Bonds the scales disagree about

One of the figures on a basis is not a thing: The same electrons written two ways with the density unchanged, and four electronegativity scales that disagree.

Four essays draw this figure, each at the values its own argument needs rather than at the setting shown above. What each one uses it to show is below, in the words of its own caption.

Electronegativity is not one quantity

Every ordinary bond tested whose polarity direction is disputed between the four scales. Each row is a bond that would be drawn with the arrow pointing in opposite directions depending on which of four tables in common use was consulted.

A ranking is not a difference

Which atom each of four scales calls the more electronegative, for a list of ordinary bonds. Every row where the columns disagree is a bond whose polarity would be drawn in opposite directions depending on which table was consulted.

The same comparison restricted to the two scales that disagree most. Twelve pairs of elements out of a hundred and fifty-three are ranked in opposite orders by these two, and the bonds among them are ordinary ones.

The two scales that agree best, taken alone. Pauling against Allen leaves a much shorter list of disputed bonds than the full set of four does — but it is not empty, and the bonds on it are ordinary ones. A pair of scales chosen for agreement still disagrees about the direction of a bond somebody draws.

A difference does not make a transfer

The bonds this site’s four scales already disagree about, before any of the above is taken into account. Six ordinary bonds have a disputed direction of polarity, C–H among them. The argument here adds a second, independent reason to be careful with the magnitude even where the direction is agreed.

A mean that is low rather than right

Why the fifth of an electronvolt the whole family spans is not the largest uncertainty in sight: ordinary bonds whose polarity direction is disputed between published scales. A rule accurate to a tenth of an electronvolt is being fed inputs that disagree about which way the charge goes.