  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.
