Thiocyanate Research Articles

Guanidinium-Pseudohalide Perovskite Interfaces Enable Surface Reconstruction of Colloidal Quantum Dots for Efficient and Stable Photovoltaics.

Complete surface passivation of colloidal quantum dots (CQDs) and their strong electronic coupling are key factors toward high-performance CQD-based photovoltaics (CQDPVs). Also, the CQD matrices must be protected from oxidative environments, such as ambient air and moisture, to guarantee air-stable operation of the CQDPVs. Herein, we devise a complementary and effective approach to reconstruct the oxidized CQD surface using guanidinium and pseudohalide. Unlike conventional halides, thiocyanate anions provide better surface passivation with effective replacement of surface oxygen species and additional filling of defective sites, whereas guanidinium cations promote the construction of epitaxial perovskite bridges within the CQD matrix and augment electronic coupling. Additionally, we replace a defective 1,2-ethanedithiol-treated CQD hole transport layer (HTL) with robust polymeric HTLs, based on a judicious consideration of the energy level alignment established at the CQD/HTL interface. These efforts collectively result in high-performance and stable CQDPVs with photocurrents over 30 mA cm-2, ∼80% quantum efficiency at excitonic peaks and stable operation under humid and ambient conditions. Elucidation of carrier dynamics further reveals that interfacial recombination associated with band alignment governs both the CQDPV performance and stability.

Synthesis, Characterization and Antimicrobial Activities of mixed Ligand Metals Complexes with Trimethoprim and Potassium Thiocyanate

A new series of Mn (II) and Ni (II) mixed ligands-metal complexes derived from trimethoprim (TMP) and thiocyanate (TC) have been synthesized in aqueous medium and characterized by spectroscopic studies using IR. The coordination of the two ligands towards central metal ions has been proposed in the light of elemental analysis using barium chloride gravimetric method, various colours of metal complexes were obtained ranging from green to light green and found to be soluble in ethanol, butanol, and insoluble in n-hexane, propan-2-ol, and benzene. The following physical parameters were also observed; solubility, melting point and conductivity. The results of the physical and spectroscopic data confirmed that the ligands are chelating agents. The results of spectroscopic studies revealed that TMP acts as a mono-dentate ligand coordinating through the nitrogen of the pyrimidine group and coordination through the nitrogen of the amine group, while in the TC coordination occurred through the sulphur and nitrogen groups because thiocyanate shares its negative charge approximately equally between sulfur and nitrogen. As a consequence, thiocyanate can act as a nucleophile at either sulfur or nitrogen, it is an ambidentate ligand. Antimicrobial activity of the mixed ligands metal complexes and the free ligands were carried out against the bacterial Escherichia coli, Staphylococcus aureus, Klebsiella pneumonia, Pseudomonas aeruginosa, Bacillius subtilis and the fungi; Sclerotinia trifoliorium, Fusarium oxyporium, Stemania paradoxa, Brotrytis cinerea. The mixed ligands metal complexes showed higher activities when compared to the free ligands of TMP but were less active than the free TC ligand. The complexes of Mn (II) showed the highest antimicrobial activity while the Ni (II) complex showed the least activity against the bacterial and fungi organisms. Structure activity relationship showed that Ni (II) complexes containing sulphate ions are more active, while for Mn (II) complexes containing thiocyanate ions showed more enhanced activity than those containing sulphate ions.

Synthesis, crystal structure and thermal properties of bis-(1,3-di-cyclo-hexyl-thio-urea-κS)bis(iso-thiocyanato-κN)cobalt(II).

Crystals of the title compound, [Co(NCS)2(C13H24N2S)2], were obtained by the reaction of Co(NCS)2 with 1,3-di-cyclo-hexyl-thio-urea in ethanol. Its crystal structure consists of discrete complexes that are located on twofold rotation axes, in which the CoII cations are tetra-hedrally coordinated by two terminal N-bonded thio-cyanate anions and two 1,3-di-cyclo-hexyl-thio-urea ligands. These complexes are linked via inter-molecular N-H⋯S and C-H⋯S hydrogen bonding into chains, which elongate in the b-axis direction. These chains are closely packed in a pseudo-hexa-gonal manner. The CN stretching vibration of the thio-cyanate anions located at 2038 cm-1 is in agreement with only terminal bonded anionic ligands linked to metal cations in a tetra-hedral coordination. TG-DTA measurements prove the decomposition of the compound at about 227°C. DSC measurements reveal a small endothermic signal before decomposition at about 174°C, which might correspond to melting.

