  Ba2CaMoO6 was synthesized by solid state method. The crystal structure adopts
cubic Fm-3m space group at room temperature with lattice parameters of
8.378231(5) {angstroms}. Upon cooling, Ba2CaMoO6 was determined to have a
structural phase transition to tetragonal I4/m (a=5.905763(6) {angstroms} and
c=8.38817(1) {angstroms}) around 200 K. The phase transition was probed
structurally by synchrotron and neutron diffraction and thermodynamically by
specific heat and differential scanning calorimetry measurement. This
structural phase transition will deepens our understanding of the perovskite
family especially the formation of perovskites that break corner sharing
networks.
