You will be shown an abstract from a materials science research paper. Your task is to extract all synthesis operations described in the abstract into a structured JSON format. Your output should be a JSON array. Each entry in the array should be a JSON object describing a single synthesis operation. This object should have the following fields:

- "trigger": A verbal predicate indicating a synthesis operation. This should be a string extracted directly from the abstract.
- "arguments": An array of arguments specifying aspects of the synthesis operation. Each entry in the array should be a length-2 array formatted as [<argument_text>, <argument_type>]. The `argument_text` should be a string extracted directly from the abstract. The `argument_type` should be one of the following types: ["Recipe_Precursor", "Atmospheric_Material", "Participant_Material", "Recipe_Target", "Solvent_Material"].

For instance, suppose an excerpt from the abstract reads:

Tetraethoxysilane (TEOS, 98%) and cetyltrimethylammonium bromide (CTAB, 98%) were purchased from Fluka. The MTTZ-siloxy derivative (triethoxysilyl-propyl-5-mercapto-1-methyl-tetrazole) was synthesized as previously described [38].

This excerpt includes two operations, which could be annotated as follows.

[{"arguments": [["Tetraethoxysilane", "Recipe_Precursor"], ["cetyltrimethylammonium bromide", "Recipe_Precursor"]], "trigger": "purchased"}, {"arguments": [["MTTZ-siloxy derivative", "Recipe_Target"]], "trigger": "synthesized"}]

In your response, please include the JSON and no other text.

Abstract:
10.1016/j.jpowsour.2015.12.048
Synthesis of sub-10 nm copper sulphide rods as high-performance anode for long-cycle life Li-ion batteries

Copper acetate monohydrate (analytical reagent (AR)), pyridine (AR), and sodium sulfide nonahydrate (AR) were purchased from Sigma-Aldrich. The electrolyte was purchased from Guo Tai Hua Long Company, including 1 M LiPF6 in ethylene carbonate (EC) and dimethyl carbonate (DMC) (1:1 by volume). All chemicals were used without further purification.

In a typical synthesis, 5.0 mmol of copper acetate monohydrate was dissolved into 40 mL distilled water/pyridine mixture (v:v = 1:3) and heated to 80 degC. 5.0 mmol of sodium sulfide nonahydrate was dissolved into 20 mL of distilled water. Then, sodium sulfide solution was dropped into copper acetate solution under vigorous stirring. Finally, the mixture reacted for 2 h at 80 degC. The final products was collected and washed several times by distilled water or other solvents (e.g., ethanol, pyridine), and then dried in a vacuum at 60 degC for 12 h.
[{"arguments": [["Copper acetate monohydrate", "Recipe_Precursor"], ["sodium sulfide nonahydrate", "Recipe_Precursor"], ["pyridine", "Solvent_Material"]], "trigger": "purchased"}, {"arguments": [["electrolyte", "Participant_Material"], ["LiPF6", "Participant_Material"], ["ethylene carbonate", "Solvent_Material"], ["dimethyl carbonate", "Solvent_Material"]], "trigger": "purchased"}, {"arguments": [["chemicals", "Participant_Material"]], "trigger": "used"}, {"arguments": [["water", "Solvent_Material"], ["pyridine", "Solvent_Material"], ["copper acetate monohydrate", "Recipe_Precursor"]], "trigger": "dissolved"}, {"arguments": [["sodium sulfide nonahydrate", "Recipe_Precursor"], ["water", "Solvent_Material"]], "trigger": "dissolved"}, {"arguments": [["copper acetate", "Recipe_Precursor"], ["sodium sulfide", "Recipe_Precursor"]], "trigger": "dropped"}, {"arguments": [["mixture", "Participant_Material"]], "trigger": "reacted"}, {"arguments": [["products", "Participant_Material"]], "trigger": "collected"}, {"arguments": [["ethanol", "Solvent_Material"], ["solvents", "Participant_Material"], ["pyridine", "Solvent_Material"], ["water", "Solvent_Material"]], "trigger": "washed"}]