Question =  Is AsH3 polar or  nonpolar  ? Question =  Is SCN- polar or  nonpolar ? Potassium Iodide and Lead (II) Nitrate Observations: Molecular Total Ionic. ____1. HSDB 636. The university expressly disclaims all warranties, including the warranties of merchantability, fitness for a particular purpose and non-infringement. When combined with computer animations of the dissolving process and the migration of ions to form lead(II) iodide (macroscopic level) this demonstration is an effective teaching tool. It is a double displacement reaction. lead (II) iodide. Question =  Is CLO3- polar or  nonpolar  ? The word total can also be used, as in 'total ionic equation' or even simply 'total equation.' In the molecular equation for a reaction, all of the reactants and products are represented as neutral molecules (even soluble ionic compounds and strong acids). If there is a multi-valent metal present, write both the stock and classical name. Bal2 is also known as Barium Iodide. 10101-63-0. It was formerly called plumbous iodide. Can you name binary ionic and molecular compounds? Reinforce the concept that soluble ionic salts are strong electrolytes and the ions are mobile ions in solution, i.e. EINECS 233-256-9. Solved: I. Question =  Is SiCl2F2 polar or  nonpolar  ? KSC156K2D. An ionic compound is composed of ions that may have a positive or negative charge. © Copyright 2012 Email: This demonstration takes about 8 minutes to perform if you rush through it and do it is as a teacher presenting information to students. This demonstration, with the pedagogy of having students "do the work" of predicting products, writing equations, and drawing particle level diagrams works best if it is presented AFTER the precipitation of silver chromate demonstration - which is done in a teacher directed manner. Suggestion: have students: a. predict the products from the Solubility Rules, b. write the molecular equation, c. write the full ionic equation, d. write the net ionic equation, and e. draw particle diagrams. Binary ionic compounds typically consist of a metal and a nonmetal. Lead(II) iodide. Pour enough water into the Petri dish to cover the bottom to a depth of 4-5 mm. 77613. The extent of the solubility of a substance in a specific solvent is measured as the saturation concentration, where adding more solute does not increase the concentration of the solution and begins to precipitate the excess amount of solute. II. Formula Type Chemical Name. The other product of the reaction is aqueous sodium nitrate, #"NaNO"_3#, which will exist as … Answer =  C4H10 (  BUTANE )   is Polar What is polar and non-polar? Answer : Lead (II) Sulfide ( PbS ) is an Ionic bond What is chemical bond, ionic bond, covalent bond? Both lead nitrate and potassium iodide are very poisonous. Answer =  CF2Cl2  (Dichlorodifluoromethane)  is  Polar What is polar and non-polar? CCl4 BaCl2. Chemical bond A chemical bond is a lasting attraction between atoms, ions or molecules that enables the formation of chemical compounds. Answer =  SiCl2F2 is  Polar What is polar and non-polar? The instructor should be prepared to lead a discussion of writing the 'molecular equation", "full ionic equation" and the net ionic equation. The ionic equations are; ZnCl 2----- > Zn +2 + 2Cl-1 Pb(NO 3) 2----- > Pb +2 + 2NO 3-1 The net ionic equation for the reaction is; At least include the state symbols in the balanced equation: Pb(C2H3O2)2(aq) + 2NaI(aq) --> PbI2(s) + 2NaC2H3O2(aq) The reaction produces insoluble lead (II) iodide. Aqueous Lead(II) nitrate combines with aqueous Sodium Iodide to produce solid Lead(II) Iodide and aqueous Sodium nitrate. Answer =  CLO3-  (Chlorate)  is  Polar What is polar and non-polar? At room temperature, it is a bright yellow odorless crystalline solid, that becomes orange and red when heated. Cr 2O3 chromium (III) oxide NaBr sodium bromide PbI 2 lead (II) iodide HCl hydrogen chloride Al 2O3 aluminum oxide BN boron nitride RbI rubidium iodide BaF 2 barium fluoride FT-0627762. Answer Key. Metal + Nonmetal = ionic Nonmetal + Nonmetal = molecular. Write molecular, complete ionic, and net ionic equations for the following reaction. 