International authority
IUPAC Periodic Table of the Elements
Used for atomic numbers, official symbols, official English names, periods, and uncontested group placement.
Open IUPAC sourceSource architecture
Sources and display notes
External scientific authorities and Mimetic Matter display conventions are kept distinct.
International authority
CIAAW Standard Atomic Weights 2024
Used for standard atomic weights. Interval and uncertainty notation are preserved. An em dash indicates that CIAAW publishes no standard atomic weight.
Open CIAAW sourceOpen IUPAC question
Constitution of Group 3
The public reference layout uses neutral lanthanoid and actinoid series placeholders rather than asserting one final Group 3 convention.
Open IUPAC projectGoverned internal convention
Mimetic Matter display conventions
The s/p/d/f block labels, element-category taxonomy, alternate arrangements, lenses, and visual layers are Mimetic Matter organizational choices. They are not presented as IUPAC classifications.