  Near the melting temperature, equilibrium bismuth melt is characterized by
structural features that are absent in equilibrium monatomic simple liquids. In
the present work, the structure of bismuth melt is studied by X-ray diffraction
experiments and quantum chemical calculations. The presence of quasi-stable
structures in the melt has been found, the lifetime of which exceeds the
structural relaxation time of this melt. It is shown that these structures are
characterized by a low degree of ordering and spatial localisation. It was
found that up to $50$\% of the atoms in the melt can be involved in the
formation of these structures. The elementary structural units of these
structures are triplets of regular geometry with the characteristic lengths
$3.25$ \AA~and $4.7$ \AA~as well as with the characteristic angles $45^{\circ}$
and $90^{\circ}$. The characteristic lengths of these triplets are fully
consistent with correlation lengths associated with the short-range order in
bismuth melt.
