X-ray diffraction characteristics of new chromitomanganites LaM (3) (I) CrMnO6 and LaM (3) (II) CrMnO7.5 (M-I = Li, Na; M-II = Mg, Ca)

Abstract

LaM (3) (I) CrMnO6 (M-I = Li, Na) and LaM (3) (II) CrMnO7.5 (M-II = Mg, Ca) chromitomanganites were synthesized by ceramic technology from lanthanum oxide, chromium(III) oxide,manganese(III) oxide, lithium carbonate, sodium carbonate, magnesium carbonate, and calcium carbonate. X-ray powder diffraction shows that these compounds crystallize in cubic or tetragonal systems with the following unit cell parameters: for LaLi3CrMnO6 (cubic): a = 10.98 , V (au <) = 1323.75 (3), Z = 8, V (u.c) (au <) = 165.47(3), rho(X) = 3.64, rho(pycn)= 3.60 +/- 0.04 g/cm(3); for LaNa3CrMnO6 (tetragonal): a = 10.96 , c = 15.73 , V (au <) = 1889.51 (3), Z = 16, V (u.c) (au <) = 118.09 (3), rho(X) = 5.77 g/cm(3), rho(pycn) = 5.70 +/- 0.07 g/cm(3); LaMg3CrMnO7.5 (cubic), a = 10.98 , V (au <) = 1322.31 (3), Z = 8, V (u.c) (au <) = 165.29 (3), rho(X) = 4.41 g/cm(3), rho(pycn) = 4.35 +/- 0.07 g/cm(3); and for LaCa3CrMnO7.5 (cubic): a = 10.97 , V (au <) = 1319.78 (3), Z = 8, V (u.c) (pO) = 164.97 (3), rho(X) = 4.89 g/cm(3), rho(pycn) = 4.85 +/- 0.05 g/cm(3).