How much different? If it is in the order of % and especially if one structure was measured at RT and second at LT it is quite normal.

Our structure solved at 294 K. Our cell parameters

a = 13.9844(11) Å

b = 10.7695(9) Å

c = 12.2333(10) Å

space group= P21

That research group solved at 100 K. Their cell parameters

a=14.0366(10) Å

b=10.7686(7) Å

c=11.8026(8) Å

space group=Pna21

Your suggestion

You wrote "the same space group" but apparently it is not true.

Cell parameters are quite similar, what was the beta angle?

My bet is that there is a phase transition between 100 and 294 K connected with cell contraction and space group change.

Its orthorhombic alpha=beta=gama=90 degree

there is a change in volume (V) 1842 & 1784

I would like to mention about Cryogenic treatment. When steel is cryotreated, retained austenite gets convereted into martensite. This involves changes in lattice parameters. In addition eta-carbide particles are formed. This has been studied first by R.F. Barron.

Could you please send me the reference of that paper

I think the difference is not high, less than 4 percents along c-direction. So, it can be because of different substrate orientation and temperature. Both parameters can make influence here and make this difference. Try to read about elastic materials.

Respected I. V. Fedorchenko

Thanks for your suggestion. Can i claim this material as a new material or not. otherwise how to i claim. Could you please give me the reference regarding the elastic materials.

Can you say us what kind of compound you investigated, and may be the formula if it is not confidential. I am thinking like Erik Rakosky but to be sure you can make a thermodiffraction analysis if you have the right equipment

Mr. Karunanithi,

1. If your substance and this obtain by the another group yielded the 'same crystal content', meaning the molar ratio of the component and the included solvent, then your results would means that:

1.1. It is possible that youu or your colleagues to solve wrongly the space group and system of the structure. It is shown that another is monocxlinic P21. Each solving at aniothe space group even within the frame of one space system resulted to difference of the a,b,c and V. You could check the validity of your solution or this of your colleagues by PLATON (ADDSYM operation). PLATON is free of charge program available at: http://www.chem.gla.ac.uk/~louis/software/

1.2. If however the crystal content involved different solvent type, than from chemical view point the subbstance is the same, but fron crystallographic one, this is another crystal with similar crystallographic unit cell parameters. 4 % is big difference. Each inclusion of different solvent may effect the self-assembly, crystallization packing, networking, meaning 3D interaction. So that you have different 'crystal' from the same substance. Even at different molar ratio of the component you may 'synthesised' different crystals.

2. It is possible to obtain 'polymorphs' of one crystal content. Meaning that the packing is different depending of the experimental conditions. But the compound is the same. In this case your crystal wmay be 'new polymorph'.

Please account as well tha the measurements at low temperature resulted to low temperature factors, thus allowing a more precise determination of the positions of the atoms in the structure. You are not shown as well another experimental set of parameters and computational details such as number of reflections collected, teta values, R-factors and s.o.

Therefore, If you are sure that your crystalllographic solution is correct, and the collected data are precisely solved in the correct spece group and system, and esdpecially the crystal content is 'same', that you most probably you have new polymorph. Ih however the crystal content is different you have new crystal, and it can be reported in the literature as new.

3. If the crystal content is different nevertheless that the chemical is the same, for examnple different molar ratio acid:base and s.o., that nevertheless how close are the obtained structural parameters (unit cells, and more), this is different crystal. Even it have cases for different chemicals crystallizing 'isostructurally'.

4. If you have the same crystal as content, and you obtain the same space group, same space system, unit cell content as well and more, but your solution yielded more accurate determination of the structural parameters meaning R-factor, that you may also reported your crystal. But not as new one, meaning unknown. It shall be a 'redetermination', and you should mention this in your publication.

Point 4 is if your solution in P21 eventually is wrong, but solving in Pna21 you obtain better structural results. If not however and the data of your collegoues are already publisher, than they are firts!

