Concentrations Of Ammonium Thiocyanate Research Articles

Effect of ammonium thiocyanate (NH4SCN) concentration on the ionic transport in dextran-based polymer electrolyte

Solid polymer electrolytes (SPEs) have been recognized as a preferable alternative to liquid electrolytes for energy storage application. However, low conductivity of SPEs has restricted their application. This issue can be overcome by adding controlled amount of dopant salt to the SPEs. In this work, various concentration of ammonium thiocyanate (NH4SCN) salt was incorporated into dextran using solution cast technique in order to study the effect of NH4SCN on electrical properties, crystallite size, morphology and ionic conductivity. Results from Fourier-transform infrared (FTIR) analysis confirm the coordination of cation of salt at the OH and C-O-C groups of dextran. Deconvolution of the FTIR band between 2015 and 2090 cm−1 was performed to investigate the ion association and dissociation phenomena. It is confirmed that the ion mobility and diffusion are directly proportional to the ionic conductivity. Based on the electrochemical impedance spectroscopy (EIS) result, an optimum ionic conductivity of (3.18 ± 1.19) × 10−4 S cm−1 was achieved with the sample containing 40 wt.% salt concentration. The conductivity result can be clarified by the crystallite size obtained from X-ray diffraction (XRD) analysis and field emission scanning electron microscopy (FESEM) images.

Rapid americium separations from complex matrices using commercially available extraction chromatography resins

A method for rapid separation of americium from complex matrices by use of two commercially available extraction chromatography resins is reported. TRU resin is capable of purifying americium/lanthanides together from Group 1, Group 2 and transition metals. TRU resin tolerated high loadings of iron, aluminium, calcium sodium and potassium. TEVA resin purified americium/lanthanides by elution with ammonium thiocyanate. Decontamination factors > 20,000 were achieved within one working day. The affinity of TEVA resin for americium, curium and lanthanides as a function of ammonium thiocyanate concentration is reported. The possibility of americium/lanthanide separations on LN resin has been explored.

Facile extractive separation studies of uranium(VI) assisted by dicyclohexano-18-crown-6 through green approach

A reliable precise analytical method has been developed for the extraction of uranium(VI) from 1 M ammonium thiocyanate and 1 M acetic acid with 0.001 M dicyclohexano-18-crown-6 in nitrobenzene. Various parameters like ammonium thiocyanate concentration, acetic acid concentration, reagent study, solvent study, strippant study and loading capacity were studied. Uranium(VI) were selectively extracted and separated from diverse ion and ternary mixture. The proposed method was also used for the determination of uranium(VI) from rock and monazite sand sample.

Investigation of blend biopolymer electrolytes based on Dextran-PVA with ammonium thiocyanate

A new polymer electrolytes based on Dextran, poly vinyl alcohol (PVA) with different concentrations of ammonium thiocyanate (NH4SCN) have been prepared by solution casting technique using distilled water as a solvent. The synthesized biopolymer membranes have been characterized by various techniques such as X-ray diffraction (XRD), Fourier transform–infrared spectroscopy (FTIR), differential scanning calorimetric (DSC), AC impedance, linear sweep voltammetry (LSV), and transference number measurement. The increase in amorphous nature of the blend polymer (700 mgDextran:300 mgPVA) with increase in salt concentration is observed in XRD pattern. The complex formation between the blend polymer and salt has been confirmed by FTIR. The glass transition temperature (Tg) of the prepared polymer membranes have been analyzed by DSC. From AC impedance analysis, a maximum ionic conductivity of 8.03 × 10−3 S/cm has been achieved by incorporation of 0.6 M.wt% NH4SCN with blend polymer (700 mgDextran:300 mgPVA). The electrochemical stability of the highest conducting polymer electrolyte 700 mgDextran:300 mgPVA:0.6 M.wt%NH4SCN has been observed as 3.01 V by LSV. From Wagner’s polarization method, transference number has been calculated. The proton battery has been constructed with the highest conducting polymer electrolyte 700 mgDextran:300 mgPVA:0.6 M.wt%NH4SCN. The open-circuit voltage (OCV) has been observed as 1.75 V and the battery performance is studied.

The Effect of Timing of Tetanus-Diphtheria-Acellular Pertussis Vaccine Administration in Pregnancy on the Avidity of Pertussis Antibodies.

