  We have grown intermetallic ErPd$_2$Si$_2$ single crystals employing
laser-diodes with the floating-zone method. The temperature-dependent
crystallography was determined using synchrotron and in-house X-ray powder
diffraction measurements from 20 to 500 K. The diffraction patterns fit well
with the tetragonal $I$4/$mmm$ space group (No. 139) with two chemical formulas
within one unit cell. Our synchrotron X-ray powder diffraction study shows that
the refined lattice constants are $a$ = 4.10320(2) {\AA}, $c$ = 9.88393(5)
{\AA} at 298 K and $a$ = 4.11737(2) {\AA}, $c$ = 9.88143(5) {\AA} at 500 K,
resulting in the unit-cell volume $V$ = 166.408(1) {\AA}$^3$ (298 K) and
167.517(2) {\AA}$^3$ (500 K). In the whole studied temperature range, we did
not find any structural phase transition. Upon cooling, the lattice constants a
and c are shortened and elongated, respectively.
