Dear experts,
I am struggling to calculate the accurate weights of starting precursors to represent the formula Mg0.95Ni0.04Cr0.01O. The precursors are:
1. Mg(NO3)2.6H2O (M.W = 256.4 g/mol), M.W of Mg is 24.305 g/mol which represents about 9.47 %.
2. Ni(NO3)2.6H2O (M.W = 290.8 g/mol), M.W of Ni is 58.69 g/mol which represents about 20.18%.
3.Cr(NO3)3.9H2O (M.W = 400.14 g/mol), M.W of Cr is 51.996 g/mol which represents about 13 %.
I used 0.5 M (0.025 mol) by disolving the precursors in 50 ml water. To represent the chemical formula above, I variate the precursors amount as follow:
1- Mg(NO3)2.6H2O , 0.5 M x 0.95 = 0.475 M, (0.02375 mol). 6.0895 grams, to represent the amount of Mg, 6.0895 x 9.47% = 0.57722 grams,
2- Ni(NO3)2.6H2O, 0.5M x 0.04 = 0.02 M, (0.001 mol). 0.2908 grams, to represent the amount of Ni, 0.2908 x 20.18% = 0.05868 grams.
3- Cr(NO3)3.9H2O, 0.5 M x 0.01 = 0.005 M, (0.00025 mol). 0.100035 grams, to represent the amount of Cr, 0.100035 x 13% = 0.01299 grams.
by summation and dividing the results, I got , 89 % Mg, 9 % Ni, 2 % Cr.
Therefore, when I consider the wt%. , the calculated values do not represent the formula (Mg0.95Ni0.04Cr0.01O) becuase I use the weights of metal nitrate precursor not the bare elements Mg, Ni and Cr. Further, both Ni and Cr are heavier than Mg.
I believe that the quantitaive EDX results will give me very different values.
I used sol-gel method to produce the gel and heat treated at 400 C.
I hope I will get help.
Thanks in advance
Your calculations seem fine to me. I think you'll be pleasantly surprised at your EDX results but let us know if that's not the case.
Dear Dr Greig C. Shearer
I appreciate your kind response to this post and confirming the correctness of my calculations. For sure I will share the results of EDX to help other junior researchers.
Regards,
Mohammed
Mohammed M. Obeid was your way of calculating correct?Because even I need a easy method to calculate amount of precursors needed to form a mixed metal oxide
Mohammed M. Obeid Thank you and good luck to you too for your future work
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