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Synthesis and Structure of Cs 2 [As(CH 3 )Se 3 ] · 2H 2 O and Cs 2 As 4 Se 6 containing the Catena‐hexaselenidotetraarsenate(II, III) Anion $^{1}_{\infty}\rm [As_{4}Se_{6}^{\phantom{\infty}2-}]$
Author(s) -
van Almsick Tobias,
Sheldrick William S.
Publication year - 2006
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.200600028
Subject(s) - crystallography , chemistry , caesium , ion , envelope (radar) , symmetry (geometry) , bond length , crystal structure , ring (chemistry) , tetrahedron , stereochemistry , inorganic chemistry , geometry , mathematics , telecommunications , radar , organic chemistry , computer science
Heating CsAsSe 3 · 0.5H 2 O in methanol to 190 °C leads to formation of black Cs 2 As 4 Se 6 ( 1 ) together with red Cs 4 As 4 Se 8 and a colourless solution from which the substituted caesium selenidoarsenates(V) Cs 2 [As(CH 3 )Se 3 ] · 2H 2 O ( 2 ) and Cs[As(CH 3 ) 2 Se 2 ] can be obtained as crystalline fractions. Cs 2 As 4 Se 6 contains catena‐hexaselenidotetraarsenate(II,III) anions in which cyclic As 3 Se 5 units are linked through corner‐sharing AsSe 3 pyramids into infinite chains $^{1}_{\infty}\rm [As_{4}Se_{6}^{\phantom{\infty}2-}]$ . The C s symmetric As 3 Se 2 five‐membered rings of the As 3 Se 5 units display an envelope conformation with an As‐As bond length 2.528(3) Å and As‐Se distances of 2.449(2) and 2.447(2) Å. C s symmetry is also observed for the discrete tetrahedral [As(CH 3 )Se 3 ] 2− anions of ( 2 ).