  First-principles calculations within the DFT are employed to investigate the
relationship between the electronic structure and the unexpected features of
the hexagonal cell parameters of YbAuIn and Yb$_{3}$AuGe$_{2}$In$_{3}$.
Calculations indicate that YbAuIn is an intermediate valent system with one Yb
4\textit{f} state pinned to the Fermi level, while Yb$_{3}$AuGe$_{2}$In$_{3}$
is closer to integer valency with all Yb 4\textit{f} states occupied.
Structural relaxations performed on LaAuIn and LuAuIn analogs reveal that
expansion of the \textit{c}-parameter in Yb$_{3}$AuGe$_{2}$In$_{3}$ is
attributable to larger size of the divalent Yb compared with intermediate
valent Yb.
