A forum for discussing recent developments in crystal engineering and supramolecular chemistry.

• Gasidit Panomsuwan

  Can we apply "model of mosaic crystal" and "Williamson-Hall" plot for the heterostructure with small lattice mismatch?

  If we want to determine the characteristic values (lateral and vertical coherence length) and the degree of mosaicity (tilt and twist angles) of the heteroepitaxial films having a small latticeIf we want to determine the characteristic values (lateral and vertical coherence length) and the degree of mosaicity (tilt and twist angles) of the heteroepitaxial films having a small lattice mismatch; for example, SrTiO3/LaAlO3, BaTiO3/SrTiO3; can we use the analysis of line-broadening HRXRD with Williamson-Hall plot to determine these values?

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  • 
    Constantin Gheorghies replied

    If the heterostructure has a typical "structure" having typical XRD spectrum, then can be used the invoked method.

    11 days ago
• Vladimir Uvarov

  Is it possible to recognise the left and right NaClO3 crystals using conventional powder XRD method?

  NaClO3 has cubic structure (P213 (n.198) space group). NaClO3 crystals can possess the left or right symmetry (phenomenon of chirality)

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  • 
    Taghi Salemnoush replied

    Dear Vladimir I think the key ways resolving this matter are indirectly hinted into the basic differences that exist between single crystal x-ray diffraction and powder XRD method and trying toDear Vladimir I think the key ways resolving this matter are indirectly hinted into the basic differences that exist between single crystal x-ray diffraction and powder XRD method and trying to track this differences could be useful to tackle this problem by using just a conventional powder XRD . apparently , the HKL data collected by a typical single crystal x-ray diffraction and the phase changing occurred when using enantiomers at a same HKL point could be a clue to convey that to those measured when using X-rd Powder. i simply mean that you could measure the same Xrd intensities as a feed into a FT derivative equation in order to assess its phase change in order to solve the origin of the phase of relevant radiation .

    12 days ago
• Gasidit Panomsuwan

  Is there any specific epitaxial growth relationship between two c-axis oriented films?

  We fabraicate Au/BTO/STO/p-Si(001) MFIS structure. The BTO and the STO films were highly c-axis orientation as investigated by XRD (2q-w) and pole figure analysis. This indicates that lattice planesWe fabraicate Au/BTO/STO/p-Si(001) MFIS structure. The BTO and the STO films were highly c-axis orientation as investigated by XRD (2q-w) and pole figure analysis. This indicates that lattice planes of both films are well aligned and random in a out-of-plane and an in-plane direction, respectively. However, the relationship of lattice planes in a in-plane direction of the STO and BTO films are unclear. Is there specific epitaxial relatationship between these two films?

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    Gasidit Panomsuwan replied

    Thank you very much Elisabeth and Graziella for the nice suggestions. Gasidit

    12 days ago
• Inigo Valan

  About elongation along c-axis

  Firstly, is the c-axis the axis along the lattice parameter c? Secondly, how can I visualize the c-axis elongation? Do I have to worry about disturbing the crystal symmetry or will the cubic boxesFirstly, is the c-axis the axis along the lattice parameter c? Secondly, how can I visualize the c-axis elongation? Do I have to worry about disturbing the crystal symmetry or will the cubic boxes be placed one above other in the c- axis direction?

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  • 
    Catherine Rice replied

    Texture refers to a situation for a polycrystalline material where the orientation of the grains is not random, but rather there is a preferential orientation to some extent. Generally when speakingTexture refers to a situation for a polycrystalline material where the orientation of the grains is not random, but rather there is a preferential orientation to some extent. Generally when speaking about a thin film, a 100 texture would mean that the 100 direction of the crystallites in the film is mostly perpendicular to the plane of the film, although the other axes of the crystallites could be mostly random. As a simple example, NaCl (table salt) is cubic and the grains tend to have a cubic habit. If you were to scatter NaCl grains on a flat surface, the grains would tend to orient with the a axis perpendicular to the surface - which would be like a 100 texture - but otherwise the grains would be random (not lined up).

