TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: In the method (M1), chemical vapor deposition, atomic layer deposition or physical vapor deposition is used. The ionic liquid comprises a salt, liquid under the process conditions, selected from salts formed by the reaction of at least one amine salt of the formula R1R2R3R4N+X- (I) with at least one hydrated salt, which is a chloride, nitrate, sulphate or acetate of Lithium, Magnesium, Calcium, Chromium, Manganese, Ferrous, Cobalt, Nickel, Copper, Zink, Cadmium, lead, bismuth, lanthanum or cerium. The cation or salt is evaporated using film evaporation (e.g. using a spinning disc) or a ceramic membrane module. The concentration of the cations in the liquid is regulated by controlling the electrical current through the anode. A sensor for the cation the molecule of the cation and the anion is used to measure the concentration of the cation or the molecule of the cation and the anion in the vapor from the liquid and controlling the electrical current with a result of the measurement. The electrically conductive liquid is an aqueous solution of a salt 0.01 (preferably 0.1) M. A layer is deposited having an average layer thickness of 0.01nm to 3 mm (preferably 0.1 nm to 10 mu m, especially 0.1-100 nm, particularly 0.1-10 nm.R1 to R3=1-5C alkyl or 6-10C cycloalkyl;orR2+R3=4-10C alkylene, forming 5-11 membered heterocyclic ring with the N atom of formula (I);R4=phenyl, 1-12C alkyl or cycloalkyl (all optionally substituted by -OH, -Cl, -Br, -F, -I, -phenyl, -NH2, -CN, -NO2, -COOR5, -CHO, -COR5, and -OR5;R5=1-10C alkyl or cycloalkyl;andX=anion capable of being complexed by hydrated salt.Preferred Components: The anode comprises at least one element selected from metals and metalloids, preferably from Hf, Zr, Ti, Al, Cu, Mo, Ta, W, Si, Ru, Ge, Ba, Ca, Sr, Co, Mg, Sn, Pt, Pd, Au and As. The anions are selected from halogen ions, in particular from chloride, bromide and iodide. The liquid is an ionic liquid. The ionic liquid comprises a salt, liquid under the process conditions, selected from salts formed of at least one of the cations selected from monosubstitued imidazolium, disubstituted imidazolium, trisubstituted imidazolium, pyridinium, pyrrolidinium, phosphonium, ammonium, guanidinium, tri-substituted sulphonium and/or isouronium; and at least one of the anions selected from chloride, bromide, iodide, nitrate, nitrite, fluoride, phosphate, imide, amide, borate, tosylate, tetrafluoroborate, hexafluoroborate, hexafluorophosphate, trifluoromethanesulphonate, methylsulphate, bis(pentafluoroethyl)phosphinate, thiocynate, octylsulphate, hexylsulphate, butylsulphate, ethylsulphate, dicyanamide, hexafluoroantimonate, bis-(pentafluoroethyl)phospinate, bis-(trifluoromethyl)imide, trifluoroacetate, bis-trifluorosulphonimide, and dicyanamide.    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - The apparatus comprises a first container; and a salt bridge for allowing ions from electrically conductive liquid to be transported from container to a film evaporator in the form of a second container for holding electrically conductive liquid, where film evaporator comprises an anode, which anode comprises electrolytically ionisable material. EXAMPLE - No suitable example given.