Cs₂B₂S₄ – Ein Salz der dimeren Metathioborsäure

Abstract

Cs2B2S4 (I41/acd; a = 7,270(1) Å, c = 35,737(7) Å; Z = 8; Subzelle: I4/mmm; a′ = 5,141(1) Å, c′ = 17,868(4) Å, Z = 2) wird durch Reaktion von Caesiumsulfid Cs2S mit amorphem Bor und elementarem Schwefel im Verhältnis 1:2:3 bei einer Reaktionstemperatur von 600°C mit anschließendem Tempern dargestellt. Die Kristallstruktur besteht aus molekularen, planaren [B2S4]2−‐Einheiten mit extrem gespannten [B2S2]‐Vierringen, zwischen denen sich die neunfach koordinierten Alkalimetallkationen befinden. Das Strukturmotiv zweier kantenverknüpfter BS3‐Gruppen wird hier erstmals in der Chemie der Thioborate isoliert beobachtet, ist jedoch als Baustein des polymeren Bor‐Schwefel‐Gerüsts im B2S3 bekannt.

Syntheses and Crystal Structures of the Novel Ternary Thioborates Na3BS3, K3BS3, and Rb3BS3

“…The ability of boron to form trigonal planar as well as tetrahedral chalcogen coordinations results in several interesting structural features in these thio-and selenoborates. Four different types of these isolated chalcogenoborate anions are currently known, i. e. the highly charged anions [BQ 3 ] 3± (Q = S, Se) [6±9], [B 2 S 4 ] 2± [10], [B 2 S 5 ] 2± [11], and [B 3 S 6 ] 3± [8, 12±14]. Four different types of these isolated chalcogenoborate anions are currently known, i. e. the highly charged anions [BQ 3 ] 3± (Q = S, Se) [6±9], [B 2 S 4 ] 2± [10], [B 2 S 5 ] 2± [11], and [B 3 S 6 ] 3± [8, 12±14].…”

BaB2S4: An Efficient and Air-Stable Thioborate as Infrared Nonlinear Optical Material with High Laser Damage Threshold

“…The coordination numbers of the B atoms in thioborates can be either three (the [BS 3 ] 3– groups) or four (the [BS 4 ] 5– tetrahedra) forming 0D-cluster, 1D-chain, 2D-layer, and 3D-network. − Additionally, similar bond length between S–S (1.890 Å) and B–S (2.078 Å) in perthioborates can make the connection modes of the B–S units additional various structure types with unusual S–S bonds, including [B 2 S 5 ] 2– cluster, [BS 3 ] − chain, [B 3 S 10 ] 3– chain, and [B 2 S 7 ] 2– chain . Trigonal-planar [BS 3 ] 3– units can tend to form isolated clusters, including [BS 3 ] 3– , [B 2 S 4 ] 2– , [B 2 S 5 ] 2– , [B 3 S 6 ] 3– , etc., and tetrahedral [BS 4 ] 5– units are always connected to form T n -supertetrahedra cluster, , such as [B 4 S 10 ] 8– (T 2 ) and [B 10 S 20 ] 10– (T 3 ) . However, the isolated [BS 4 ] 5– has not been observed so far.…”

Na2[B18Se16]: The First 3D Polymeric Selenoborato‐closo‐dodecaborate

“…Binary boron sulfides and selenides [1, 3Ϫ5] as well as ternary and quaternary thio-and selenoborates contain boron atoms in a trigonal-planar coordination, for which various novel types of chalcogenoborate anions have been observed. Typical examples are the small, highly charged anion entities [BS 3 ] 3Ϫ [6Ϫ8], [BSe 3 ] 3Ϫ [9], [B 2 S 4 ] 2Ϫ [10], [B 2 S 5 ] 2Ϫ [11], and [B 3 S 6 ] 3Ϫ [8, 12Ϫ14], which are characteristic structural features in non-oxide chalcogenoborates of alkali and alkaline earth metals. In contrast to a tetrahedral chalcogen coordination which is found not only in thio-but also extensively in selenoborates [15Ϫ22], examples for boron atoms in a trigonal-planar coordination with selenium atoms are scarce.…”