Background: Optimal timing of gestational tetanus-diphtheria-acellular pertussis (Tdap) vaccination is not well-defined. No well-established specific anti-pertussis antibody level correlates with protection, suggesting the importance of antibody quality such as avidity. We aimed to determine the effect of timing of vaccination with Tdap in pregnancy on the avidity of cord anti-pertussis toxin (PT) immunoglobulin G (IgG).Methods: Prospective study of newborns in a tertiary hospital (Melbourne, Australia) born to women vaccinated with Tdap in pregnancy. Ammonium thiocyanate was used as a bond-breaking agent to measure the avidity of anti-PT IgG using concentrations between 0.25 M (to measure low avidity antibodies) and 3 M (to measure very high avidity antibodies). Anti-PT IgG levels achieved at each ammonium thiocyanate concentration in cord samples of women vaccinated during 28–32 weeks gestation (WG) vs. 33–36 WG, and women vaccinated 5–12 vs. 1–4 weeks prior to delivery were compared using t-tests.Results: Newborns of women vaccinated with Tdap during 28–32 WG (n = 43) had statistically significant higher concentrations of medium and high avidity anti-PT IgG compared with newborns of women vaccinated during 33–36 WG (n = 47), 11.6 IU/ml (95% CI, 8.8–15.2) IU/ml vs. 6.7 IU/ml (95% CI, 5.2–8.6) and 10.1 IU/ml (95% CI, 7.4–13.8) vs. 5.7 (95% CI, 3.6–8.9) IU/ml (p = 0.007 and p = 0.035), respectively. Newborns of women vaccinated 5–12 weeks before delivery (n = 64) had statistically significant higher concentrations of high and very high avidity anti-PT IgG compared with newborns of women vaccinated within 4 weeks before delivery (n = 25), 10.3 IU/mL (95% CI, 7.9–13.4) vs. 3.3 IU/mL (95% CI, 1.7–6.4), 12.6 IU/mL (95% CI, 9.4–16.9) vs. 4.3 IU/mL (95% CI, 2.2–8.5) (all p < 0.03), respectively.Conclusions: Quantification of levels of anti-PT IgG with different avidities demonstrated that pertussis vaccination 5–12 weeks before delivery was associated with higher anti-PT IgG avidity compared with vaccination within 4 weeks before delivery. Pertussis vaccination during 28–32 WG was associated with higher anti-PT IgG avidity compared with vaccination during 33–36 WG, supporting vaccination at 28–32 over 33–36 WG for optimal protection against pertussis in infancy.

AC impedance studies on proton conducting biopolymer electrolytes based on pectin

Pectin based biopolymer electrolytes are prepared with different concentrations of ammonium thiocyanate by solution casting technique using distilled water as solvent. The amorphous nature and complexation of salt with polymer matrix are confirmed by X-ray diffraction (XRD) and Fourier transform infra-red spectrometer (FTIR) for all the prepared electrolytes. The cole-cole plot gives the maximum ionic conductivity of 4.05 × 10−6 S/cm for 0.08 g (20 mol%) of ammonium thiocyanate doped system. The number of the stoichiometrical charge carriers (n) in the 0.08 g salt doped system is 2.057 × 1021 cm−3 and it has maximum proton conduction as confirmed by transport number studies. The dielectric properties of the prepared proton conducting biopolymer electrolytes are also discussed in this work.

Structural, vibrational, thermal, electrical properties of PVP–PVC blend NH4SCN

Polymer blending is one of the most important methods used to obtain new polymeric materials, and it is a useful technique for designing electrolyte materials with required modifications in the properties, such as electrical, thermal and mechanical. PVP–PVC blend membrane doped with different molar weight percentage of NH4SCN has been prepared by solution casting technique using DMF as solvent. XRD, FTIR, DSC and AC impedance studies have been made for the above membrane. XRD studies reveal the amorphous nature of membrane. A complex formation has been confirmed by FTIR studies. Differential scanning calorimetry shows that the thermal stability and the glass transition temperature decreases with the increase in concentration of ammonium thiocyanate. The maximum proton conductivity of the polymer electrolyte is determined by AC impedance spectroscopy. A maximum conductivity of 4.01 × 10−4 S cm−1 has been observed for the composition of 70PVP:30PVC:0.3 M wt% of NH4SCN. Dielectric and modulus behaviors have been studied for the above membrane and the relaxation frequency (τ) is calculated from the loss tangent spectra (tan δ). The primary proton battery with configuration Zn + ZnSO4·7H2O/70PVP:30PVC:0.3 M wt% NH4SCN/PbO2 + V2O5 are fabricated.