Ion transport mechanism in anhydrous lithium thiocyanate LiSCN Part I: ionic conductivity and defect chemistry.

This work reports on the ion transport properties and defect chemistry in anhydrous lithium thiocyanate Li(SCN), which is a pseudo-halide Li+ cation conductor. An extensive doping study was conducted, employing magnesium, zinc and cobalt thiocyanate as donor dopants to systematically vary the conductivity and derive a defect model. The investigations are based on impedance measurements and supported by other analytical techniques such as X-ray powder diffraction (XRPD), infrared (IR) spectroscopy, and density functional theory (DFT) calculations. The material was identified as Schottky disordered with lithium vacancies being the majority mobile charge carriers. In the case of Mg2+ as dopant, defect association with lithium vacancies was observed at low temperatures. Despite a comparably low Schottky defect formation enthalpy of (0.6 ± 0.3) eV, the unexpectedly high lithium vacancy migration enthalpy of (0.89 ± 0.08) eV distinguishes Li(SCN) from the chemically related lithium halides. A detailed defect model of Li(SCN) is presented and respective thermodynamic and kinetic data are given. The thiocyanate anion (SCN)- has a significant impact on ion mobility due to its anisotropic structure and bifunctionality in forming both Li-N and Li-S bonds. More details about the impact on ion dynamics at local and global scale, and on the defect chemical analysis of the premelting regime at high temperatures are given in separate publications (Part II and Part III).

An investigation into the impact of introduced thiocyanate anions on the trinuclear Co(II) salamo-based complex

The reaction of Co(OAc)2·4H2O with multisite coordinated salamo-based ligand H2L containing six coordinating sites in presence of co-ligand NCS- anions afforded successfully a trinuclear Co(II) complex [Co3(L)2(NCS)2]. The trinuclear Co(II) complex has been characterized by elemental analyses, UV-visible, Fourier transform infrared spectroscopic methods and DFT calculation. In addition, the structure of the Co(II) complex has been confirmed by single crystal X-ray crystallography. X-ray crystal structure analysis of the Co(II) complex revealed that the Co(II) complex consists of three Co(II) atoms coordinated by two fully deprotonated ligand (L)2- units and co-ligand NCS- anions. The close surveillance of the crystal structure of the Co(II) complex discloses some notable non-covalent interactions like H-bonding, C-H···π and π···π. The luminescent property of the Co(II) complex has been studied in methanol solution. Apart from, as a complementary revelation, intermolecular interactions with respect to percentages of hydrogen bondings in the X-ray crystal structure of the trinuclear Co(II) complex was quantified by analyses of Hirshfeld surfaces and fingerprint plots.

Crystal structure of di-ethano-lbis(thio-cyanato)-bis(urotropine)cobalt(II) and tetra-ethano-lbis(thio-cyanato)-cobalt(II)-urotropine (1/2).

The reaction of one equivalent Co(NCS)2 with four equivalents of urotropine (hexa-methyl-ene-tetra-mine) in ethanol leads to the formation of two compounds, namely, bis-(ethanol-κO)bis-(thio-cyanato-κN)bis-(urotropine-κN)cobalt(II), [Co(NCS)2(C6H12N4)2(C2H6O)2] (1), and tetra-kis-(ethanol-κO)bis-(thio-cyanato-κN)cobalt(II)-urotropine (1/2), [Co(NCS)2(C2H6O)4]·2C6H12N4 (2). In 1, the Co cations are located on centers of inversion and are sixfold coordinated by two terminal N-bonded thio-cyanate anions, two ethanol and two urotropine ligands whereas in 2 the cobalt cations occupy position Wyckoff position c and are sixfold coordinated by two anionic ligands and four ethanol ligands. Compound 2 contains two additional urotropine solvate mol-ecules per formula unit, which are hydrogen bonded to the complexes. In both compounds, the building blocks are connected via inter-molecular O-H⋯N (1 and 2) and C-H⋯S (1) hydrogen bonding to form three-dimensional networks.

Effective metal-free electrooxidative thiocyanation of anilines

An original anodic C–H thiocyanation of anilines with NH4SCN has been developed, allowing to obtain the products in 88–98% yields under potentiostatic diaphragm electrolysis on glassy carbon electrodes at Eanode = 0.60 V and moderate consumption of electricity. The preliminary voltammetric analysis included the assessment of the changes in the thiocyanate ion curve after the addition of aniline, as well as the measurements of the potentials of the reagents and products, which gave insight into mechanisms of the process (formation of thiocyanate radical and thiocyanogen) and was necessary for its optimization.

