freakJoe

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  1. Second Pauling’s Rule

    I have problem with those tasks, i was reading about rule, but still have no idea what to do... 1) FeTiO3 (mineral Ilmenite) possesses the corundum structure (remember our discussion in the class) – an hcp array of oxides with cations filling 2/3 of octahedral holes. Use the bond valence rules (Second Pauling’s Rule) to decide which oxidation states are present: Fe(II) Ti(IV) or Fe(III) Ti(III). Bond Distances (dexp, Å) Tabulated reference values Constants FeO = 3×2.07 and 3×2.20 R0(FeO) = 1.795 Å b = 0.30 TiO = 3×1.88 and 3×2.09 R0(TiO) = 1.815 Å b = 0.37 Check for oxygen valence (what is the coordination number of O?): each oxygen is bound to Fe and Ti with both bond distances.) 2) CaWO4 has the scheelite structure where the W6+ ions are tetrahedrally coordinated. Use the bond valence rules (Second Pauling’s Rule) to decide if the WO4 tetrahedra share corners, i.e. oxygens are bridging, or the WO4 tetrahedra are isolated, i.e. oxygens are terminal. Show your bond strength calculation.
  2. silver salt solubility!

    What is the solubility of silver salt of the formula RCOOAg (RCOO=phenylbutyrate, DMF, MeOH, water?)
  3. hi! i have some strange by-product, intermediate, or something... i prepared inorganic complex, and it is contaminated ith something (have problems with purification), when i measure platinum NMR, i can observe signal of my product (which should be yellow), but it is yellowish and white (or white-beige). How could i determine, what is inside, beside my product? could Electrospray measurement help me (ESI-MS)? as far as i know, it can tell you if you have some desired compound structure, but what if it is a mixture? is there any technique to analise what is my product?
  4. titration NMR

    Hello! i will use NMR spectroscopy to determine host-guest binding, and i would like to kindly ask you, what technique is the best to perform NMR titrations!! I probably should prepare solution of guest, and add in portions cavitand into it (also as solution, in the same solvent, e.g. deuterated water)... is it reasonable to prepare mixture of guest with cavitand every time again? like preparation of host-guest, so i: take some part of solution nr 1 (guest solution, prepared for 10 trials for different ration, which volume is constant), add some part of solution nr 2 (cavitand solution, prepared for several trials, which volume changes - 0.5 eq, 1 eq, 1.5 eq with respect to guest), at the end add volume of deuterated solvent to have constant volume of mixture in NMR tube. Would it be right?
  5. NMR titration experiments

    Hello! i will use NMR spectroscopy to determine host-guest binding, and i would like to kindly ask you, what technique is the best to perform NMR titrations!! I probably should prepare solution of guest, and add in portions cavitand into it (also as solution, in the same solvent, e.g. deuterated water)... is it reasonable to prepare mixture of guest with cavitand every time again? like preparation of host-guest, so i: take some part of solution nr 1 (guest solution, prepared for 10 trials for different ration, which volume is constant), add some part of solution nr 2 (cavitand solution, prepared for several trials, which volume changes - 0.5 eq, 1 eq, 1.5 eq with respect to guest), at the end add volume of deuterated solvent to have constant volume of mixture in NMR tube. Would it be right?
  6. trans effect

    when we have for example KPtCl3(NH3) complex, the Pt-N bond is probably more short bond that Pt-Cl... what can i say about them? should it influence the bond which is in trans position to NH3 substutuent? shouldnt it be affected by it, e.g. become weaker? what about orbitals? some polarization? when you have KPtCl3(NH3) molecule, and you add next 1 eq of NH3 to it, it will substute the chloride which is in cis position to NH3 which is aready in molecule, right? becaus NH3 has weaker trans effect than Cl- so it cant put in trans position to itself.
  7. Basicity

    no solvent and water?
  8. Basicity

    It is a part of theoretical investigation... computational chemistry... and i would like to compare calculation results with some theories. I am not sure if i am correct, but i was thinking about the nature of the group attached to NH2. Is it possible, that thanks to -CH3 substituent, which push electrones towards N atom, it makes the molecule more basic? It would tend to accept extra proton more then for example NH2OH, where -OH group withdraw the electrons...?
  9. Basicity

    Which of these molecules is the most basic? NH3, NH2CH3, NH2NH2 or NH2OH?
  10. what is the relationship between the geometry or energy difference between orbitals and chemical shift? Like, for octahedral Pt(IV) is +800, for square planar(II) -2000...
  11. AgI and DMF

    So for water is the same i guess... When i want to substitute chloride ligands (e.g. reaction of chloride with some silver salt), it is better to use iodide instead of chloride, because of good separation (reaction is in water, the product is soluble in water) and iodide has a "high affinity" to silver?
  12. AgI and DMF

    It is not soluble in DMF, right? neither AgCl
  13. preparation of phenyl anhydride

    phenylacetic acid
  14. how to prepare it in a very simple way, starting from phenyl acid? i would like to avoid hard to remove contaminations and use only cheap chemicals... is it good idea to convert acid into salt, and react this salt with acid?
  15. Fern

    Hi, how it is with fern at home? my mum already had lot of them but they are usually dying after about half year... i had one as well, and no matter if i water it a lot, or very rarely, after some time its leaves are getting brown and it is dry... even if ground is wet... i tried to optimize conditions, but why is that? how to water it and keep it in a good condition for a long time? Thanks!