The low temperature lattice thermal conductivity of Mg2Sn in the tempe
rature range 4.2-100 K has been analysed. The exact evaluation of rela
xation parameters has been carried out via phonon line widths adopting
the many body technique. The new forms of relaxation times and inclus
ion of force constant change interactions and impurity-anharmonicity i
nteraction modes are the new features of the theory. A fairly good agr
eement between theory and experiments has been presented.