(NL9302030-A)      Adducts of lanthanide beta-diketones and donor ligands suitable for use in a metal-contg. material deposition process, in which the donor ligand has Lewis base characteristics that match the Lewis acid characteristics of the lanthanide beta-diketone in the absence of the donor ligand.    Also claimed is metal-contg. material deposition process using a lanthanide beta-diketone complex having the above characteristics.    Pref. the donor ligand is neutral, pref. an oxide, esp. an N-oxide and esp. pyridine N-oxide and the lanthanide is pref. Y.    USE -   The cpds. are useful in metal-organic chemical vapour deposition (MOCVD) processes (claimed), e.g. for mfr. of opto-electronic materials, and for the deposition of mixed metal oxides which are superconducting at relatively high temps., of buffer layers, of anode and electrolyte materials for fuel cells and of magnetic oxides.    ADVANTAGE -   The problems of dissociation and hydrolysis of lanthanide beta-diketonates or the Lewis base adducts during MOCVD are avoided. The cpds. are liq. in use and therefore have a constant surface area exposed, in contrast to prior materials which are typically non-uniform particulates. The lanthanide (beta-diketone) ligand adduct has a m.pt. of less than 150 C, esp. less than 125 C and esp. less than 100 C (claimed).    (DE4499144-T)      Adducts of lanthanide beta-diketones and donor ligands suitable for use in a metal-contg. material deposition process, in which the donor ligand has Lewis base characteristics that match the Lewis acid characteristics of the lanthanide beta-diketone in the absence of the donor ligand.    Also claimed is metal-contg. material deposition process using a lanthanide beta-diketone complex having the above characteristics.    Pref. the donor ligand is neutral, pref. an oxide, esp. an N-oxide and esp. pyridine N-oxide and the lanthanide is pref. Y.    USE -   The cpds. are useful in metal-organic chemical vapour deposition (MOCVD) processes (claimed), e.g. for mfr. of opto-electronic materials, and for the deposition of mixed metal oxides which are superconducting at relatively high temps., of buffer layers, of anode and electrolyte materials for fuel cells and of magnetic oxides.    ADVANTAGE -   The problems of dissociation and hydrolysis of lanthanide beta-diketonates or the Lewis base adducts during MOCVD are avoided. The cpds. are liq. in use and therefore have a constant surface area exposed, in contrast to prior materials which are typically non-uniform particulates. The lanthanide (beta-diketone) ligand adduct has a m.pt. of less than 150 C, esp. less than 125 C and esp. less than 100 C (claimed).    (GB2298203-B)      Adducts of lanthanide beta-diketones and donor ligands suitable for use in a metal-contg. material deposition process, in which the donor ligand has Lewis base characteristics that match the Lewis acid characteristics of the lanthanide beta-diketone in the absence of the donor ligand.    Also claimed is metal-contg. material deposition process using a lanthanide beta-diketone complex having the above characteristics.    Pref. the donor ligand is neutral, pref. an oxide, esp. an N-oxide and esp. pyridine N-oxide and the lanthanide is pref. Y.    USE -   The cpds. are useful in metal-organic chemical vapour deposition (MOCVD) processes (claimed), e.g. for mfr. of opto-electronic materials, and for the deposition of mixed metal oxides which are superconducting at relatively high temps., of buffer layers, of anode and electrolyte materials for fuel cells and of magnetic oxides.    ADVANTAGE -   The problems of dissociation and hydrolysis of lanthanide beta-diketonates or the Lewis base adducts during MOCVD are avoided. The cpds. are liq. in use and therefore have a constant surface area exposed, in contrast to prior materials which are typically non-uniform particulates. The lanthanide (beta-diketone) ligand adduct has a m.pt. of less than 150 C, esp. less than 125 C and esp. less than 100 C (claimed).    (US5837321-A)      Adducts of lanthanide beta-diketones and donor ligands suitable for use in a metal-contg. material deposition process, in which the donor ligand has Lewis base characteristics that match the Lewis acid characteristics of the lanthanide beta-diketone in the absence of the donor ligand.    Also claimed is metal-contg. material deposition process using a lanthanide beta-diketone complex having the above characteristics.    Pref. the donor ligand is neutral, pref. an oxide, esp. an N-oxide and esp. pyridine N-oxide and the lanthanide is pref. Y.    USE -   The cpds. are useful in metal-organic chemical vapour deposition (MOCVD) processes (claimed), e.g. for mfr. of opto-electronic materials, and for the deposition of mixed metal oxides which are superconducting at relatively high temps., of buffer layers, of anode and electrolyte materials for fuel cells and of magnetic oxides.    ADVANTAGE -   The problems of dissociation and hydrolysis of lanthanide beta-diketonates or the Lewis base adducts during MOCVD are avoided. The cpds. are liq. in use and therefore have a constant surface area exposed, in contrast to prior materials which are typically non-uniform particulates. The lanthanide (beta-diketone) ligand adduct has a m.pt. of less than 150 C, esp. less than 125 C and esp. less than 100 C (claimed).