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:

Tri- and diorganotin(IV) complexes of biologically important orotic acid: synthesis, spectroscopic studies, in vitro anti-cancer, DNA fragmentation, enzyme assays and in vivo anti-inflammatory activities. Tri-and diorganotin(IV) orotates of general formula, R(n)Sn(H(2)Or)(m) [n = 3/2, m = 1/2, R = Me, n-Bu, n-Oct and Ph; H(2)Or(-) = monoanion of orotic acid (H(3)Or)] (n-Bu(2)Sn(HOr) as an exception) have been synthesized. On the basis of various spectroscopic studies it is revealed that R(3)Sn(H(2)Or) and R(2)Sn(H(2)Or)(2) exhibit distorted trigonal-bipyramidal and distorted octahedral geometry, respectively, and n-Bu(2)Sn(HOr) shows both five and six coordination geometry around tin. In vitro anti-cancer screening against MCF-7 (mammary), HEK-293 (kidney), PC-3 (prostate), HCT-15 (colon) and HepG-2 (liver) cancer cell lines suggest that the n-Oct(2)Sn(H(2)Or)(2) is the most active complex among all of the studied complexes. DNA fragmentation and antioxidant enzyme assays suggest that cytotoxic effect of the complexes is selectively mediated through the induction of apoptosis. They also exhibit low toxicity and good anti-inflammatory activity (in vivo).
{"Chemical": ["Ph", "H(2)Or(-)", "R(2)Sn(H(2)Or)(2)", "n-Bu", "R(n)Sn(H(2)Or)(m)", "Tri-and diorganotin(IV) orotates", "Tri- and diorganotin(IV)", "n-Oct", "n-Oct(2)Sn(H(2)Or)(2)", "R(3)Sn(H(2)Or)", "H(3)Or", "n-Bu(2)Sn(HOr)", "orotic acid", "Me"]}