Structures of tetrathallium(I) tetrathiosilicate(IV) and tetrathallium(I) tetraselenosilicate(IV)
- Publication Type
- Journal contribution
- Authors
- Eulenberger, G.
- Year of publication
- 1986
- Published in
- Acta Crystallogr., Sect. C: Cryst. Struct. Commun.
- Band/Volume
- C42/5
- Page (from - to)
- 528-34
Tl4SiS4 is monoclinic, space group Cc, with a 12.518(3), b 11.241(2), c 7.567(2) .ANG., and .beta. 112.802).degree.; Z = 4 for dc ; 6.59. The final R = 0.066 for 883 reflections. Tl4SiSe4 is monoclinic, C2/c, with a 11.664(9), b 7.277(4), c 24.903(12) .ANG., and .beta. 99.93(5).degree.; Z = 8 for dc = 7.41. The final R =0.064 for 866 reflections. Tl4SiS4 is isostructural with Tl4GeS4 and contains SiS44- anions held together by Tl+ cations in irregular 6-fold coordination. The relations between the structures of Tl4SiS4, tetragonal Na4SnS4, and Tl4SnS4 are discussed. Tl4SiSe4 is built up from slabs parallel to (001) which consist of almost planar 36 nets of Tl+ cations enclosed between 2 parallel layers of SiSe44-tetrahedra. Further Tl+ cations are located in voids between the SiSe44- tetrahedra of each layer and between the slabs. The Tl atoms in 3 general and 2 special positions are coordinated to essentially 6, 5, and 4 Se atoms. The lone pairs of 6s electrons of univalent Tl exhibit strong stereochem. effects with 2 of the Tl atoms. The pseudohexagonal properties of the structure are described by using a group-subgroup relation to a hypothetical hexagonal aristotype. At. coordinates are given.