has role osmium coordination entity fixative oxidising agent poison histological dye osmium tetroxide Perosmic oxide Perosmic acid anhydride Osmic acid VUVGYHUDAICLFK-UHFFFAOYSA-N An osmium coordination entity consisting of four oxygen atoms bound to a central osmium atom via covalent double bonds. chebi_ontology PMID:25871651 PMID:23975065 InChI=1S/4O.Os O4Os 254.222 0 O=[Os](=O)(=O)=O tetraoxoosmium Osmium oxide Reaxys:11406415 CAS:20816-12-0 CHEBI:88215 Wikipedia:Osmium_tetroxide 255.94114 PMID:12530969 Osmic acid anhydride Osmium tetraoxide