The current period began in 1980, which is characterised by the high anticipation capacities of its periodic systems (large red square at the top-right corner of Fig. ), with record values of 42 years. This indicates that the periodic system has stayed mostly invariant since the start of this period. By 1980 there was a sharp increase in the number of compounds (Fig. ), especially of transition metals and organogenic elements such as C, N, O, P, S, among a few others. The surge was caused in fact by organometallic chemistry (Extended Data Fig. ). By inspection of the molecular formulas associated with these compounds (), we found that they correspond to a wave of new materials, where research is focused on the physical and chemical properties of solids involving heavy metals, non-metals, and sometimes lanthanoids and actinoids . This includes, for instance, substances developed in high-temperature-superconductor research, catalysis and some other fields .