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Reactivity in the System Copper/Arsenic/Sulfur II. The Formation of CuAsS, (Lautite)
Author(s) -
Müller A.,
Blachnik R.
Publication year - 2003
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.200300116
Subject(s) - arsenic , copper , chemistry , liquidus , reactivity (psychology) , exothermic reaction , thermal decomposition , sulfur , inorganic chemistry , copper sulfide , decomposition , organic chemistry , phase (matter) , medicine , alternative medicine , pathology
The reaction pathways during the synthesis of CuAsS have been studied with the DTA in the range 25 — 810 °C with a heating rate of 10 K/min. Educts, intermediates, and products were characterized by X‐ray diffraction at room and elevated temperatures. Educts were the corresponding elements and the binary compounds As 4 S 4 , As 2 S 3 , Cu 3—x As, Cu 5—δ As 2 , Cu 2 S, and CuS. The 13 examined educt mixtures can be divided into four groups specified by their thermal effects observed during the reaction. Mixtures of group I contain copper arsenides and arsenic sulfides, those of group II and III arsenic and copper sulfides, and arsenic sulfides and copper, respectively. Group IV includes mixtures showing individual reactions. In all cases the reaction to CuAsS proceeds stepwise. The reaction is not completed at 574 °C, the decomposition temperature of CuAsS, because the product is still associated with Cu 12+x As 4+y S 13 , As, and to a lesser amount with Cu 1.81 S. Nevertheless, a consecutive run in which the samples were heated above the liquidus temperature shows no exothermic reaction effect. When the mixtures were cooled at 10 K/min after the runs, no CuAsS was found in the X‐ray experiments. Only Cu 12+x As 4+y S 13 and As were then observed.