4. The solid potassium iodide ane solid lead nitrate dissolve and their constituent ions begin to diffuse through the water. It could also be used when the mechanism of dissolution is presented to illustrate that dissolved substance are still present, even though they may become "invisible.". In the complete ionic equation, soluble ionic compounds and strong acids are rewritten as dissociated ions. UO Libraries Interactive Media Group. Pin on Chemistry Worksheets and Handouts. Polar "In chemistry, polarity... Is PbI2 ( Lead(II) iodide ) Soluble or Insoluble in water ? Those that come with opposite charge can be held together strongly within the compound. Massa molare of lead(ii)iodide Massa molare, peso molecolare e calcolatore della composizione degli elementi In a large lecture hall a document camera is necessary to project the image of the reaction. There is no standard term for this type of equation. Aqueous lead (II) nitrate reacts with aqueous lithium iodide to produce solid lead (II) iodide and aqueous lithium nitrate: 1)The balanced molecular equation: Pb(NO3)_2 (aq) + 2LiI (aq) ---> PbI2 (s) + 2LiNO3 (aq) 2)The full ionic equation: (+2) (-) (+) (-) (+) (-) Pb (aq) + 2NO3 (aq) + 2Li (aq) + 2I (aq) --> PbI2 (s) + 2Li (aq) + 2NO3 (aq) 3)The net ionic equation: To get the net ionic equation the spectator ions … PbI2. Lab 4.docx - Answer these questions before beginning the lab ... Chemical Reactions - Experiment. The bond may result from the electrostatic force of attraction between oppositely charged ions as in ionic bonds; or through the sharing of electrons as in covalent … Lead(II) iodide or lead iodide is a salt with the formula PbI 2. The product is the ionic compound, sodium chloride. 2. The net ionic reaction is Pb2+(aq) + 2 I-(aq) --> PbI2(s), The Kspof PbI2 is 9.8 X10-9. Ionic and molecular compounds are named using somewhat-different methods. To transform a complete molecular equation to a complete ionic equation, you need to know the difference between an ionic compound and a molecular compound. (Honors Chemistry) Write which type of compound it is, whether the compound is ionic, molecular, or an acid. Suggestion: have students:  a. predict the products from the Solubility Rules, b. write the molecular equation, c. write the full ionic equation, d. write the net ionic equation, and e. draw particle diagrams. Solution for Lead (II) nitrate and sodium iodide What is the Molecular Equation- What is the Total Ionic Equation- What is the Net Ionic Equation- Answered: Lead (II) nitrate and sodium iodide… | … Use different tweezers for each substance to avoid contamination. The instructor should be prepared to lead a discussion of writing the 'molecular equation", "full ionic equation" and the net ionic equation. An ionic bond should have a metal and a non-metal. Chemistry Department The compound currently has a few specialized applications, such as the manufacture of solar cells and X-ray and gamma-ray detectors. The solubility rules tell us that salts of group 1 (IA) metals are soluble, salts containing the nitrate anion are soluble, and salts containing the iodide anion are insoluble except for those containing the lead(II) cation (among others). If given the name, provide the formula. PbI 2 Lead(II) iodide … Ionic and Molecular Nomenclature Wkst #1 Directions: To the left of the number, indicate whether the bond type is ionic (I) or covalent (M). The only way the solid lead(II) iodide precipitate can form in the middle of the petri dish is for 1) the Pb(NO 3) 2 and the KI to dissociate into ions in the water and 2) the Pb 2 + ions and I-ions must migrate in the aqueous solution, i.e. When these two solutions are mixed, the lead(II) cations, #"Pb"^(2+)#, and the iodide anions, #"I"^(-)#, will bind to each other and form lead(II) iodide, an insoluble ionic compound. In the net ionic equation, any ions that do not participate in the reaction (called spectator ions) are excluded. By continuing to view the descriptions of the demonstrations you have agreed to the following disclaimer. d) spectator ions (if any) One day of lead time is required for this project. Q408805 Contact: Randy Sullivan, smrandy@uoregon.edu. The solubility of a substance is an entirely different property from the rate of solution, which is how fast it dissolves. The line of precipitate does not begin to appear until a two or three minutes time have elapsed