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:

Essential oils of Thymus leucospermus Hartvig, a Greek endemic rich in phenolic monoterpenes. Thymus leucospermus Hartvig is a Greek endemic species of Section Teucrioides Jalas. The essential oils obtained from five populations growing wild in the National Park of Northern Pindhos (NW Greece) were studied. The oil content ranged between 1.1 and 2.0 mL per 100 g of dry plant weight. The oils were particularly rich in phenolic monoterpenes: they had a high thymol (64.7-92.0%) or carvacrol (93.4%) content, whereas in one of the oils considerable amount of both compounds was found (thymol 61.6% and carvacrol 26.4%). Our results show that T. leucospermus is a high-quality thyme species, with respect to both oil content and composition.
{"Chemical": ["thymol", "phenolic monoterpenes", "carvacrol"]}