Table : MAD for line-fits to the data shown in Figure . Comparing the two measures for the total helicality (entries "Total" and "Mean" in Table ), we see that, independent of which approach we choose, both suggest that the HOMO of the metallacumulene shown in Figure deviates more from a cylindrical helix than the HOMO of S -1,9-Me- [8]cumulene; still, in the individual cumulenic parts the deviation is less than that in the polyynes. Comparing the MAD for the fit of the data before and after the ruthenium center ("Before Ru" and "After Ru" entries in Table ), we see that both parts have similar MAD suggesting that the helicality of both sides of the metallacumulene are comparable. This might not be the case for other types of metallacumulenes with a different choice of substituents. The possibility of variable helicality in different parts of a single molecule means that metallacumulenes may make it possible to test how different molecular properties correlate with helicality in separate molecular components (here the ligands). It provides an interesting testbed as many other molecular properties would be kept constant, isolating the impact of helical MOs.