Compounds that are heteroatom substituted alkyl derivatives of tricyclodecan-9-yl-xanthogenate, and pharmaceutical compositions of these compounds, are disclosed. Methods of treating a disease or disorder in a subject and methods of protecting normal tissues in a subject from toxicity associated ionizing radiation or chemotherapy using compositions comprising these novel compounds are also disclosed. The invention also concerns methods of treating a disease or disorder in a subject using compositions that include these novel compounds while concurrently or consecutively treating the subject with ionizing radiation or a chemotherapeutic agent.