Some reseracher caculate stoichiometric amounts (1:1) based on citric acid : metal ions, while other recearcher used (1:1) based on citric acid : nitrate ions.
so how can I calculate Appropriate amount of citric acid in order to prepare LaMnO3 perovskite.
Citric acid forms complex compounds with the most part of metals, and, what is the most important, the ratio M:citric ion is 1:1. tthe complex ions are evenly distributed over the solution, therefore when gel is formed they are as evenly distributed over the gel. This makes the following solid state reaction more profitable - in the ceramic procedure you have the particles about 10 microns in sizes, and here the size of reacting particles is close to molecules. When heated at a rate of about 4 oC per minute to 800 oC the gel decomposes to give thorughly mixed starting material consisting of oxide molecules for the following sintering at higher temperatures. So take this ratio - for 1 mole of La +1 mole of Mn (both dissolved in nitric acid, and pH is then increased to about 6-7 with ammonia) you must take 2 moles of citric acid. Quite easy.
The key roles of citric acid in this process are (1) Chelating agent for metal ions and (2) as organic fuel during the calcination process. If you are maintaining citric acid : metal ions ratio it is meant for effective distribution of metal ions in the citric acid distribution. If you are maintaining citric acid : nitrate ions ratio it is meant for effective combustion of citric acid derivatives.
Citric acid acts as a fuel in preparation of sol-gel auto combustion of many oxides. The exact ratio of metal nitrate to citric acid in case of LaMnO3 should be 1 : 1.66 (according to the principles used in propellant chemistry, the oxidizing and reducing valencies of various elements).
@ prof Chezhina , Singaravelu, Pankaj,
thank you for your kindly reply
@Pankaj
could you please send me the equation for this chemical reaction , also i need a reference about this ratio, if it is possible
thank you in advance
Hello All, I am in the same page of finding the ratio metal ions: citric acid and pH value consideration. I am using NaAcetate, NiAcetate, MnAcetate, CoAcetate as my precursors for sol-gel process. I wanted to synthesize, NaNi1/3Mn1/3Co1/3O2. Kindly share me the references or any opinions. It will be appreciated. Thank you all for your time !!
There must be 1 mole of citric acid per one mole of any component. Sorry? I must frine the reference.
Hi, citric acid also acts as a chelating agent in sol-gel method. The chelating agent helps to bind all metal cations and their presence contributes to lowering reaction temperature. Plus, chelating agent able to destabilized Ba-CO3 interaction.
Can you kindly explain what should be the ratio of citric acid with respect to potassium and Manganese?
I am aiming for K0.5MnO2
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