The substitutional chemistry of MgB2

A brief summary is given of the current status of chemical substitution experiments in MgB2. Analysis of the data in the literature shows that only in a handful of cases has partial substitution of an atom for Mg or B been substantiated. These cases are Al and Mn substitution for Mg, and C substitution for B. C and Al substitution have received the most attention. Oxygen incorporation is an interesting chemical issue. A summary of our work on the Mg1-xAlxB2 system is presented