Etude de la tétracoordination de l'etain dans deux orthothiostannates: Na4SnS4 et Ba2SnS4 (α)

The crystal structure of La2SnS~ has been determined by X-ray diffraction methods. The space group is Pbam and the cell constants are a= 11.22, b=7.915, e=3-96 ~ and Z=2. The structure was solved by direct methods with the LSAM program and refined by a least-squares program to a final R va'lue of 0.064 for 1751 reflexions. The lanthanum atoms are nine-coordinated and the tin atoms are sixcoordinated.

Section: Resultsunclassified

Structure cristalline du sulfure d'étain et de lanthane, La2SnS5

Jaulmes¹

1974

“…11). In Na4SnS4, for example, the tetrahedral bond was found to be 2.388(4) A (Jumas, Vermot-Gaud-Daniel & Philippot, 1973).…”

Section: Discussionmentioning

confidence: 99%

“…SnS2 has a layer structure, while the latter two compounds have structures related to each other with double chains of SnS6 octahedra sharing edges. Tetrahedral coordination has been found in Ba3Sn2S7, Na6SnzS7 (which is isomorphous with Na6Ge2S7) (Jumas, Olivier-Fourcade, Vermot-Gaud-Daniel, Ribes, Philippot & Maurin, 1974), Na4SnS4 and Ba2SnS4(~), (Jumas, Philippot, Vermot-Gaud-Daniel, Ribes & Maurin, 1974), and Ba2SnSa(fl) (Susa & Steinfinck, 1971). A recent study of NaaSn3S8 , on the other hand, has revealed both four-and fivefold coordinated tin(IV).…”

Section: Introductionmentioning

confidence: 99%

The OD structure of Na2SnS3. Determination and refinement of an MDO structure

Mark¹,

Lindqvist²,

Jumas³

et al. 1974

Na2SnSa crystallizes with an OD structure. The family reflexions define a superposition structure, space group R3m, with A = B= 3.834 (2), C= 19.88 (1) ,&, Z= 2. The superposition structure was solved fromPatterson and electron-density calculations and refined to an R of 0.046. From this structure it is apparent that Na2SnS3 is of NaC1 type, with the tin and sodium atoms distributed over the cation positions.The real structure consists of ordered layers parallel to the ab plane. These are composed of two closepacked planes of sulphur atoms between which the sodium and tin atoms occupy -} and ~ of the octahedral holes, respectively. Between two such planes there are sodium atoms in all the octahedral holes. The disorder arises since each layer can be orientated in three different ways with respect to its predecessor. It is possible to define six structures of maximum degree of order, MDO1-MDO6, corresponding to pronounced maxima on the continuous reciprocal streaks. These can all be described by a hexagonal cell with a=b= 6.633 (3), c= 39.76 (2)/~, and Z= 12. Intensities corresponding to one such MDO structure have been measured, thus making it possible to refine the atomic parameters of the ordered layers (R=0.045 for 314 independent intensities). Both tin and sodium have slightly distorted octahedral coordination. All six Sn-S distances are 2.571 (2) ~, while the Na-S distances range from 2.735 (3) to 2.980 (3)/~.

“…Comme il 6tait pr6visible, cette valeur de 3,392 A est 16gbrement sup6rieure /t celle rencontr6e pour leg poly6dres (Ba-75) (Ba-S=3,31 A dang BazSnS4; Jumag, Philippot, Daniel, Ribes & Maurin, 1975) et (Ba-6S) (Ba-S= 3,24 A dang Ba3Sn2S7; Jurnas, Olivier-Fourcade, Vermot-Gaud-Daniel, Ribeg, Philippot & Maurin, 1974). Enfin on peut remarquer dang la Fig.…”

Section: Tableau 6 Dbtances (A) Et Angles (O) Moyens Dans Les Difforunclassified

Structure cristalline d'un thiotellurite de baryum BaTeS₃. Comparaison avec d'autres groupements TeX ₃

Jumas¹,

Ribes²,

Maurin³

et al. 1976

Self Cite

BaTeS3 is orthorhombic, space group Prima with cell constants a = 7.490 (5), b = 6"898 (4), c = 10.946 (6) A, and Z= 4. The structure was solved by means of Patterson and Fourier syntheses and refined by the least-squares method. The final R value is 0.027. The structure is characterized by discrete TeS~-pyramids and is compared with other similar groups: TeX3 (with X = O or CI). The likely situation of the lone pair is discussed.