Electrochemical Hydrogen Permeation Tests Under Potentiostatic Hydrogen Charging Conditions Conventionally Used for Hydrogen Embrittlement Study

Electrochemical hydrogen charging is a commonly used method for hydrogen embrittlement study of high strength steels as well as immersion in ammonium thiocyanate solutions. Hydrogen concentration in specimens in wide range, from low hydrogen concentration simulating that caused by atmospheric corrosion to relatively high hydrogen concentration to emphasize the effect of hydrogen on hydrogen embrittlement fracture, can be obtained either by changing hydrogen charging solutions with/without catalyst poisons and by controlling current density and potential applied to specimens. However, in many cases, hydrogen concentration is controlled in a trial-and-error manner. To understand the behavior of hydrogen entry in various hydrogen charging conditions and to obtain guidelines for efficient electrochemical hydrogen charging, electrochemical hydrogen permeation tests were performed in galvanostatic hydrogen charging conditions and the effects of current density and solution were reported in our previous study. In the present study, aiming at the same purpose, potentiostatic hydrogen charging was carried out using varied conditions and the hydrogen entry was monitored by means of electrochemical hydrogen permeation test and the results were compared with that obtained by using galvanostatic hydrogen charging. In the same way of the previous study, 0.5 mm-thick pure Fe sheet specimens set in a Devanathan-Stachurski cell were used in this study. The hydrogen input side of the specimen was potentiostatically polarized in 3 wt% NaCl solutions containing varied concentration of ammonium thiocyanate and a 0.1 M NaOH solution, open to air at room temperature. The Ni-plated hydrogen output side was polarized at 20 mV vs. Hg/HgO in a 0.1 M NaOH solution and the electrochemical hydrogen permeation current density was monitored in various potentiostatic hydrogen charging conditions. Hydrogen permeation current density was increased almost linearly with decrease in hydrogen charging potential. Exceptionally, at relatively high potential region the hydrogen permeation current density was lower than the extrapolation of the line probably because oxygen reduction decreases the efficiency of hydrogen entry. The efficiency of hydrogen entry expressed by the ratio of hydrogen permeation current density to hydrogen charging current density at the applied potential was decreased with decrease in potential accompanied with increase in cathodic current density. The increase in ammonium thiocyanate concentration led to enhancement of hydrogen entry drastically. These results were almost the same as that obtained for galvanostatic hydrogen charging in the previous study, and the relationship between hydrogen charging potential and hydrogen permeation current density of the potentiostatic hydrogen charging was similar to the relationship between potential of hydrogen input side resulted by galvanostatic hydrogen charging and hydrogen permeation current density. The relationship obtained in the present study can be used as guidelines for potentiostatic hydrogen charging. Though it is assumed that potentiostatic and galvanostatic hydrogen charging are similar to each other in principle, stability of hydrogen permeation current density showed some differences. In the presentation, stability of hydrogen permeation current density under the potentiostatic and galvanostatic hydrogen charging will be also discussed.

Electrochemical hydrogen permeation tests under galvanostatic hydrogen charging conditions conventionally used for hydrogen embrittlement study

AbstractElectrochemical hydrogen permeation tests using pure Fe sheet specimens were performed under various galvanostatic hydrogen charging conditions commonly applied to tensile test specimens used for evaluation of hydrogen embrittlement property to obtain a guideline for efficient hydrogen charging method for a wide range of hydrogen content. Aqueous NaCl solutions containing varied concentrations of ammonium thiocyanate and a 0.1-m NaOH solution were used as electrolytes for relatively high and low hydrogen content, respectively. Addition of ammonium thiocyanate changes the mechanism of hydrogen evolution reaction and enhances hydrogen entry. By changing the concentration of ammonium thiocyanate and by changing cathodic current density, a wide range of hydrogen content can be covered. The hydrogen content in an AISI 4135 steel estimated from hydrogen permeation current density obtained for a pure Fe specimen was in good agreement with the hydrogen content experimentally measured by hydrogen thermal desorption analysis for the AISI 4135 steel. The hydrogen permeation current density data in various hydrogen charging conditions can be used as a reference for hydrogen charging of specimens.

