Lattice parameters of RMn2Si2 and RMn2Ge2 compounds

The ternary compounds of the rare earths with Mn and Si in the stoichiometric ratio 1:2:2 have been prepared and studied by X-ray analysis. They were found to be of the tI10 Al4Ba-ThCu2Si2 structure type. A number of the previously known isostructural RMn2Ge2 compounds have also been prepared. The molar volumes of these phases are compared with those of other similar groups of compounds and are briefly discussed. (Auth.)