Octachalcogen Cations Te₈ ²⁺, Se₈ ²⁺, and Mixed (Te_8-xSe_x)₈ ²⁺ Stabilized by Chlorometallates of Bi, Zr, and Hf: Synthesis and Crystal Structures of Se₈[Bi₄Cl₁₄] and E₈[MCl₆] (E = Se, Te; M = Zr, Hf)

Abstract

Octaselenium(2+), Octatellurium(2+), Chalcogen Polycations, Halogenobismutates(III), Crystal StructureThe title compounds were obtained by the reaction of elemental chalcogens E (E = Se, Te) with the respective tetrachlorides ECU and the Lewis acidic metal halides ZrCL, HfCU, and BiCfi. An alternative way, particularly for the preparation of mixed Se/Te-species, is the enlargement of smaller cationic rings in E4MC16] (M = Zr, Hf) by adding the respec tive complementary chalcogen. All reactions were carried out in sealed, evacuated glass am poules at temperatures between 120 °C and 220 °C, and yielded black crystals of SegfBijClu], (Te5.oSe3.o)[HfCl6], (Te5.3Se2.7 )[ZrCl6], (Teft.sSei.sMZrCU] and Te8[HfCl6], which have been identified by crystal structure analyses. All five compounds contain eight-membered chalcogen rings in an endo-exo-conformation which are isostructural to the known octachalcogen dica tions E82+ (E = S, Se, Te). While in (Te5.0Se3.o)[HfCl6], (Te5.3Se2.7 )[ZrCl6], (Te6.5Se,.5)[ZrCl6 _] and TesfHfClft] the molecular polycations are surrounded by discrete, octahedral [MClö]"-counterions, Se4 [Bi4CZT14] contains a two-dimensional polymeric anion ([Bi-jCl^ ] 2)" built of a variety of vertex and edge-sharing BiClv-polyhedra (x = 6 , 7). The Bi-Cl bond lengths are spread over a wide range between 250 and 350 pm.

Solvothermal Synthesis and Crystal Structure of Te8[U2Br10], Containing a Polymeric Chalcogen Cation (Te82+)n

“…3). [12] with the shape of a ring and a six center-two electron bond across the ring [2]. In Te 8 [WCl 6 ] 2 [13] a Te 8 2ϩ ion with a bicyclic structure of two condensed five-membered rings is present.…”

A One-Dimensional Polymeric Form of the Polycation Te8 2+ in the Structure of Te8[Bi4Cl14]

“…The eightatomic ions in Teg [ReClö] [ 14], Teg [MC16] (M = Zr, Hf) [7], S8[AsF6]2 [15], and S8 [A1C14]2 [16] are all isomorphous. These ions are discrete, ring shaped clusters with a six center-two electron bond across the ring [5].…”

“…Here a small increase of Bi-Cl distances is present, starting with two short bonds Bi( 1 )-Cl ( 1) and Bi(l)-Cl(3) of averaged 249 pm. Since two of the Cl atoms (Cl(13), Cl (14)) do not exhibit BiCl bonds shorter than 283 pm, the structure of the chlorobismutate [Bi4Cli42 -]" can be interpreted as an aggregate of B iC^ molecules and C l-ions with the formula [(BiCl3>4 (Cl_ )2]n-It is remarkable that now three compounds built of chalcogen polyca tionic clusters and a chlorobismutate of the for mula Bi4C li42~ are known, namely Se4[Bi4C li4] [6], Se8[Bi4Cli4] [7], and Te8[Bi4Cli4]. The com mon structural feature of all three anions is the link ing of irregular Bi-Cl polyhedra with coordination number 7 and 8 to two-dimensional arrangements.…”

Selen-Polykationen stabilisiert durch polymere Chlorobismutat-Anionen: Synthesen und Kristallstrukturen von Se4[Bi4Cl14] und Se10[Bi5Cl17]

“…325,0 pm kann man sie als anna Èhernd isolierte Chloridionen auffassen, wobei Cl(4) in Form eines gestauchten Tetraeders und Cl(5) quadratisch-planar von Bi umgeben ist. Nimmt man Cl(4) und Cl (5) Cl 14 ] formelgleiches Chlorobismutat-Anion entha È lt [11]. Beiden Strukturen ist die zweidimensional-polymere Ausdehnung der komplexen Anionen gemeinsam, auch a Èhneln sie sich in der schichtartigen Abfolge von Kationen und Anionen.…”

“…The different BiCl x polyhedra are linked by sharing common vertices, edges, and faces. Cl 14 ] fu È hrte, die Synthese eines Selenpolykations mit einem Halogenobismutat als Anion [11]. Durch Variationen der Reaktionsfu È hrung entdeckten wir in diesem Dreistoffsystem noch zwei weitere Phasen, woru È ber im folgenden berichtet wird.…”