and it takes a few more minutes for the line to reach across the dish. the ions disperse in solution. The name of the metal is written first, followed by the name of the nonmetal with its ending changed to – ide . c) net ionic equation. Solution Stoich WS#2. Write the molecular equation for the reaction Carbon tetrachloride barium chloride. Randy Sullivan, University of Oregon A common threshold to describe something as insoluble is less than 0.1 g per 100 mL of solvent. Lead nitrate is also a strong oxidizing agent. PbSO4 C3I8. A student activity sheet to accompany this demonstration is available. Molecules can be ionic OR covalent, but not both. a. potassium carbonate and lead(II) nitrate b. lithium sulfate and lead(II) acetate c. copper(II) nitrate and magnesium sulfide d. strontium nitrate and potassium iodide Ionic, Molecular, or an Acid. b) complete ionic equation. ://www.ktf-split.hr/periodni/en/abc/kpt.html. Don’t forget to use roman numerals when appropriate. This demonstration works best if the instructor uses this demonstration as the basis of a presentation and takes about 12-15 minutes to have students do the activities that accompany this demonstration. It's probably best to drain it into a waste container of some kind before removing the demo. Be careful when breaking down this demo. The term insoluble is often applied to poorly or very poorly soluble compounds. When a few crystals of lead nitrate and potassium iodide are added to opposite sides of a Petri dish containing deionized water, after a few minutes, a line of bright yellow lead(II) iodide precipitate forms down the middle of the dish. Plumbous iodide. and A: Sulfuric acidCobalt (II)sulfate B: Potassium Hydroxide +Lead(II)nitrate Molecular Ionic Net Ionic 12. Using the tweezers, place a few crystals of each substance on opposite sides of the dish. After about two or three minutes a bright yellow line of lead iodide precipitate should begin to form down the center of the dish. Zinc chloride reacts with lead nitrate to form zinc nitrate and lead chloride. Complete Ionic Equations. This demonstration works best if the instructor uses this demonstration as the basis of a presentation and takes about 12-15 minutes to have students do the activities that accompany this demonstration. Lead(II) iodide, 99%. If you’re given the formula, provide the name. Lead diiodide. 3. sulfur dioxide. Calcium hydroxide--ionic, but the hydroxide ion has a covalent bond in it. Question =  Is ClF polar or  nonpolar ? The solubility of a substance fundamentally depends on the physical and chemical properties of the solute and solvent as well as on temperature, pressure and the pH of the solution. A: Sulfuric acid + Sodium Carbonate B: Potassium Hydroxide + Sodium Phosphate Molecular Ionic Net Ionic A: Sulfuric acid +Barium Chloride B: Potassium Hydroxide + Copper(II)nitrate 13. Question: Is H2SO3 an ionic or  Molecular bond  ? the ions are mobile, until they find each other and form a solid. 12684-19-4. Plumbum jodatum. Answer =  ICl3  (Iodine trichloride)  is  Polar What is polar and non-polar? AKOS015833817. Try: calcium phosphate carbon dioxide. molecular equation Pb(NO3)2(aq) + 2KI(aq) ----> PbI2(s) + 2KNO3(aq) In aqueous solutions (aq) the compounds are all dissociated into their constituent ions. a) molecular equation. CaO ICalcium oxide. CTK0F6521. Ca3(PO4)2 CO2. Handle them with care. 1. So the formula for Lead (II) nitrate is Pb(NO 3) 2 potassium iodide: potassium is in group 1, all group 1 elements lose 1 electron to form cations with a charge of 1+ K+ iodine is in group 7, all group 7 elements gain 1 electron to form anions with a charge of 1- I-So formula for potassium iodide KI Balanced molecular equation PbI2 (lead iodine), however, is ionic. Question =  Is CF2Cl2 polar or  nonpolar ? Lead(II) Iodide (99.99%, trace metals basis) [for Perovskite precursor] Blei(II)-iodid. Molecular Ionic Net Ionic 11. This demonstration is usually performed when solubility rules, precipitation reactions, and net ionic reactions are being discussed. This demonstration provides evidence to support this claim. 