Synthesis, Structure, and Electronic Properties of Sn₉O₅Cl₄(CN₂)₂

Abstract

The formation of the new compound Sn 9 O 5 Cl 4 (CN 2 ) 2 is reported and placed in the context of several other recently discovered tin carbodiimide compounds (Sn(CN 2 ), Sn 2 O(CN 2 ), and Sn 4 Cl 2 (CN 2 ) 3 ), all of which contain divalent tin. The crystal structure of Sn 9 O 5 Cl 4 (CN 2 ) 2 , as determined by X-ray powder diffraction, includes an unusual [Sn 8 O 3 ] cluster, in which tin atoms form the motif of a hexagonal bipyramid. An additional tin atom and two oxygen atoms connect these clusters into chains. Mossbauer spectroscopy shows tin to predominantly adopt the +2 oxidation state, and electronic structure calculations predict Sn 9 O 5 Cl 4 (CN 2 ) 2 to be a semiconductor.

Synthesis, Structure and Electronic Properties of Three Tin Oxide Halides

“…Recent studies of the tin oxide carbodiimide compounds Sn 2 O(CN 2 ) [20] and Sn 9 O 5 Cl 4 (CN 2 ) 2 [21] suggested the existence of some yet unknown tin oxide halides, which are reported in this work. Building upon band structures and photochemical properties previously reported for tin oxide carbodiimide compounds [20–22] we herein present the electronic band structure and electron localization function of Sn 7 O 4 Cl 6 , as calculated by density functional theory.…”

“…In the course of our explorative studies on the synthesis of tin oxide carbodiimide (Sn 2 O(CN 2 ) [20] ) and tin oxide chloride carbodiimide (Sn 9 O 5 Cl 4 (CN 2 ) 2 [21] ) compounds some unknown side phases were detected when departing from SnX 2 (X=Cl, Br, I). Some of these side phases were investigated and identified as tin oxide halides.…”

“…The discovery of these compounds allows their use in the synthesis of mixed carbodiimide compounds such as Sn 9 O 5 Cl 4 (CN 2 ) 2 [21] as successfully prepared from an appropriate mixture of Li 2 (CN 2 ) and Sn 7 O 4 Cl 6 at 400 °C.…”

“…The ELF measures the probability of finding an electron at the same point in space as a reference electron with the same spin; therefore areas with high ELF values have high electron localization and are associated with electron pairs [23] . The ELF is particularly useful for understanding the behavior of the Sn 2+ lone pair [21,24] …”

“…[11] Our attempts to reproduce these compounds failed. Furthermore, von Schnering et al reported the crystal structure of a so called "basic tin chloride", structurally characterized as Sn 21 Cl 16 (OH) 14 O 6 . [12] When heating this compound, several decomposition products were obtained, assigned as Sn 21 Cl 16 O 13 and Sn 9 Cl 4 O 7 , however, without crystal structure data.…”