Akella Radha

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Amorphous calcium carbonate (ACC) is a metastable phase often observed during low temperature inorganic synthesis and biomineralization. ACC transforms with aging or heating into a less hydrated form, and with time crystallizes to calcite or aragonite. The energetics of transformation and crystallization of synthetic and biogenic (extracted from California(More)
We demonstrate that allenes, chiral 1,2-dienes, appended with basic functionality can serve as ligands for transition metals. We describe an allene-containing bisphosphine that, when coordinated to Rh(I), promotes the asymmetric addition of arylboronic acids to α-keto esters with high enantioselectivity. Solution and solid-state structural analysis reveals(More)
The layered double hydroxides (LDHs) of Co with trivalent cations decompose irreversibly to yield oxides with the spinel structure. Spinel formation is aided by the oxidation of Co(II) to Co(III) in the ambient atmosphere. When the decomposition is carried out under N2, the oxidation of Co(II) is suppressed, and the resulting oxide has the rock salt(More)
The hydrotalcite-like layered double hydroxide (LDH) of Mg with Al shows dramatic changes in the peaks arising from the (h0l)/(0kl) family of reflections in its powder X-ray diffraction pattern during thermal treatment. DIFFaX simulations show that these changes arise due to the transformation of the disordered 3R1 polytype into the 1H polytype on(More)
The layered double hydroxide of Mg with Al decomposes below 600 degrees C with the loss of nearly 48% mass, resulting in the formation of an oxide residue having the rock salt structure and nanoparticulate morphology. However, this product reconstructs back into the parent LDH, owing to its compositional and morphological metastability. The oxide can be(More)
Carbonate and chloride ions mediate an ordered stacking of metal hydroxide slabs to yield ordered layered double hydroxides (LDHs) of Zn with Al, by virtue of their ability to occupy crystallographically well-defined interlayer sites. Other anions such as ClO(4)- (T(d)), BrO(3)- (C(3v)), and NO(3)- (coordination symmetry C(2v)) whose symmetry does not match(More)
The hydrothermal reactions of calcium, strontium, and barium with l-, meso-, and d,l-tartaric acid were examined from room temperature to 220 degrees C. We report the synthesis of 13 new phases and crystal structures of 11 alkaline earth tartrates, including an unusual I(3)O(0) framework, [Ba(d,l-Tar)] (Tar = C(4)H(4)O(6)(2-)), with 3-D inorganic(More)
A combined approach using the Rietveld technique of structure refinement and DIFFaX simulations of the powder patterns enables us to not only arrive at the complete structure of the layered double hydroxides (LDHs), but also classify and quantify the nature of structural disorder. Hydrolysis of urea dissolved in mixed-metal salt solutions containing a(More)
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