For checking missed symmetry, even Platon is not needed. The same is possible using checkcif.iucr.org ;)

Our starting material ratio is different. There are some noticeable difference in their bond length and bond angles. The R factor value of our solved structure is 0.03.

Dear Kanrunanidhi,

probably it may different and can be a polymorph too. You take the previous .cif files and open in the Mercury software(http://www.ccdc.cam.ac.uk/Solutions/FreeSoftware/Pages/FreeMercury.aspx) for free, and find out the structural differences in the compound. If you find the difference either in the conformation or packing you can report it as new. Another thing is you record DSC also on this material for polymorphs, the melting may not be unique.

Good luck

The powder XRD generated (simulated) by using mercury software is different from our powder XRD generate from mercury software. The experimental and simulated XRD is exactly match. The melting point is not unique.

Then your result is ultimately different than the reported one... Generate the supporting information like IR, Raman, SS-NMR etc. Probably you can publish your result in high impact journal

Mr. Karunanithi,

The simulated powder XRD by mercury does not provide unambigouse evidencing for polimorphism!!! The cifs of structures obtained under different experiments even solved in one space system (group) provided different patterns.

Please find as attachment the simulated powder XRD of a crystal data collection, which is solved by two Pbca and Pca21 space groups. Same data set provide different in the intensities XRD patterns (data in ref. [a]). Please account that Mercury is utilized.

Furthermore the comparison of these generated patterns solved in 'Pac21' with available cif by other author (TYRAMH according [b]), solving the structure in the same space group give completely different patterns.

Refs (in att.).

(a) B. Ivanova, Journal of Molecular Structure 1016 (2012) 47–54

(b) A. Andersen, Acta Chem. Scand. B 31 (1979) 162.

If you would like to evidenced polymorphism unambigousely, please pay attention on the below papers 1 and 2 where we utilized the IR and Raman spectroscopy of polymorphs, where each of them is evidenced by two-three independent physical methods:

1. B. Ivanova, (2005), Journal of Molecular Structure 738, 233-238.

2. B. Ivanova, M. Spiteller (2012) Quantitative solid-state Raman spectroscopic method for control of fungicides, Analyst, 137, 3355–3364

In this respect you should recrystalized the substance according the condiitions reported by your colleagues and should perform redetermination of the structure in your instrument solving in the orthorhombic space system and when you are sure that you are obtain the so-called 'first polymorphs' than you shiuld perform solid state IR or Raman measurements of both the crystals. If you obtained unambigouse difference, than you may claim for 'new second polymorphs'. But if the vibrational patterns are the same, and the structural data of your colleagues are good than despite of your good solution (R factor 3 %), their structural data are valid.

Please account that the shown in the attachment both solutions of the compound named 'crystal set 1, crystal 1' in both the space groups have comparable R-factors . both smaller than 5 %.

Respected Bojidarka B. Ivanova,

Our structure solved at 294 K. Our cell parameters

a = 13.9844(11) Å

b = 10.7695(9) Å

c = 12.2333(10) Å

Cell volume V = 1842

space group= Pna21

system=orthorhombic

That research group solved at 100 K. Their cell parameters

a=14.0366(10) Å

b=10.7686(7) Å

c=11.8026(8) Å

Cell volume V = 1784

space group=Pna21

system=orthorhombic

Your suggestion please

Mr. Karunanithi,

Currently you provided actually two orthorhombic solutions in same space group Pna21, not as preliminary mentioned monoclinic P21.

Without any additional info, abouth the other experimental parameters for hkl data collection, and complete data in cifs, the structures looks to be the same.

Therefore you reports the same structure and determiination and two different temperatures. If the 'previous' solution is already published that you also would like to publish your data as 'redetermination' especially if your R-factor is higher, but it has not novelty for the structural virewpoint.

If the data collection at low temperature yielded low R-factor, it is also possible that just the quality of the crystals of your colleagues were not so good and/or it have available crystal defects. So that their solution at low-temperature resulted to higher R-factor (eventualy), than your solution which is at higher temperature, but most probably your crystals are with better quality.

