Chrysiogenes arsenatis is a species of bacterium given its own phylum, called the Chrysiogenetes. It has a unique biochemistry. Instead of respiring with oxygen, it respires using the most oxidized form of arsenic, arsenate. It uses arsenate as its terminal electron acceptor. Arsenic is usually toxic to life. Bacteria like Chrysiogenes arsenatis are found in anoxic arsenic-contaminated environments.