This template produces a color code legend for periodic table templates. Legend of State of matter and natural occurrence are present always. The background-color legend can be set, the default option is the Category color legend.
Column counts are columns only that contain elements. "Compact cells" denote cells with element symbol only, have navbox style and the table fits basic wiki page width (1024×768). "Large cells" have more data, and may cause page width excess (scroll bar added). "Extended" periodic tables are about theoretical periods 8 and higher (element 119 and higher).