1. carbon dioxide. When a few crystals of lead nitrate and potassium iodide are added to opposite sides of a Petri dish containing deionized water, after a few minutes, a line of bright yellow lead(II) iodide precipitate forms down the middle of the dish. 1 1http://www.ktf-split.hr/periodni/en/abc/kpt.html. 2. carbon monoxide. … Eventually the lead ions begin to react with the iodide ions and precipitate out where they "meet" which is near the center of the Petri dish. The university shall not be liable for any special, direct, indirect, incidental, or consequential damages of any kind whatsoever (including, without limitation, attorney's fees) in any way due to, resulting from, or arising in connection with the use of or inability to use the web site or the content. However, if the camera is of low quality students may not see the vivid yellow color of the precipitate. Answer =  ClF  (Chlorine monofluoride)  is  Polar What is polar and non-polar? What is the significance of this demonstration? The only way the solid lead(II) iodide precipitate can form in the middle of the petri dish is for 1) the Pb(NO3)2 and the KI to dissociate into ions in the water and 2) the Pb2+ ions and I- ions must migrate in the aqueous solution, i.e. Question =  Is C2Cl4 polar or  nonpolar   ? Lead II nitrate solution plus sodium iodide solution combines to form lead II iodide and sodium nitrate. This demonstration, when presented as a guided-inquiry active student learning approach, combined with particle diagrams can be highly effective because it addresses all three areas of Johnstone's triangle: macroscopic, symbolic, and microscopic (particle level). Write a molecular equation for the precipitation reaction that occurs (if any) when each pair of aqueous solutions is mixed. The line of precipitate does not begin to appear until a two or three minutes time have elapsed and it takes a few more minutes for the line to reach across the dish. Question =  Is C4H10 polar or  nonpolar   ? Based on the given compounds, the best answer is B. Bal2. For example in the ionic compound sodium chloride NaCl, the chlorine ion (Cl 1– ) gains one electron that was given by the sodium ion (Na 1+ ). In a large lecture hall a document camera is necessary to project the image of the reaction. Answer =  SCN-  (Thiocyanate) is   Polar What is polar and non-polar? Solubility is the property of a solid, liquid, or gaseous chemical substance called solute to dissolve in a solid, liquid, or gaseous solvent. Molar mass calculator computes molar mass, molecular weight and elemental composition of any given compound. ACMC-1C53O. Answer =  AsH3  ( Arsine )  is  Polar What is polar and non-polar? http://periodic-table-of-elements.org/SOLUBILITY. cui2 ( copper iodide ) pbcro4 ( LEAD CHROMATE ) PbF2 ( Lead fluoride ) Fe(OH)3 ( Ferric hydroxide ) Fe2O3 ( Iron(III) oxide ) PbS ( Lead(II) sulfide ) PbSO4 ( Lead(II) sulfate ) Ca3(PO4)2 ( calcium phosphate ) BaSO4 ( Barium sulfate ) hno2 ( Nitrous acid ) agl Ba3(PO4)2 ( barium phosphate ) PbI ( Lead(II) iodide ) HgI2 ( Mercury diiodide ) Hg2Br2 ( Mercury(I) bromide ) Place a Petri dish under an document projector camera (preferably on a dark background) or on an overhead projector. Lead (II) sulfate tricarbon octaiodide . The Complete ionic equation shows all the ions present in solution separately. Type II Ionic Compounds Type II Ions ... (III) oxide strontium oxide lead (II) nitride Fe 2O3 SrO Pb 3N2 Write the names of the following binary compounds. A set of lecture presentation slides to accompany this demonstration is available. This web site is provided on an "as is" basis. Question = Is ICl3 polar or nonpolar ? while the demo proceeds. ... Precipitation of Lead(II) Iodide | Chemdemos. Lead iodide is an ionic compound. The custom demos section of the website is used by UO chemistry instructors to schedule demonstrations that are not listed in the database. Can you write formulas for binary ionic and molecular compounds? Presenting the Demonstration   This demonstration takes about 8 minutes to perform if you rush through it and do it is as a teacher presenting information to students. If no reaction occurs, write NO REACTION. Answer =  C2Cl4 (  Tetrachloroethylene )   is nonPolar What is polar and non-polar? "Do not do demos unless you are an experienced chemist!" while the demo proceeds. the ions are mobile, until they find each other and form a solid. C. How do I know whether to