Association-Dissociation Dynamics of Ionic Electrolytes in Low Dielectric Medium.

Ionic electrolytes are known to form various complexes which exist in dynamic equilibrium in a low dielectric medium. However, structural characterization of these complexes has always posed a great challenge to the scientific community. An additional challenge is the estimation of the dynamic association-dissociation time scales (lifetime of the complexes), which are key to the fundamental understanding of ion transport. In this work, we have used a combination of infrared absorption spectroscopy, two-dimensional infrared spectroscopy, molecular dynamics simulations, and density functional theory calculations to characterize the various ion complexes formed by the thiocyanate-based ionic electrolytes as a function of different cations in a low dielectric medium. Our results demonstrate that thiocyanate is an excellent vibrational reporter of the heterogeneous ion complexes undergoing association-dissociation dynamics. We find that the ionic electrolytes exist as contact ion pairs, dimers, and clusters in a low dielectric medium. The relative ratios of the various ion complexes are sensitive to the cations. In addition to the interactions between the thiocyanate anion and the countercation, the solute-solvent interactions drive the dynamic equilibrium. We have estimated the association-dissociation dynamics time scales from two-dimensional infrared spectroscopy. The exchange time scale involving the cluster is faster than that between a dimer and an ion pair. Moreover, we find that the dynamic equilibrium between the cluster and another ion complex is correlated to the solvent fluctuations.

Transition metal precursor impact on thiocyanate complexes crystallization: Isomorphous cobalt and nickel properties

A novel hybrid organic-inorganic isomorphs, 2-Amino Piridinium di(isothiocyanate) cobalt (1) and 2-Amino Piridinium tetra(isothiocyanate)Nickel (2), were prepared by evaporation crystal growth method at room temperature and characterized by X-ray crystal structure, spectroscopic, electric and optical studies. The crystal structural analysis reveals that the solid (1) crystallizes in the monoclinic space group P 21/c and the solid (2) crystallizes in the triclinic space group P1-.In (1) the metal cations are linked by pairs of μ-1,3-bridging thiocyanate anions into corrugated chains parallel to the b direction, whereas in (2) the [Ni(NCS)4]2− anions are arranged in pairs along the c-axis direction to form anionic layers parallel to the (a, c) plane. The crystal structure of (1) and (2) was determined from XRPD data, which shows that it is strongly related to the DRX mono-crystal obtained results. Intermolecular interactions were investigated by Hirshfeld surfaces and contact enrichment tools. Different interactions packed the system through NH…N, and NH…S hydrogen bonds forming a ring. The organic entities are grouped into dimers for (2) through weak interactions NH…N and NH…S. The robustness of the crystals is also enhanced by CH…π of the piridinium ring and NH…S intermolecular interactions. HOMO and LUMO energy gaps have been computed, where Gap energies revealed a semiconductor behavior. The vibrational absorption bands were identified by infrared spectroscopy. The solid-state UV–Visible absorption spectrum and the photoluminescence spectrum of the title compounds were obtained at room temperature in order to spotlight the optical properties. The di-electrical investigations on (1) and (2) shows an interesting electrical behavior. In the [20–400 °C] range, the thermal behaviors were investigated and showed the decomposition of the two complexes with metal complexes residues.

Integrated Study of the Thiocyanate Anion Electrooxidation by Electroanalytical and Computational Methods

The mechanism of the electrochemical oxidation of thiocyanate anion in acetonitrile was studied by cyclic voltammetry, chronoamperometry, electrolysis, digital simulations and quantum chemical calculations. The experimental data indicated complex character of the reaction mechanism, which includes reactions of thiocyanate anion with the products of its oxidation, thiocyanate radical and thiocyanogen. It was proposed that the last reaction takes place in the reduction of thiocyanogen as well. The DFT PCM-SMD M06–2X/aug-CC-pVQZ calculations show that the reaction of thiocyanate anion with thiocyanate radical and disproportionation of thiocyanogen anion radical are thermodynamically favorable. The effects of the mentioned reactions on the shape of the curves of cyclic voltammetry and chronoamperometry as well as that of the mass transfer regime are discussed.

