  Hexagonal and kagome lattices exhibit extraordinary electronic properties. It
is a natural consequence of additional discrete degree of freedom associated
with a valley or the occurence of electronic flat-bands. Combination of both
types of lattices, observed in CoSn-like compounds, leads not only to the
topological electronic behavior, but also to the emergence of chiral phonon
modes. Here, we study CoSn-like compounds in the context of realization of
chiral phonons. Previous theoretical studies demonstrated that the chiral
phonons can be found in ideal two-dimensional hexagonal or kagome lattices.
However, it turns out that in the case of CoSn-like systems with the $P6/mmm$
symmetry, the kagome lattice formed by $d$-block element is decorated by the
additional $p$-block atom. This results in a two dimensional triangular lattice
of atoms with non-equal masses and the absence of chiral phonons in the kagome
plane. Contrary to this, the interlayer hexagonal lattice of $p$-block atoms is
preserved and allows for the realization of chiral phonons. We discuss
properties of these chiral phonons in seven CoSn-like compounds and demonstrate
that they do not depend on atomic mass ratio or the presence of intrinsic
magnetic order. The chiral phonons of $d$-block atoms can be restored by
removing the inversion symmetry. The latter is possible in the crystal
structure of CoGe and RhPb with the reduced symmetry ($P\bar{6}2m$) and
distorted-kagome-like lattice.
