For the 1st sample, the contents are: Fe2O3(13.75%),K2O(13.75%),P2O5(13.75%),SiO2(15%),B2O3(30%),MgO(13.75%)
For the 2nd sample, the contents are:
Na2O(3.5%),Fe2O3(13.75%),K2O(13.75),P2O5(13.75%),SiO2(15%),B2O3(30%),MgO(10.38%)
the % refer to %wt
The difference between the two samples is the content of Na2O and MgO.
Hi Mohd,
Without knowing if the fractions your gave are in wt% or at%, a super-detailed answer may not be possible. However, broadly speaking, the impact on the substitution of MgO for Na2O is fairly minimal on the overall network structure of this type of oxide glass. The main structural functions of the two additives you highlight is to form non-bridging oxygens in the atomic network and increase the total free volume, Na2O produces these NBOs at 2X the rate of MgO. However, the FTIR is looking at the relative ratio of different vibrational modes in the glass network, and because the Na and Mg atoms are so close in atomic mass, the exchange of one for the other has little impact on the the allowed phonon frequencies in the lattice.
Cheers,
Dave
Hi Mohd,
Without knowing if the fractions your gave are in wt% or at%, a super-detailed answer may not be possible. However, broadly speaking, the impact on the substitution of MgO for Na2O is fairly minimal on the overall network structure of this type of oxide glass. The main structural functions of the two additives you highlight is to form non-bridging oxygens in the atomic network and increase the total free volume, Na2O produces these NBOs at 2X the rate of MgO. However, the FTIR is looking at the relative ratio of different vibrational modes in the glass network, and because the Na and Mg atoms are so close in atomic mass, the exchange of one for the other has little impact on the the allowed phonon frequencies in the lattice.
Cheers,
Dave
J. David
the % refer to %wt..
thanks for the useful information. I appreciate it
Mr. Kuzaimi, do not expect so much from 1D or 2D FTIR for such systems by coonventional FT techniques. The SiO2 and phosphates showed very intensive bands at about 900-950 and 1240-1300 cm-1. You would thry with derivative analysis of the FT-IR spectra and subtracting procedure (reducing-diifference procedure) of the band at 950 cm-1 . But even by this procedure it has not guarantee that you shall obtain a significant difference even qualitatively.
Why do you say they look the same when clearly they are not ? You don't give the important information as to what resolution you recorded the spectra. Having said that only the OH band at 3435 cm-1 is consistent. The band at 1408 moves to 1392 cm-1 and relatively increases in strength. The band at 1058 cm-1 becomes a doublet with a new band at 1142cm-1 This is not the same. The samples are mainly metal oxides which don't usually give distinctive spectra in the mid IR region unless there is structure or hydrogen bonding features which are sensitive and change with composition.
I agree with David points, You can not able to find differences as absorption band most of small changes overlaps. You are not using difference spectroscopy to may be possible find to these changes as the both metal ions makes same coordination and also the size is more over the same. There is differences at 700 cm-1 regions in same two you have two band one sharp and other almost 5-10 wavenumebr down the shallow band. these are the region where you could see the metal coordination ...;I guess take 2nd derivative of your absorption band that may resolve this band and other changes if is any...
Cheers
Mr. Dent, the peak at 1054 cm-1 ia also a multi-component one. If Kuzaimi perform a curve-fitting procedure, it have min. 3 sub-bands. Furthermore it has also a 'shoulder' ca at 800 cm-1 in both the spectra. It has of the first look only an affected intensity of one of the sub-components at ca. 1055 cm-1. But without derivative analysis, and/or other techniques ffor spectra processing (deconvolution, curve-fitting and more) it is practically unambigouse assignment of any changes of the spectroscopic profile. Especially making the correlation with the structure of one so complex systems. The bands are very overlapped and broad. If Mr. Kuzaimi perform series of spectroscopic measurements at variety of wt% of the components and obtain a representative collection of datasets as well as acxhieved a well determined correlation between the spectroscopic changes and the sub-structural motifs. Than it would be FTIR informative. But definitively only with the classical FTIR techniques without further spectroscopic processing it shall be very difficult for him to evidence the correlation structure-spectroscopic IR-properties
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