You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Serratin a new metabolite obtained from Serratia marcescens, a bacterium isolated from the microflora associated with banana plantations. When cultures of Serratia marcescens, an enterobacteria isolated from the microflora associated with banana plantations incubated at 27°C in a yeast-calcium carbonate-dextrose solid medium (10 g of yeast extract, 20 g dextrose, 15 g bacteriological agar, 20 g calcium carbonate and 1000 mL distilled water) were extracted with chloroform and purified by column chromatography, we obtained a new colourless bacterial metabolite which according to spectroscopic data proved to be serratin.
{"Chemical": ["chloroform", "Serratin", "serratin", "dextrose", "calcium carbonate"]}