First-principles investigation of the effect of crystal structure on sulfur isotope fractionation in sulfide polymorphs
| Autor: | Yang Guo, Jianming Liu, Yongbing Li, Jie Liu, Tian Gao, Yaolin Shi, Shanqi Liu |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
chemistry.chemical_classification
010504 meteorology & atmospheric sciences Sulfide Coordination number Greenockite engineering.material 010502 geochemistry & geophysics 01 natural sciences Cobaltite Alabandite chemistry.chemical_compound Sphalerite Isotope fractionation chemistry Geochemistry and Petrology engineering Physical chemistry Marcasite 0105 earth and related environmental sciences |
| Zdroj: | European Journal of Mineralogy. 30:1047-1061 |
| ISSN: | 0935-1221 |
| Popis: | In order to study the effect of crystal structure on S isotope fractionation properties of sulfide polymorphs, the reduced partition function ratios of S-34/S-32 (10(3)ln beta(34-32)) for FeS2, CoAsS, ZnS, CdS and MnS polymorphs are calculated in the present study. Our calculations show that 10(3)ln beta(34-32) decreases in the order of pyrite > marcasite > cobaltite > alloclasite > sphalerite approximate to wurtzite > gamma-MnS > hawleyite approximate to greenockite > alabandite. The S coordination number exerts a strong influence on the equilibrium partitioning of S isotopes in these sulfides, and there exist significant S isotope fractionations between the sulfides with different S coordination numbers (CNS), such as alabandite (CNS = 6) and other sulfides (e.g., FeS2, CoAsS, ZnS and CdS polymorphs) (CNS = 4). There is a broad negative correlation between the average bond lengths of all the bonds formed by S and 10(3)ln beta(34-32) values. The compactness of atom packing plays an important role in determining S isotope fractionation properties of sulfides, and S-34 generally tends to concentrate in the phases with higher atomic packing factor (APF). The linear correlation between APF and 10(3)ln beta(34-32) can predict the change of 10(3)ln beta(34-32) with increasing pressure, but pressure has a negligible effect on S isotope fractionation factors between sulfides. |
| Databáze: | OpenAIRE |
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