Surfactant‐Assisted Dispersive Liquid–Liquid Microextraction for Sensitive Spectrophotometric Determination of Iron in Food and Water Samples and Comparison with Atomic Absorption Spectrometry

AbstractA technique of selective and sensitive surfactant‐assisted dispersive liquid–liquid microextraction combined with spectrophotometry was developed for determination of iron in water and food samples. This method involves the formation of a red‐colored iron‐thiocyanate complex in the presence of cetyltrimethylammonium bromide (CTAB) as cationic surfactant. The use of CTAB assisted in color formation and effective extraction of the complex into the organic solvent through micelle formation prior to spectrophotometric and flame atomic absorption spectrometry measurement. Optimum absorbance and extraction of the iron complex was obtained with concentrations of ammonium thiocyanate, N‐phenylbenzimidoyl thiourea, CTAB and sodium chloride of 0.30 M, 3.0 × 10−3 M, 0.40 × 10−3 M and 1.0 %, respectively. The calibration curve was linear over a range of 20–350 ng mL−1 iron with correlation of estimation (R2) of 0.997. The proposed method was successfully applied to the determination of iron in food (cereal, fruit and vegetable) and water samples.

Dot-ELISA Affinity Test: An Easy, Low-Cost Method to Estimate Binding Activity of Monoclonal Antibodies

Selecting the “right” monoclonal antibody (mAb) for an immunoaffinity-based application can be tricky, as many mAb producers offer a wide range of mAb clones against molecular structures of interest. Since there are significant differences in the quality of mAb clones, and particularly in their binding activity, an easy method for quick and low-cost comparison of various mAb clones was developed. The dot-ELISA affinity test is a simple, versatile and instrumentally no demanding technique, since it requires no expensive equipment (such as an ELISA reader or chemiluminescence/fluorescence imaging system) and can be performed in any biochemical laboratory. This method is based on a previously described dot-ELISA technique that is improved with a chaotropic step using different concentrations of ammonium thiocyanate in the range 0-2 M. In this work, the dot-ELISA affinity test was optimized on Aβ peptide as antigen and anti-Aβ mAb. Such protocol was then applied to a panel of eight anti-EpCAM (epithelial cell adhesion molecule) mAbs which should be subsequently used for preparation of magnetic immunosorbent to capture circulating tumor cells (CTCs).

Extractive Separation of Cadmium(II) using Cyanex 923 from Ammonium Thiocyanate Medium

A selective and effective solvent extraction method has been developed for the separation of cadmium(II) using Cyanex 923 in toluene. Cadmium(II) was quantitatively extracted using 0.1 M Cyanex 923 in toluene from 1.0 M ammonium thiocyanate media. The extracted cadmium(II) was quantitatively stripped with 3.0 M nitric acid from organic phase and determined spectrophotometrically with PAR at 520 nm. The optimum extraction conditions have been evaluated by studying parameters such as ammonium thiocyanate concentration, Cyanex 923 concentration, equilibration time, various diluents, diverse ions, and stripping agents. The selective and sequential separation of cadmium(II) from other cations was achieved in binary as well as multicomponent mixtures. The method was extended for the separation of cadmium from spent nickel-cadmium batteries, some aquatic plants and zinc blende. The reliability of the method is assured by a comparison of the results with those obtained using AAS.

Conduction and thermal properties of a proton conducting polymer electrolyte based on poly (ε-caprolactone)

A proton conducting polymer electrolyte based on poly(ε-caprolactone) (PCL) complexed with different concentrations of ammonium thiocyanate (NH 4SCN) salt has been investigated. The ionic conductivity of the solid polymer electrolyte (SPE) of pure PCL obtained at room temperature is 1.86 × 10 − 11 S cm − 1 . The maximum ionic conductivity achieved in the solution-cast films at room temperature is 1.01 × 10 − 4 S cm − 1 for PCL incorporated with 26 wt.% NH 4SCN. The calculated dielectric constant at selected frequencies follows the same trend as conductivity, concluding an increase in number density of ions with the salt content. DSC thermogram shows that the degree of crystallinity of PCL is reduced as more salt is accommodated in the PCL crystalline phase. The FTIR of asymmetric C≡N stretching mode is deconvoluted into three bands representing free ions, contact ion pairs and ion aggregates to obtain an insight on ion associations. The FTIR results show that the number of free ions become maximum at 26 wt.% NH 4SCN. The correlation between free ions, ion aggregates and conductivity is obvious. The increase in ion dissociation improves conductivity, while the formation of ion aggregates reduces conductivity.

