Synthesis and crystal structure of novel proton conductor, RbMg(PO3)3·3(H2O)

electron microscopy. Synchrotron powder diffraction data of the sample were obtained using high resolution powder diffraction beam line (8C1) at Pohang Acceleration Laboratory. In a system of (Ba1xLax)2In2O5+x, two phase boundaries was existed in accordance with x, as shown in below diagram. Rietveld method was used for refining the structure parameter of the (Ba1-xLax)2In2O5+x. The cell parameters of each phase was refined as a=5.94239(2)Å, b= 8.21858(3)Å, c=5.72480(2)Å for LaInO3, a=16.73045(31)Å, b= 6.09718(11)Å, c=5.96295(15)Å for BaIn2O5, and a=4.15398(2)Å for (BaLa)In2O5 respectively. The electrical conductivity of the sintered samples was measured by DC four-probe method. The relationship between the oxide-ion conductivity and crystal structure of (Ba1-xLax)2In2O5+x (0<= x<= 1) will be discussed.