Recovery of Gold from Refractory Sulphide Concentrates by Means of Pressure Oxidation and Thiocyanate Leaching

The alternative method for gold recovery from POX cakes is thiocyanate leaching. This method has several advantages: thiocyanate is less toxic than cyanide; complex [Au(SCN)4]– is very stable (lgβ = 43.9); leaching of gold is carried out in sulfate media without CCD and neutralization of acidic POX slurry; high rate of this process; the gold oxidant is ferric ions which formed during POX of iron sulfides. The test work on pressure oxidation and thiocyanate leaching was carried out for refractory sulfide gold-copper flotation concentrate. The gold content in the concentrate was 31.8 g/t. Pressure oxidation tests at the temperature of 220 oC and the oxygen pressure of 0.7 MPa were carried out. The POX slurry to 90–95 oC was cooled and thiocyanate leaching of gold was carried out at atmospheric pressure. The concentration of thiocyanate ions was changed from 0.5 to 2 g/dm3. The recovery of gold from leaching solution was carried out by activated carbon. The loaded carbon to cyanide treatment, thermal reactivation and acidic treatment for copper and iron remove was subjected. The cyanide treatment was carried out with a sodium cyanide solution of 20 g/dm3. Thermal treatment was carried out at the temperature of 650–700 oC for 0.5 h. The acidic treatment was carried out with a hydrochloric acid solution of 20 g/dm3. After impurities removing the carbon in next experiments was used. 6 cycles gold adsorption and carbon regeneration were carried out. It was shown that thiocyanate gold leaching from POX products can be carried out in the CIP and CIL modes. Gold recovery was over 95%. 80–99% of copper, 65–88% of iron and 90–99% of sulfur were recovered from carbon during removing cycles. The gold adsorption process in each cycle had line nature. The content of gold in the loaded carbon after six cycles was 0.5 kg/t, and after long time CIP process was 3.9 kg/t. The gold stripping by alkaline solution was 97%. The gold content in the stripped carbon was 0.016 kg/t. The copper and iron content was 0.021 and 0.132 kg/t, respectively.

Electrochemical Reduction of CO2 to HCOOH over Copper Catalysts

Although great progress has been made in the field of electrochemical CO2 reduction reaction (eCO2RR), inducing product selectivity is still difficult. We herein report that a thiocyanate ion (SCN-) switched the product selectivity of copper catalysts for eCO2RR in an H-cell. A cuprous thiocyanate-derived Cu catalyst was found to exhibit excellent HCOOH selectivity (faradaic efficiency = 70-88%) over a wide potential range (-0.66 to -0.95 V vs RHE). Furthermore, it was revealed that the formation of CO and C2H4 over commercial copper electrodes could be dramatically suppressed with the presence of SCN-, switching to HCOOH. Density functional theory calculations disclosed that SCN- made the formation of HCOO* easier than COOH* on Cu (211), facilitating the HCOOH generation. Our results provide a new insight into eCO2RR and will be helpful in the development of cheap electrocatalysts for specific utilization.

Enhanced flame retardancy of flexible polyurethane foam with low loading of liquid halogen-free phosphonium thiocyanate

To achieve enhanced flame retardancy at a low dosage, a room temperature ionic liquid tetrabutylphosphonium thiocyanate (TPT) containing flame-retardant phosphorus and sulfur elements is synthesized and uniformly incorporated into flexible polyurethane foam (FPUF). FPUF containing only 3.4 wt% TPT can pass the Cal. TB117-2000 standard and exhibits a limiting oxygen index value of 23.7% without compromising thermal stability and mechanical performance. Meanwhile, the peak heat release rate of FPUF/TPT in cone calorimeter test decreases by 40.5% in comparison with that of pristine FPUF. It is revealed that the enhanced flame retardancy of FPUF/TPT originates from both the cation and the anion of TPT. The phosphonium cation contributes to the retardancy via the gas-condensed bi-phase action and the thiocyanate anion assisted the retardancy by the fuel dilution effect in the gas phase. The results indicate that the phosphorus-sulfur room temperature ionic liquids possess a great potential to act as flame retardants for fire-safety polymeric foams.

Structural evidence of the oxidation of iodide ion into hyper-reactive hypoiodite ion by mammalian heme lactoperoxidase.