1) The powder XRD of the both structures simulated from mercury software is same. The hkl value is match each spectrum.

2) The melting point of the reported structure is 133 degree. For us 104 degree.

3) As per the attached file, DSC shows two endothermic peak (by this result it may be sudopolymorphic)

4) As shown in figure there is some changes in hydrogen bonding.

5) The R-factor of the reported structure is 4.43% for our structure 3%

6) Cell volume for our structure 1842.4 for reported 1784.02

7)Reflections collected for our structure 16793

Hydrogen bonding details

For the clarity.. record TGA on this material so that you can get what material it is. I mean, is it any pseudo polymorph or enantiotropic polymorphic system you get the information after recording TGA on this material perfectly.

What do you think Bojidarka B. Ivanova ?

Dear U B Rao Khandavilli,

Herewith i attach the TGDTA. Your valuable suggestion.

Mr. Khandavilli,

I already send an E-mail to Mr. Karunanithi because of he addressed to me also via the RG post, that without to be recognized with the datacollection files and the solution, for such dispustable question it is not possible to conclude only from one cif-file. Even we are not sure that the new solution in Pca21 is the optimal one. From the available data only, Mr. Karunanithi has not any new polimorphs. Each new solution provide perturbations in the hydrogen bonding parameters as well, therefore these differences are not also meaningfull.

If efentually Mr. Karunanithi, could provide support by independent Raman or IR data which have significantly different patterns, than his statement would be possible. But only from the available data under discussion, his data only confi´rms my opinion, that just fisrtly the structure was solved in lower monoclinic P21 space group and system.

Just a quick comment to add to this discussion. The data you collected at room temperature will not be exactly the same as those reported at 100 K due to thermal expansion of the unit cell. Your cell shows slightly unusual expansion upon warming but this may be linked to the structure (i.e. there is a net volume expansion but some cell parameters shrink and others expand). The overall volume change does not seem unreasonable for a change of nearly 200 K. You should check IR/Raman or DSC for changes in melting point between your sample and the literature as discussed above. If there is no significant change in these data then I'd attribute the difference to the change in temperature. If you want to be sure you should recollect your data at or close to 100 K. If you have access to a VT unit then you can monitor the structure as a function of temperature - the contraction of unit cell parameters on warming is not so common and would be interesting to examine.

In IR spectrum there is one prominent peak at 3221 (NH2 symmetric stretching mode) is missing in our spectrum. DSC they mentioned that the melting point of the material is 133 but for our product the material melts at 104. herewith i attach the DSC and TGDTA for your consideration ... your valuable suggestion please

Mr. Karunanithi, can you provide the IR-spectra of both so-called polymorphs for which you claimed, that you have novellty?. This information which you provided does not reprtesentative.

The attached DSC-data are practically with the same profile of the patterns. Year you have really a diffference of the position of the minimum of the pattern, but such changes may be a result of perturbation of the hydrogen bonding interactions with the temperature. DSC on this respect is a sensible method.

Suche phenomenon we already have in the following paper, where we correlated the single X-ray data, IR-data and DSC-ones:

Synthesis, spectroscopic, thermal and structural elucidation of 5-amino-2-methoxypyridine ester amide of squaric acid ethyl ester: A new material with an infinite pseudo-layered structure and manifested NLO application, Journal of Molecular Structure, 875, 2008, 372-381, Tsonko Kolev, Bojidarka B. Koleva, Tony Spassov, Emilya Cherneva, Michael Spiteller, Heike Mayer-Figge, William S. Sheldrick

As mentioned above this can very simply be explained by anisotropic thermal expansion.if you measure at a few more temperatures you should be able to the thermal expansion coefficient. It is not unusual that some lattice parameters decrease with temp due to anisotropy but the volume of the cellshould increase as youve seen unless you have an exotic material with negative thermal expansion like Silicon.