Biologically active compounds of semi-metals

The present state of knowledge in the chemistry of organic compounds of semi-metals from different organisms is reviewed. They include, e.g., the boron-containing antibiotics or the silicon compounds present in “silicate” bacteria. Arsenic is incorporated into arsenosugars, arsenobetaines or volatile methylated arsenic compounds, selenium is incorporated into selenocysteine that is found in some proteins. Other metalloids, i.e. the rare and toxic tellurium and the radioactive short-lived astatine, have no biological significance.