The growth of pure Gd-and mixed Gd-Ba-molybdate crystals, bearing the stoichiometric composition Gd 2 Mo 7 O 24 ‚xH 2 O and Gd 2 Ba 24 Mo 42 O 153 , is achieved by the gel technique, using the system RCl 3 -(NH 4 ) 6 Mo 7 O 24 -NH 4 NO 3 -HNO 3 -Na 2 SiO 3 (where R ) Gd, Gd:Ba). Addition of Ba in the lattice of pure Gd-heptamolybdate influences the morphological developments of grown crystals. While pure Gd-heptamolybdate assumes a spherulitic morphology under all conditions of growth, the addition of Ba modifies the morphology of mixed crystals drastically and develops them as well-facetted pyramidal twinned crystals. The mixed crystals do not carry any water of hydration and are thermally more stable as compared to pure Gd-heptamolybdate carrying water of hydration.

Growth of pure-, sodium-and lithium-doped potassium hydrogen tartrate single crystals by gel technique is reported. Growth conditions conducive for the growth of single crystals are worked out. The crystals are characterized by using powder XRD, SEM, FTIR, AES, EDAX, CH analysis and thermoanalytical techniques. The stoichiometric composition for the grown crystals are established asDoping of sodium and lithium in the pure potassium hydrogen tartrate single crystals is found to influence the size, perfection, morphology, crystal structure and the thermal stability of crystals.

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Manganese dioxide oxidation of thioureas in chloroform at room temperature gave the corresponding ureas.