Lactoperoxidase (1.11.1.7, LPO) is a mammalian heme peroxidase found in the extracellular fluids of mammals including plasma, saliva, airway epithelial lining fluids, nasal lining fluid, milk, tears, gastric juices, and intestinal mucosa. To perform its innate immune action against invading microbes, LPO utilizes hydrogen peroxide (H2 O2 ) to convert thiocyanate (SCN- ) and iodide (I- ) ions into the oxidizing compounds hypothiocyanite (OSCN- ) and hypoiodite (IO- ). Previously determined structures of the complexes of LPO with SCN- , OSCN- , and I- show that SCN- and I- occupy appropriate positions in the distal heme cavity as substrates while OSCN- binds in the distal heme cavity as a product inhibitor. We report here the structure of the complex of LPO with IO- as the first structural evidence of the conversion of iodide into hypoiodite by LPO. To obtain this complex, a solution of LPO was first incubated with H2 O2 , then mixed with ammonium iodide solution and the complex crystallized by the addition of PEG-3350, 20% (wt/vol). These crystals were used for X-ray intensity data collection and structure analysis. The structure determination revealed the presence of four hypoiodite ions in the substrate binding channel of LPO. In addition to these, six other hypoiodite ions were observed at different exterior sites. We surmise that the presence of hypoiodite ions in the distal heme cavity blocks the substrate binding site and inhibits catalysis. This was confirmed by activity experiments with the colorimetric substrate, ABTS (2,2'-azino-bis(3-ethylbenzthiazoline-sulfonic acid)), in the presence of hypoiodite and iodide ions.

Enhanced separation of nitrophenols from wastewater by using ammonium ionic liquid with thiocyanate anion in supported liquid membrane

ABSTRACT The present investigation deals with separation of various types of nitrophenols using SILM technique. Several ionic liquids were developed and the SILM parameters such as role of ILs, feed and strip phase concentration, wastewater pH, salt effect and mixture of pollutants were thoroughly investigated. The percentage extraction and stripping, flux, apparent rate constants and selectivity were evaluated. The selected ammonium IL being more polar than the imidazolium IL showed better separation of 2-nitrophenol. The SILM constituting an ammonium IL with SCN anion exhibited extraction efficiency of >96% and Ka: 0.264 h−1. The change in feed concentration showed maximum transport of nitrophenol at 300 ppm concentration (Ka: 0.673 h−1). The membranes were repeated for 4 cycles which demonstrated good stability for runs of more than 48 hours. The selectivity of 2-nitrophenol, 2,4-dinitrophenol, 2,4,6- trinitrophenol over nitrobenzene was 26, 36 and 58, respectively. The morphology of membranes was studied by using FTIR and FE-SEM and the transport mechanism was elucidated. With the optimized parameters, a concentration factor of 7 can be achieved in the present SILM system. The application of SILM including ammonium IL with SCN anion shows a promising potential for the treatment of various types of nitrophenol bearing wastewater.

Thiocyanate increases the nitrous oxide formation process through modifying the soil bacterial community.

Nitrous oxide (N2 O) is a potent greenhouse gas depleting the stratospheric ozone. Previous studies reported that the thiocyanate (TC) excretion in the urine of cattle fed rapeseed meals containing glucosinolates was positively correlated with the N2 O-nitrogen (N) emissions. The objectives of the experiment were to verify the effects and the mechanism of TC on the N2 O-N emissions from the soil applied with artificial urine using static incubation technique. Four levels of TC, that is 0.00, 0.26, 0.78 and 2.33 mmol L-1 were composited in artificial urine as experimental treatments. Soil inorganic N and bacterial community were analyzed to elucidate the effects of TC on the N2 O-N emissions of artificial urine. Adding TC increased the N2 O-N fluxes, the N2 O-N to N application ratio, and the estimated N2 O-N emissions from the soil applied with artificial urine both linearly and quadratically. The estimated N2 O-N emission (Y, in μmol) was increased with the TC adding level (X, in μmol) in a quadratic manner: (R 2 =0.70). Adding TC did not affect the soil bacterial diversity and richness, but increased the relative abundances of Nitrosomonas (both for nitrification and denitrification) and Hyphomicrobium, Lysobacter and Terrimonas (for denitrification), and tended to increase the relative abundances of denitrification and dissimilatory nitrate reduction to ammonium. TC increased the N2 O-N emissions of the soil applied with artificial urine possibly through enhancing the denitrification of nitrifiers in the soil. Field experiments are necessary to verify the laboratory results. © 2021 Society of Chemical Industry.

Comparison of the crystal structures of the low- and high-temperature forms of bis-[4-(di-methyl-amino)-pyridine]-dithio-cyanato-cobalt(II).