    16 days ago
• Charles Kanakam

  I am trying to grow a single crystal for XRD studies, by slow evaporation technique. The compounds being Benzoin and benzil by using several solvents and solvent mixtures, I am getting only smallI am trying to grow a single crystal for XRD studies, by slow evaporation technique. The compounds being Benzoin and benzil by using several solvents and solvent mixtures, I am getting only small needles or thin flakes when I want to grow a bigger crystal. Can any one suggest a suitable method, solvent, or solvent mixtures?

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  • 
    Catherine Rice replied

    As for growing improved crystals, it is best to understand that whatever method you use, go slowly; and whatever vessel you use for crystallization should be as clean as possible, with no dust orAs for growing improved crystals, it is best to understand that whatever method you use, go slowly; and whatever vessel you use for crystallization should be as clean as possible, with no dust or particles to serve as nucleation sites. If slow evaporation is not working well, you might try layering: dissolve the material in one solvent and place the solution in a clean tube-like vessel (longer than it is wide); choose another solvent that the material is less soluble in or insoluble in, that is of lower density. Carefully layer some of the second solvent on top of the solution in the tube, so that it floats on top. Carefully stopper the tube (to avoid evaporation) and leave it in a place where it will be undisturbed, with low vibration. As the two solvents diffuse into each other, crystals should form near the interface.

    17 days ago
• Zubair Iqbal

  as we find crystal diameter from FWHM, as 22nm so where we represent this....

  were calculated with diameter (D) about 30nm, 29nm, 27nm and 29nm respectively from the FWHM of XRD pattern. but i dont know where i represent this how to show this in reality orwere calculated with diameter (D) about 30nm, 29nm, 27nm and 29nm respectively from the FWHM of XRD pattern. but i dont know where i represent this how to show this in reality or imagination........so plz help........

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  • 
    Paul Bowen replied

    Fron XRD line broadening it is in fact a mean cyrstallite size - representative of the coherent crystal size in a polycrystalline powder - see the following web pageFron XRD line broadening it is in fact a mean cyrstallite size - representative of the coherent crystal size in a polycrystalline powder - see the following web page (http://ltp.epfl.ch/page-35598-en.html) and pdf document under protocols - Mean crystallite size by X-ray powder diffraction line broadening (XRD) English

    19 days ago
• Vijiyalakshmi Indhirani

  How to synthesize organic crystals?

  How to synthesize organic crystals? help me out by giving some basic idea regarding organic crystal synthesis

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  • 
    Vijiyalakshmi Indhirani replied

    Thank you sir.i need basic idea about organic crystal synthesis.

    23 days ago
• Nagapradeep Nidamanuri

  [eta],[mu] notations in metal-carboxylate coordinations?

  If one metal is coordinated to one of the carboxylate oxygens(in ligand), what is its representation using [eta] and [mu]? If one metal is coordinated to both carboxylate oxygens, what is itsIf one metal is coordinated to one of the carboxylate oxygens(in ligand), what is its representation using [eta] and [mu]? If one metal is coordinated to both carboxylate oxygens, what is its representation using [eta] and [mu]? If possible please explain me how you decided them.

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  • 
    Nagapradeep Nidamanuri replied

    Thanks to you for your valuable replies

    Apr 11, 2012
• Gang Xu

  Is that possible, a metal-organic framework without pore but can lose and uptake its lattice water reversibly?

  Mof

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  • 
    Gang Xu replied

    Thank you

    Mar 22, 2012
• Nagapradeep Nidamanuri

  I would like to remove either protons of water or whole water molecule attached to Zn metal in a crystal.

  Please suggest any pathways other than heating. During heating, complex is decomposing and adding ammonia is not fulfilling the purpose either. On adding alkaline hydroxide solutions immediatelyPlease suggest any pathways other than heating. During heating, complex is decomposing and adding ammonia is not fulfilling the purpose either. On adding alkaline hydroxide solutions immediately insoluble zinc hydroxide is precipitating.

