Structural Properties of REM$\text{}_{2}$Sn$\text{}_{2}$ (RE=La, Ce and M=Ni, Cu)

The lattice parameters a and c of CeM$\text{}_{2}$Sn$\text{}_{2}$ show an anomalous temperature dependence compared to the analogous variations for LaM$\text{}_{2}$Sn$\text{}_{2}$. The anomaly Δa of thermal expansion for CeCu$\text{}_{2}$Sn$\text{}_{2}$ has a maximum around 90 K, whereas Δc has a maximum near 140 K, near to the maximum of the magnetic resistivity Δρ