo twofold axis. The strongest interactions are hydrogen bonds between the deprotonated O on the picrate ions and the ammonium H atoms. Each O acts as a hydrogen-bond acceptor for two H atoms providing four crystallographically unrelated hydrogen bonds as given in Table 3 All other non-bonded contacts (Table 3) are within expected ranges for van der Waals interactions, though the short contacts involving the picrate aromatic H atoms to O(n21) and O(n61) ranging between 2.4 and 2-7 A suggest a genuine electrostatic interaction. WALKINSHAW SHORT-FORMAT PAPERS

Synthesis and Phase Width of Quaternary Selenides Pb4InxM6−xSe13 (M = Bi, x = 2.1−2.8; Sb, x = 2)

“…We have investigated the effect of indium or transition metals on the structures and properties of quaternary chalcogenides containing heavy main-group elements Sb, Bi, Sn, and Pb . Before this work the reported phases were quaternary sulfides Pb 1.6 In 8 Bi 4 S 19 , Pb 4 In 3 Bi 7 S 18 , and Pb 4 In 2 Bi 4 S 13 . No quaternary phase has been reported in the In−Pb−M−Se (M = Sb, Bi) system.…”

“…24 Before this work the reported phases were quaternary sulfides Pb 1. 6 In 8 Bi 4 S 19 , 25 Pb 4 In 3 Bi 7 S 18 , 26 and Pb 4 In 2 Bi 4 S 13 . 27 No quaternary phase has been reported in the In-Pb-M-Se (M=Sb, Bi) system.…”

Novel Quaternary Lanthanum Bismuth Sulfides Pb2LaxBi8-xS14, Sr2LaxBi8-xS14, and Cs2LaxBi10-xS16 with Complex Structures

“…The M(5)/La(5) site is seven-coordinate with monocapped trigonal coordination and distances varying between 2.795(5) and 3.029(5) Å, while site M(6)/La(6) is eight-coordinate having a bicapped trigonal prismatic coordination with distances varying between 2.875(3) and 3.248(5) Å. This fragment is also observed in ALn 1 ± x Bi 4 ± x S 8 23 (A = K, Rb; Ln = La, Ce, Pr, Nd), Gd 2 S 3 , CeTmS 3 , La 10 Er 9 S 27 , PbBi 2 S 4 ,17a Pb 4 In 3 Bi 7 S 18 , and La 4 Bi 2 S 9 . One characteristic of this fragment is that the monocapped prisms form an infinite column by sharing edges while the bicapped prisms stack by sharing trigonal faces.…”