Erratum to: “Statistical Modeling of Electrochemical Reactivation Conditions for Detecting Sensitization to IGC of Austenitic Stainless Steel Type 316L”

The aim of this study was to determine the optimum conditions of the DL EPR test in order to evaluate the highest values of the degree of sensitization (DOS) of a forged austenitic stainless steel type 316L evaluated by the ratio Ir/Ia or Qr/Qa in %. The criteria of sensitization to the IGC corresponds toIr/Ia > 1% and Qr/Qa > 1%. A model using a full factorial design has been established, and the selected factors were the sweep rate (dE/dt), sulphuric acid concentration (H2SO4), ammonium thiocyanate concentration (NH4SCN), and temperature in °C. A first order model is obtained by using a 24 full factorial design. An experimental test carried out using a 24 factorial design indicated that all the factors and their interactions have a positive effect on the response Ir/Ia. Furthermore, the highest value detected ofIr/Ia was found to be 65.6%. On the other hand, a microstructural study based on an optical microscope and a scanning transmission electron microscope (STEM) has been carried out for annealed and aged samples (550°C-80000 h). The profiles of the chromium, nickel, and molybdenum concentration established by X-ray microanalysis in STEM confirm a decrease of the content of these elements leading to the formation of Cr-depleted zones responsible for the sensitization to the IGC.

UV radiation and the reaction between ammonium and thiocyanate under prebiotic chemistry conditions

The reaction between ammonium and thiocyanate under prebiotic chemistry conditions was studied using FT-IR spectroscopy. Ammonium thiocyanate (1.0 10-3 mol L-1) was dissolved in sodium chloride solution (28.57 g L-1) at two different pH values (5.30 and 7.20). FT-IR results showed that it was possible that some compound that resembles dithiooxamides was synthesized when samples of ammonium thiocyanate were exposed to UV radiation under a regular atmosphere, as UV radiation in the presence of oxygen leads to the formation of perchlorate ions (ClO4-) due to the presence of Cl- ions as well. After acid hydrolysis of the samples of ammonium thiocyanate irradiated under a nitrogen atmosphere, yellow and white compounds were obtained, which could not be identified. These results were different from those reported in the literature, where other authors found methionine. However, they used higher concentrations of ammonium thiocyanate and a different type of UV lamp. On the other hand, in the present study, a lower concentration of ammonium thiocyanate was used, which probably resembled more the concentration of ammonium thiocyanate of primitive earth.

Vibrational and impedance spectroscopic study on PVP–NH 4SCN based polymer electrolytes

Polymer electrolytes based on poly ( N-vinyl pyrrolidone) (PVP) and ammonium thiocyanate (NH 4SCN) prepared by solution cast technique have been studied using X-ray diffraction (XRD), Raman and impedance spectroscopic techniques. The XRD and Raman spectra for the electrolytes indicate that the amorphous nature of PVP increases with the increase of the concentration of ammonium thiocyanate. The spectral changes in the Raman bands of the C O and the C N stretching indicate the interaction between the salt and the polymer. The conductivity analysis shows that the 20 mol% ammonium thiocyanate doped polymer electrolyte exhibits high ionic conductivity and it has been found to be 1.7×10 −4 S cm −1, at room temperature. The ionic coordination in the polymeric electrolytes, as determined by Raman spectroscopy, has been discussed in relation to the conductance behavior.

