Some specific metal compounds which may be included in the present invention include TeO₂, Li₂O, Li₂CO₃, Bi₂O₃, Bi₅(OH)₉NO₃)₄, ZnO, Ce₂O₃, CeO₂, Na₂O, Na₂CO₃ and MoO₃.

For example, in some embodiments the present inorganic particle mixture includes substantially crystalline particles of a compound of tellurium, such as tellurium oxide, paratellurite or TeO₂. In some embodiments the present inorganic particle mixture includes substantially crystalline particles of a compound of cerium, such as cerium oxide or CeO₂. In some embodiments the present inorganic (e.g. oxide) particle mixture includes substantially crystalline particles of a compound of bismuth, e.g. bismuth nitrate, or bismuth oxide, dibismuth trioxide, or Bi₂O₃.

The inorganic particle mixture may include two or more different metal compounds, in some embodiments three or more, four or more, five or more or six or more different metal compounds.

The content of the different metal compounds contained may, or course, differ. There may be one, two, three or more metal compounds which have significantly higher content than the other metal compounds contained. For example, in some embodiments the content of the compound of tellurium (e.g. TeO₂) is higher than the content of any other metal compound. In some embodiments, a compound of tellurium and a compound of bismuth are the two compounds with the highest contents—that is, one of a compound of tellurium and a compound of bismuth is the compound with the highest content, and the other is the compound with the second to highest content. The content as used herein may refer to the content by weight.