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:

Preparation, preliminary screening of new types of steroid conjugates and their activities on steroid receptors. There were synthesized new types of ribbon type steroidal dimers derived from three types of steroidal skeletons (cholic acid, etienic acid, estrone) using Cu(I) catalyzed 1, 3-dipolar cycloaddition reaction. Steroid parts of the molecular "ribbons" are linked by heterocyclic moiety, namely by 2,6-bis((1H-1,2,3-triazol-1-yl)-methyl)pyridine. Compounds synthesized possess different cytotoxic and hormone receptor modulating activities.
{"Chemical": ["estrone", "Cu(I)", "Steroid", "2,6-bis((1H-1,2,3-triazol-1-yl)-methyl)pyridine", "cholic acid", "steroid", "etienic acid"]}