(JP8310802-A)      A prodn process for a perovskite composite oxide ppte comprises adding a fluoride ion scavenger to a mixture of: (1) an aq or hydrofluoric acid soln of a rare earth metal and/or alkaline earth metal M1 fluorocomplex and/or fluoride; and (2) an aq of hydrofluoric acid soln of a transition metal and/or Gp 3B metal M2 fluorocomplex and/or fluoride, to form a ppte of a perovskite composite oxide contg M1 and M2.    Pref M1 is a rare earth metal and M2 is Mn, Co, Cr or K; or M1 is an alkaline earth metal and M2 is Ti; and the fluoride ion scavenger is boric acid.    USE -   For fuel cell electrodes or electrolytes, oxygen sensors, oxygen enrichment membranes, heating elements, catalysts, dielectrics, magnetic substances, superconductors and so forth.    ADVANTAGE -   The prodn method uses a simple device without the need of heating for crystallisation, and is particularly suitable for preparing thin films on large-area and complex shaped substrates.    (US5824278-A)      A prodn process for a perovskite composite oxide ppte comprises adding a fluoride ion scavenger to a mixture of: (1) an aq or hydrofluoric acid soln of a rare earth metal and/or alkaline earth metal M1 fluorocomplex and/or fluoride; and (2) an aq of hydrofluoric acid soln of a transition metal and/or Gp 3B metal M2 fluorocomplex and/or fluoride, to form a ppte of a perovskite composite oxide contg M1 and M2.    Pref M1 is a rare earth metal and M2 is Mn, Co, Cr or K; or M1 is an alkaline earth metal and M2 is Ti; and the fluoride ion scavenger is boric acid.    USE -   For fuel cell electrodes or electrolytes, oxygen sensors, oxygen enrichment membranes, heating elements, catalysts, dielectrics, magnetic substances, superconductors and so forth.    ADVANTAGE -   The prodn method uses a simple device without the need of heating for crystallisation, and is particularly suitable for preparing thin films on large-area and complex shaped substrates.    (CN1150790-A)      A prodn process for a perovskite composite oxide ppte comprises adding a fluoride ion scavenger to a mixture of: (1) an aq or hydrofluoric acid soln of a rare earth metal and/or alkaline earth metal M1 fluorocomplex and/or fluoride; and (2) an aq of hydrofluoric acid soln of a transition metal and/or Gp 3B metal M2 fluorocomplex and/or fluoride, to form a ppte of a perovskite composite oxide contg M1 and M2.    Pref M1 is a rare earth metal and M2 is Mn, Co, Cr or K; or M1 is an alkaline earth metal and M2 is Ti; and the fluoride ion scavenger is boric acid.    USE -   For fuel cell electrodes or electrolytes, oxygen sensors, oxygen enrichment membranes, heating elements, catalysts, dielectrics, magnetic substances, superconductors and so forth.    ADVANTAGE -   The prodn method uses a simple device without the need of heating for crystallisation, and is particularly suitable for preparing thin films on large-area and complex shaped substrates.    (EP761601-B1)      A prodn process for a perovskite composite oxide ppte comprises adding a fluoride ion scavenger to a mixture of: (1) an aq or hydrofluoric acid soln of a rare earth metal and/or alkaline earth metal M1 fluorocomplex and/or fluoride; and (2) an aq of hydrofluoric acid soln of a transition metal and/or Gp 3B metal M2 fluorocomplex and/or fluoride, to form a ppte of a perovskite composite oxide contg M1 and M2.    Pref M1 is a rare earth metal and M2 is Mn, Co, Cr or K; or M1 is an alkaline earth metal and M2 is Ti; and the fluoride ion scavenger is boric acid.    USE -   For fuel cell electrodes or electrolytes, oxygen sensors, oxygen enrichment membranes, heating elements, catalysts, dielectrics, magnetic substances, superconductors and so forth.    ADVANTAGE -   The prodn method uses a simple device without the need of heating for crystallisation, and is particularly suitable for preparing thin films on large-area and complex shaped substrates.