Single crystals of the high-temperature form I of [Co(NCS)2(DMAP)2] (DMAP = 4-di-methyl-amino-pyridine, C7H10N2) were obtained accidentally by the reaction of Co(NCS)2 with DMAP at slightly elevated temperatures under kinetic control. This modification crystallizes in the monoclinic space group P21/m and is isotypic with the corresponding Zn compound. The asymmetric unit consists of one crystallographically independent Co cation and two crystallographically independent thio-cyanate anions that are located on a crystallographic mirror plane and one DMAP ligand (general position). In its crystal structure the discrete complexes are linked by C-H⋯S hydrogen bonds into a three-dimensional network. For comparison, the crystal structure of the known low-temperature form II, which is already thermodynamically stable at room temperature, was redetermined at the same temperature. In this polymorph the complexes are connected by C-H⋯S and C-H⋯N hydrogen bonds into a three-dimensional network. At 100 K the density of the high-temperature form I (ρ = 1.462 g cm-3) is higher than that of the low-temperature form II (ρ = 1.457 g cm-3), which is in contrast to the values determined by XRPD at room temperature. Therefore, these two forms represent an exception to the Kitaigorodskii density rule, for which extensive inter-molecular hydrogen bonding in form II might be responsible.

Synthesis and crystal structure of di-aqua-bis-(hexa-methyl-enetramine-κN)bis-(thio-cyanato-κN)cobalt(II)-hexa-methyl-ene-tetra-mine-aceto-nitrile (1/2/2).

The crystal structure of the title solvated coordination compound, [Co(NCS)2(C6H12N4)2(H2O)2]·2C6H12N4·2C2H3N, consists of discrete complexes in which the Co2+ cations (site symmetry ) are sixfold coordinated by two N-bonded thio-cyanate anions, two water mol-ecules and two hexa-methyl-ene-tetra-mine (HMT) mol-ecules to generate distorted trans-CoN4O2 octa-hedra. The discrete complexes are each connected by two HMT solvate mol-ecules into chains via strong O-H⋯N hydrogen bonds. These chains are further linked by additional O-H⋯N and C-H⋯N and C-H⋯S hydrogen bonds into a three-dimensional network. Within this network, channels are formed that propagate along the c-axis direction and in which additional aceto-nitrile solvent mol-ecules are embedded, which are hydrogen bonded to the network. The CN stretching vibration of the thio-cyanate ion occurs at 2062 cm-1, which is in agreement with the presence of N-bonded anionic ligands. XRPD investigations prove the formation of the title compound as the major phase accompanied by a small amount of a second unknown phase.

Regulation of lead oxide on Cyaniding Behavior of chalcopyrite

During the cyanidation of gold‑copper ores and concentrates, the chalcopyrite significantly increases cyanide consumption. The effects of PbO on the chalcopyrite dissolution mechanisms were studied by SEM and XPS analyses during cyanation. A small amount of PbO could promote the dissolution of chalcopyrite, while more PbO would inhibit dissolution. When 0.5 g/L PbO was added, the main lead compound on the surface of chalcopyrite was PbS, which could enhance the electron transfer between cyanide and chalcopyrite, thus facilitating the dissolution of chalcopyrite. The amount of PbS precipitates increased in the leaching system when the amount of PbO was more than 0.5 g/L. This reduced prominently the free sulfide ions concentration in the solution. PbS would be oxidized to form thiocyanate and lead (II) ions when the concentration of sulfur ions decreased continuously in the solution. These lead (II) ions would react with OH– to form Pb(OH)2 precipitates, which attach to the surfaces of chalcopyrite and inhibit its dissolution in cyanide solutions. The developed method can not only improve the leaching rate of gold but also reduce the consumption of reagents.

Study on Simulation Technology in Chemical Equilibrium Experimental Teaching

Chemical simulation technology is a new experimental method that utilizes computer programs and applications to simulate and calculate objective substances, chemical reaction processes and status. In this paper, chemical equilibrium simulation technology is applied to the experimental teaching of liquid phase reaction equilibrium in chemical basic experiments. Taking the chemical equilibrium experimental teaching of iron ions and thiocyanate ions as an example, the distribution coefficient diagram, ion activity diagram, component solubility diagram and component stable equilibrium phase diagram under double influence factors are simulated dynamically, which provides great help for students to further understand the chemical equilibrium visually. At the same time, it is helpful to determine the optimal experimental concentration of reactants and has certain practical guiding significance for the optimization of an experimental scheme in a teaching experiment.