The CRC Elecrochemical Series and the solution to our exercise suggest that the oxidation states of borohydride are -V for Boron and +I for Hydrogen.
Since H (2.2) is more electronegativ than B (2.0), I would have expected the oxidation states to be +III for B and -I for H.
What am I missing here?
The solution to our exercise lists this (WARNING: it turned out that the solution was wrong):
And the CRC Elecrochemical Series lists this (also suggesting -V for B):