Crystal structure of the new compound Pb{sub 3+x}Sb{sub 3-x}S{sub 7-x}Cl{sub 1+x}(x{approx}0.45): The homologous series Pb{sub (2+2N)}(Sb,Pb){sub (2+2N)}S{sub (2+2N)}(S,Cl){sub (4+2N)}Cl{sub N} and its polychalcogenide derivatives (N=1-3)
- Institut des Materiaux Jean Rouxel (IMN), Universite de Nantes, CNRS, 2 rue de la Houssiniere, BP 32229, 44322 Nantes Cedex 3 (France)
The new chloro-sulfosalt Pb{sub 3+x}Sb{sub 3-x}S{sub 7-x}Cl{sub 1+x} (x{approx}0.45) has been synthesized at 500 deg. C from a mixture of PbS, PbCl{sub 2} and Sb{sub 2}S{sub 3}. It crystallizes in the orthorhombic system (space group Pbam), with a=15.194(3) A, b=23.035(5) A, c=4.0591(8) A, V=1420.6 A{sup 3}, Z=4. The crystal structure has been solved by X-ray single-crystal study, with a final R=0.0497. Deviation from stoichiometric Pb{sub 3}Sb{sub 3}S{sub 7}Cl (x coefficient) follows the substitution rule Sb{sup 3+}+S{sup 2-}{yields}Pb{sup 2+}+Cl{sup -}. Sb and Pb sub-positions within mixed (Sb,Pb) sites are discussed; Pb excess precludes any superstructure along c. A unique pure Cl position is bound only to Pb atoms with a distorted square coordination. The title compound is a rod-type structure derived from the SnS archetype, homeotypic with Pb{sub 6}Sb{sub 6}S{sub 14}(S{sub 3}), where the (S{sub 3}){sup 2-} trimer is replaced by two Cl{sup -}; this substitution is quite isovolumic. Other similar structures are: three polychalcogenides Sr{sub 6}Sb{sub 6}S{sub 14}(S{sub 3}), Pb{sub 6}Sb{sub 6}Se{sub 14}(Se{sub 3}) and Eu{sub 6}Sb{sub 6}S{sub 14}(S{sub 3}); KLa{sub 1.28}Bi{sub 3.72}S{sub 8} and its Ln isotypes; dadsonite, Pb{sub 23}Sb{sub 25}S{sub 60}Cl. Pb{sub 3+x}Sb{sub 3-x}S{sub 7-x}Cl{sub 1+x} is the N=2 member of the homologous series Pb{sub (2+2N)}(Sb,Pb){sub (2+2N)}S{sub (2+2N)}(S,Cl){sub (4+2N)}Cl{sub N}; the N=1 member corresponds to the previously known {approx}Pb{sub 4.3}Sb{sub 3.7}S{sub 8.7}Cl{sub 2.3} compound. Other polychalcogenide derivatives of this homologous series are K{sub 2}Pr{sub 2-x}Sb{sub 4+x}Se{sub 8}(Se{sub 4}) and its Ln isotypes (N=1), as well as SrBiSe{sub 3} (N=3). Such a comparative modular analysis allowed to propose a structural model for the previous synthetic 'Phase Y', {approx}Pb{sub 10}Sb{sub 10}S{sub 23}Cl{sub 4}, corresponding to the combined N=(1+2) homolog. - Graphical abstract: The title compound, Pb{sub 3+x}Sb{sub 3-x}S{sub 7-x}Cl{sub 1+x}, is derived from the homeotypic persulfide Pb{sub 6}Sb{sub 6}S{sub 14}(S{sub 3}) by substituting two chlorine atoms for the S{sub 3} trimer. This change is quite isovolumic.
- OSTI ID:
- 21128265
- Journal Information:
- Journal of Solid State Chemistry, Vol. 181, Issue 4; Other Information: DOI: 10.1016/j.jssc.2008.01.041; PII: S0022-4596(08)00071-6; Copyright (c) 2008 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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