Elastic properties of ternary arsenide SrFe2As2 and quaternary   oxyarsenide LaOFeAs as basic phases for new 38-55K superconductors from first   principles
  Here we report the first-principle FLAPW-GGA calculations of the elastic properties of two related phases, namely, the ternary arsenide SrFe2As2 and the quaternary oxyarsenide LaOFeAs as the basic phases for the newly discovered "1111" and "122" 38-52K superconductors. The independent elastic constants (Cij), bulk moduli, compressibility, and shear moduli are evaluated and discussed. Additionally, numerical estimates of the elastic parameters of the polycrystalline LaOFeAs and SrFe2As2 ceramics are performed for the first time. 
I. R. Shein, A. L. Ivanovskii