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  • 
    Pradip S Pachfule replied

    If you want to remove the co-ordinated water molecules from the crystals having Zn metal center, you immerse the crystals of it into the dry (99.99%) low boiling solvents like CCCl3, DCM, MethanolIf you want to remove the co-ordinated water molecules from the crystals having Zn metal center, you immerse the crystals of it into the dry (99.99%) low boiling solvents like CCCl3, DCM, Methanol either alone or mixture of them. In first 12 hrs change the solvent after each 4 hrs and then subsequently add new batch. Immerse crystals for 3 days by changing the solvent for each 12 hrs and then dry it under dry conditions. Take that crystals and evacuate under dynamic vacuum at RT for 12 hrs and then at elevated temperature (above 100 oC) for 24 hrs. For further information please refer papers from Dr. O. M. Yaghi who works on MOFs, whee they have exchanged the solvents several reports.

    Mar 16, 2012
• Navid Amini

  What is "Transcrystallinity" ?

  The transcrystalline layer has other properties compared to the spherulitic form, in the case of PP the transcrystalline layer possesses higher rigidity and lower deformability, which leads toThe transcrystalline layer has other properties compared to the spherulitic form, in the case of PP the transcrystalline layer possesses higher rigidity and lower deformability, which leads to earlier crack initiation and crack propagation but i cannot find anything that explains what is Transcrystallinity.

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    Alexander Simakin replied

    I agree with Kavyashree Manjunath. In technological literature transcrystallinity is introduced as a term describing overgwoth of fibres by the smaller whiskers or fibres of the crystallized matrixI agree with Kavyashree Manjunath. In technological literature transcrystallinity is introduced as a term describing overgwoth of fibres by the smaller whiskers or fibres of the crystallized matrix amorphous material. This transitional zone binds composite and makes it stiffer.

    Mar 14, 2012
• David Stephen

  I am using MOLPAK, FLEXCRYST for predicting purpose. Which package achieves the best minimum and reliable lattice energy?

  I am using MOLPAK, FLEXCRYST for predicting purpose. Which package achieves the best minimum and reliable lattice energy? Also which one has superior potential data. In molpak, prediction isI am using MOLPAK, FLEXCRYST for predicting purpose. Which package achieves the best minimum and reliable lattice energy? Also which one has superior potential data. In molpak, prediction is possible for rigid and small molecules, also flexcryst have too limitations of its own. I tried DMACRYS too.

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  • 
    Tejender Thakur replied

    Please go through recent CSP blind test paper appeared in dec 2011

    Mar 12, 2012
• Nagapradeep Nidamanuri

  Metallic bonding in Potassium?

  Can any one provide me the details of K.....K metallic bonding?

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  • 
    Robert A Jackson replied

    In the metal, the bonding can be explained by the classical model where the K cations are surrounded by a 'sea' of valence electrons, which act as a 'glue' to hold the structure together. I don'tIn the metal, the bonding can be explained by the classical model where the K cations are surrounded by a 'sea' of valence electrons, which act as a 'glue' to hold the structure together. I don't know how this translates to metal-metal bonding in molecular systems.

    Mar 12, 2012
• David Stephen

  XRD training

  Is any universities in India offers XDR [single crystal] training for researchers? if so, kindly mention few

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  • 
    Mohamed Ismail replied

    Only I've mentioned that as an example for chart analysis, thermogravometric anlaysis TGA, thanks for your comment

    Mar 9, 2012
• Ashish Bohre

  Is any universities or Lab in India offering training of operating XRD, SEM, TEM etc for researchers? if so, kindly mention a few.

  Instrumentation training

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  • 
    Dr. S.V. Ramanaiah replied

    You will contact to Indian Institute of Chemical Technology (IICT), CSIR Lab in Hyderabad, Andhra Pradesh.

    Mar 9, 2012