Low-temperature specific-heat and electrical-resistivity measurements show that the intermetallic compound ${\mathrm{Al}}_{10}$V has a local soft mode of characteristic temperature 22°K. The behavior is well described by an Einstein model. The number of such modes, taken together with x-ray evidence, indicates that the mode is associated with a loose Al atom occupying a large hole in the ${\mathrm{Al}}_{10}$V structure. This and other peculiarities of the structure provide evidence of important bonding effects.

• Received 22 January 1973

DOI:https://doi.org/10.1103/PhysRevLett.30.1138