Miss Naeema... You need to start with the metal nitrates at the right amounts that give the desired mole ratios and dissolve them in water, followed by precipitation with NaOH solutions. There will be a mixture of the hydroxides which will give the mixed oxide you need by heating in a furnace at a temperature higher than 500 C until a constant weight is obtained. If you tell me about the final weight of the mixed oxide I may give you more details about the procedure... Regards

sir mahood

i want to know generally how to take the stoichiometric ratio of precursors to statrt an experiment?

i.e how much grams of a nitrate i have to take?

Miss Naeema... You need to give me the exact weight you like to prepare from the mixed oxide composite. For the required formula (CoFe1.7Mn.3O4) weigh out 1.0 mole of the Co nitrates, 1.7 mole of Fe nitrate, and 3.0 mole of Mn nitrate and dissolve them in water. If the total amount of the mixed oxide is less than this you may divide the weights by 10 or 5 as necessary. I gave you the general case and the exact weight values is your decision. You may then proceed by adding NaOH solution to precipitate the hydroxides. This will give the mixed oxide you need by heating in a furnace at a temperature higher than 500 C until a constant weight is obtained. ... Regards

Please follow the following procedure

1) Prepare 50 mL of 0.1 M solution of Cobalt nitrate/acetate, 0.2 M solution of iron nitrate and 0.2 M solution of Manganese nitrate/acetate.

2) Now mix 50 mL of cobalt nitrate/acetate solution, 48.5 mL of iron nitrate solution and 1.5 mL of Maganese nitrate/acetate solution into a single container.

Your required metal composition is ready. Now you can precipitate out the metals as mixed metal hydroxide using 0.2 M NaOH as a precipitating agent. Then anneal in furnace at 1073 K for three hours to obtain CoFe1.7Mn0.3O4.

thanks to all.