Pure Ammonium Dihydrogen Phosphate Research Articles

Structural, spectroscopic, optical, dielectric and mechanical study of pure and l-Proline doped ammonium dihydrogen phosphate single crystals

Single crystals of pure and l-Proline (LP) C5H9NO2 doped ammonium dihydrogen phosphate (ADP) (NH4) H2PO4 were grown by slow evaporation solution technique (SEST) at ambient conditions. Powder X-ray diffraction (PXRD) analysis was carried out to confirm the crystal structure and no additional phase was observed due to doping except a systematic variation in peak intensities. FT-Raman analysis also confirms that there is no additional phase formation due to doping. Fourier transform infrared spectral analysis was done to examine the presence of various functional groups in the grown crystals. UV–VIS–NIR spectroscopic analysis was carried out to see the change in optical transparency of pure ADP and crystals due to LP with different doping concentrations. The high-resolution X-ray diffraction (HRXRD) analysis was carried out to examine the crystalline perfection and observed reasonable changes with LP doping. Second harmonic generation (SHG) efficiency measurement was done to examine the enhancement in the nonlinear optical characteristics of the grown crystals. The dielectric behavior of the samples shows that the dielectric constant decreased with increase the value of frequency. The effect of LP dopant on crystal morphology, mechanical properties of ADP has also been presented in this paper. The above studies reveal the effect of incorporation of LP into the lattice of ADP crystals.

Effect of Hippuric Acid on the Growth, Structural and Optical Properties of Non Linear Optical Crystals

Non-linear optical potassium dihydrogen phosphate (KDP) and ammonium dihydrogen phosphate (ADP) single crystals with 1 mol% of hippuric acid dopant were grown from aqueous solution by employing slow evaporation technique. With appropriate dopants, the KDP and ADP crystals exhibit several desirable properties. Crystallinity of the grown crystals was studied by powder XRD analysis. The bonding structure and molecular associations were analyzed by FTIR spectroscopy. It also confirms the functional groups present in the grown crystals. UV-Vis-NIR spectral analysis was carried out to study the optical characteristics of the crystals which reveal that the cutoff wavelength for both hippuric acid doped KDP and ADP crystals is around 300 nm. Second harmonic generation (SHG) test adopting the Kurtz Perry technique revealed that the SHG efficiency has increased due to doping when compared with pure KDP and ADP crystals.

Effect of EDTA on the growth kinetics, structural, optical and mechanical properties of ADP crystal

The pure ammonium dihydrogen phosphate (ADP) and ethylenediamine tetra acetic acid (EDTA) added ADP crystals were grown by isothermal evaporation method. The solubility of ADP was determined for five different temperatures. Metastable zone width of aqueous solutions of ADP saturated at different temperatures was determined by nucleation method in pure form and adding with 0.5 mol.% EDTA. The induction period τ was measured and experiments were performed at selected degrees of supersaturation (C/C*) and the critical nucleation parameters like interfacial energy (σ), energy of formation of the critical nucleus (ΔG*) were calculated based on the classical theory of nucleation. The grown crystals have been subjected to study the structural, optical and mechanical properties. FTIR analysis has been carried out to characterize the grown crystals. The transmission spectra from (100) planes of the grown crystals show that the transmission increases from 55.86 to 83.23% due to addition of EDTA in the visible region and band gap was found to increase from 1.31 to 1.41 eV. The microhardness test was carried out on (100) plane. The load dependent hardness and work hardening coefficient were measured.

Effect of s-, p-, d-, and f-block elements on the structure and properties of ammonium dihydrogen phosphate crystals

The influence of the s-, p-, d-, and f-block elements (Cs, Sb, Pd, and Ce) doping on the properties of ammonium dihydrogen phosphate (ADP) crystals has been described. Incorporation of small quantity of dopants into the crystalline matrix is well confirmed by energy dispersive X-ray spectroscopy (EDS) and inductively coupled plasma (ICP) techniques. The reduction in the intensity observed in powder X-ray diffraction (XRD) of doped specimens and slight shifts in vibrational frequencies confirm the lattice stress. Surface morphological changes due to doping of metals are observed by scanning electron microscopy (SEM). The differential scanning calorimetry (DSC) curves show only a slight variation in endothermic peak temperatures. The sharpness of the DSC peaks shows the good degree of crystallinity of the material. The cell parameters have been determined using single crystal XRD analysis of pure ADP and ADP:Cs/ADP:Sb/ADP:Pd/ADP:Ce specimens. The influence of metals on the second harmonic generation (SHG) efficiency is also investigated.

Thiourea-doped ammonium dihydrogen phosphate: A single crystal neutron diffraction investigation

Thiourea-doped ammonium dihydrogen phosphate (TADP) exhibits nonlinear optical property and the second harmonic generation efficiency of these crystals is three times that of pure ammonium dihydrogen phosphate (ADP) crystal. In this context, the study of structural distortion in the thiourea-doped ADP crystal is significant, hence single neutron diffraction investigations were undertaken. The final R-factors are: R[F2 > 2σ(F2)] = 0.11, Goodness of fit(S) = 1.15. Though the dopant could not be located from the difference Fourier map, the cell parameters (a = b = 7.531(3) A, c = 7.544(5) A) were found to be significantly greater than that of pure ADP at RT (a = b = 7.502(1) A, c = 7.546(1) A). This indicates that the dopant concentration in the crystals is small but enough to bring changes in the overall average structure.

Structural distortion in thiourea-mixed ADP crystals

Single crystals of ammonium dihydrogen phosphate (ADP) mixed with different mole concentrations of thiourea were grown using slow evaporation solution technique at 30°C. In order to study the effect of mixing thiourea on the structural characteristics of ADP, X-ray diffraction studies were carried out on the crystals using Shimadzu X-ray diffractometer with Cu Kα radiation. X-ray study revealed that the structures of the thiourea-mixed ADP are slightly distorted compared to the pure ADP crystal structure. Inclusion of thiourea enhances the growth of (1¯ 0 0) plane of the ADP crystal. Thiourea-mixed ADP crystals were found to have maximum inclusion, as the thiourea concentration was 10mol%.

Mutual solubility and metastable zone width of NH 4H 2PO 4KH 2PO 4 mixed solutions and growth of mixed crystals

Mutual solubility of ammonium dihydrogen phosphate (ADP) and potassium dihydrogen phosphate (KDP) has been determined for the full series of composition at 35°C. Stability of the mixed saturated solutions with different compositions has been assessed by measuring the metastable zone width by a nucleation method. Mixed crystals of size 15 × 15 × 75 mm 3 have been grown from ADP or KDP rich solutions on pure ADP and KDP seeds by a slow cooling method.