ZnO nanoflowers were synthesized by the hydrothermal process at an optimized growth temperature of 200 • C and a growth/reaction time of 3 h. As-prepared ZnO nanoflowers were characterized by x-ray diffraction, scanning electron microscopy, UV-visible and Raman spectroscopy. X-ray diffraction and Raman studies reveal that the as-synthesized flower-like ZnO nanostructures are highly crystalline with a hexagonal wurtzite phase preferentially oriented along the (1 0 1 1) plane. The average length (234-347 nm) and diameter (77-106 nm) of the nanorods constituting the flower-like structure are estimated using scanning electron microscopy studies. The band gap of ZnO nanoflowers is estimated as 3.23 eV, the lowering of band gap is attributed to the flower-like surface morphology and microstructure of ZnO. Room temperature photoluminescence spectrum shows a strong UV emission peak at 392 nm, with a suppressed visible emission related to the defect states, indicating the defect free formation of ZnO nanoflowers that can be potentially used for UV light-emitting devices. The suppressed Raman bands at 541 and 583 cm −1 related to defect states in ZnO confirms that the ZnO nanoflowers here obtained have a reduced presence of defects.

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The Raman and FTIR spectra of three metal guanidinium sulfates, [C(NH 2 ) 3 ] 2 M II (H 2 O) 4 (SO 4 ) 2 , (M II = Mn, Cd and VO), are recorded. The observed spectral bands are assigned in terms of the fundamental modes of vibration of the guanidinium ions, sulfate groups and water molecules. The appearance of the sulfate tetrahedra's n 1 and n 2 modes in the IR spectra and the partial lifting of the n 4 mode in the Raman spectra indicate the distortion of the SO 4 2− tetrahedra in the structure, so that its symmetry is lowered from T d to C 1 . The geometry of the sulfate group in guanidinium vanadyl sulfate does not deviate much from that of the average sulfate group. The distortion of the SO 4 tetrahedra is stronger in GuCds than in GuMnS. The CN 3 group in the guanidinium ion is planar (D 3h point group) in GuCdS and GuMnS, whereas it is lowered in the vanadyl compound. Furthermore, the spectral analyses show the presence of weak hydrogen bonds in the structures.

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Urinary stones resected from urinary bladders of patients hailing from Kollam district of Kerala State, India were analyzed by SEM, XRD and by thermal analysis techniques. The analytical results indicate that, stones have different composition, i.e., calcium phosphate, calcium phosphate hydroxide and sodium calcium carbonate. Infrared spectral studies also reveal the presence of phosphates or carbonates in these samples. Further, IR spectral investigations have revealed that amorphous carbonated species are occupied in PO(4) sites in calcium phosphate type stone and OH sites in calcium phosphate hydroxide sample. Thermal studies of these samples also reveal that, carbon dioxide is released from carbonated samples upon heating which is related to amount of carbon content and bond strength. Crystals with defects and irregular morphology are grown inside the urinary bladder due to variation in crystal growth conditions.