Spectroscopic study for photocatalytic decomposition of organic compounds on titanium dioxide containing sulfur under visible light irradiation

Yellowish S-containing TiO 2 (S–TiO 2) powders were prepared by calcination of a mixture of titanium(III) chloride and ammonium thiocyanate solutions. Three kinds of S–TiO 2 were prepared by varying the concentration of ammonium thiocyanate (0.5, 1 or 13 M). X-ray photoelectron spectroscopy spectra of the S–TiO 2 showed that sulfur atoms existed on the surface of TiO 2 powders. But the peaks assigned to S disappeared after Ar + etching, which means that these atoms were not doped in the bulk of the TiO 2 powders. While UV–visible absorption spectra of S–TiO 2 showed that the absorption edges of these photocatalysts were seen to shift to a longer wavelength (lower band gap energy) than those of undoped rutile TiO 2 prepared and commercial anatase type TiO 2 (ST-01). The S–TiO 2 (1 M) exhibited higher photocatalytic activity than ST-01 for degradation of methylene blue in aqueous solution under visible light irradiation ( λ > 400 nm ). It was also confirmed by IR spectroscopy that acetaldehyde in oxygen under visible light irradiation ( λ > 400 nm ) was decomposed to acetic acid by the S–TiO 2 and ST-01 at the first decomposition step.

Studies on ion transport of some rare earth elements through solvating extractants immobilised on supported liquid membrane

The studies on ion transport of terbium and dysprosium through a porous supported liquid membrane (SLM) containing TOPO (trioctyl phosphine oxide) and TBP (tributyl phosphate) as immobilised carriers have been carried out. The effect of stirring of bulk solutions on permeability coefficient has been investigated. The permeability coefficient increases with increase in pH of source phase from 0–6, and hydrogen ion concentration from 0.01 to 0.1 M of receiving solution. The dependency of permeability coefficient on the carrier concentration has been explored. The effect of ammonium thiocyanate concentration on permeability coefficient has been studied. In order to develop a method for enrichment of rare earth elements, further investigations were carried out by using a hollow fibre membrane extractor. The mechanism of ion transport of terbium and dysprosium in SLM systems has been explained.

Decomposition of Thiocyanates During Electrolysis

The fate of thiocyanate ion during electrolytic silver recovery operations was studied. The experimental conditions for these laboratory tests were chosen to simulate conditions that might be applied in the recovery of silver in the photographic industry. A photographic fixer solution spiked with a one molar concentration of ammonium thiocyanate was electrolyzed in a commercially available rotating cathode silver recovery cell at a current density of 20 mA/cm2. A low concentration of hydrogen cyanide gas (generally <1 ppm)was detected in the headspace of the electrolytic cell during the constant current electrolysis. Analysis of the fixer solution after electrolysis also confirmed the presence of cyanide in the liquid phase.

チオシアン酸アヌモニウム溶液によるニッケルの溶解

This study is a fundamental research for using the rhodan waste solution to remove nickel from nickel alloy scraps. The dissolution of nickel in basic ammonium thiocynate was studied, and its dissolution mechanism was discussed. The results obtained are surmmarized as follows: The dissolution of nickel can be effectively carried out by the blowing oxygen gas with the presence of Cu (II). The largest rate was obtained in the pH range of 9 to 9.5, but the favorable value of pH in the solution is 9, because, it is necessary to suppress the evaporation of NH3. Nickel is scarcely dissolved in the solution of Cu (II) ammine alone, however, the dissolution of nickel is sharply increased by adding of a small amount of SCN-ions to the solution of Cu (II) ammine. And the dissolution rate is considerably higher than that in the solution containing ammonium alone. Nickel is chiefly dissolved as the amine complex Ni (NH3) n2+, and the CuSCN films is formed on the surface of nickel as the nickel is dissolved. However, it can be gradually dissolved with increasing NH3and SCN-ions, and subsequently the dissolution of nickel proceeds. The dissolution rate of nickel increases proportionally with the concentration of ammonium thiocyanate at its lower concentration. The activation energy of dissolution in this region was 68.5 kJ/mol. The rate-determining step is assumed to be the chemical reaction on an anodic site of the surface of nickel. At the higher concentration of ammonium thiocyanate, the dissolution rate of nickel is constant independently of the concentration, but it is proportional to the concentration of Cu (II). The activation energy of dissolution in this region was 16.3 kJ/mol. The rate-determining step is assumed to be the diffusion of Cu (II) on the cathodic site of nickel. The reactions are considered as follows: Ni+2SCN-+2Cu (NH3) 42+=Ni (NH3) n2++2CuSCN (s) + (8-n) NH3CuSCN (s) +SCN-=Cu (SCN) 2-Cu (SCN) 2-+4NH3+H++1/4O2=Cu (NH3) 42++2SCN-+1/2H2OCuSCN (s) +4NH3+H++1/4O2=Cu (NH3) 42++SCN-+1/2H2O