  The liquid structure of a glass-forming binary alloy is studied using
molecular dynamics simulations. The analysis combines common neighbour analysis
with the geometrical approach of Frank and Kasper to establish that the
supercooled liquid contains extended clusters characterised by the same short
range order as the crystal. Fluctuations in these clusters exhibit strong
correlations with fluctuations in the inherent structure energy. The steep
increase in the heat capacity on cooling is, thus, directly coupled to the
growing fluctuations of the Frank-Kasper clusters. The relaxation of particles
in the clusters dominates the slow tail of the self-intermediate scattering
function.