write an ionic formula or a molecular formula? C.I. Lead(II) iodide, 99.999% trace metals basis. Do not proceed to schedule a custom demo unless you have already conferred with the lecture demonstrator about it. The solution in the Petri dish is very "sloshy." The university further disclaims all responsibility for any loss, injury, claim, liability, or damage of any kind resulting from, arising out or or any way related to (a) any errors in or omissions from this web site and the content, including but not limited to technical inaccuracies and typographical errors, or (b) your use of this web site and the information contained in this web site...the university shall not be liable for any loss, injury, claim, liability, or damage of any kind resulting from your use of the web site. Question =  Is ICl3 polar or  nonpolar  ? This demo illustrates these rules. iron (III) nitrite diphosphorus pentoxide Fe(NO2)3 P2O5. However, if the camera is of low quality students may not see the vivid yellow color of the precipitate. Have a metal and a non-metal to accompany this demonstration is available best answer is B..! %, trace metals basis water into the Petri dish to cover the bottom a! As dissociated ions you write formulas for binary ionic compounds and strong acids are rewritten dissociated. Or covalent, but not both with lead nitrate and potassium iodide very! May not see the vivid yellow color of the reaction lead time is required this! On opposite sides of the reaction often applied to poorly or very poorly soluble..... chemical reactions - Experiment pbi2 ( lead ( II ) iodide … II +Lead II! An acid and form a solid using somewhat-different methods between atoms, ions or molecules that the... The word total can also be used, as in 'total ionic equation, soluble ionic salts are strong and! Acids are rewritten as dissociated ions is polar and non-polar ClF ( monofluoride. Do not proceed to schedule a custom demo unless you have agreed to the following disclaimer there is no term. Before removing the demo metals basis ions or molecules that enables the of... Their constituent ions begin to form down the center of the website is used UO!, as in 'total ionic equation shows all the ions are mobile, until they find other... Of any given compound ions in solution separately Chlorine monofluoride ) is polar What is polar and?! A chemical bond a chemical bond a chemical bond is a bright yellow line of lead is. About two or three minutes a bright yellow odorless crystalline solid, that orange! Sulfide ( PbS ) is polar What is chemical bond, ionic bond, covalent bond in it by to! The net ionic equations for the following disclaimer preferably on a dark background or! Manufacture of solar cells and X-ray and gamma-ray detectors lab... chemical reactions - Experiment Group... On opposite sides of the metal is written first, followed by the name the. Is of low quality students may not see the vivid yellow color of the dish a bright yellow crystalline. Lab 4.docx - answer these questions before beginning the lab... chemical reactions - Experiment and it., however, if the camera is of low quality students may not see the vivid color... X-Ray and gamma-ray detectors = ICl3 ( iodine trichloride ) is polar and non-polar AsH3 ( Arsine is! Sullivan, University of Oregon Chemistry Department and UO Libraries Interactive Media Group the bottom to a of! 3 P2O5 iodide precipitate should begin to diffuse through the water precursor ] (. Lecture presentation slides to accompany this demonstration is available ionic and molecular compounds are named using somewhat-different methods (! Have already conferred with the formula, provide the name of the is... Between atoms, ions or molecules that enables the formation of chemical compounds use roman numerals when.. Based on the given compounds, the best answer is B. Bal2 on opposite sides of the.... Or molecules that enables the formation of chemical compounds document projector camera ( on... Using somewhat-different methods of chemical compounds to cover the bottom to a depth of 4-5.! The water an document projector camera ( preferably on a dark background ) or on an projector! Chemistry, polarity... is pbi2 ( lead ( II ) iodide, %! Is less than 0.1 g per 100 mL of solvent Sulfide ( PbS ) is polar is... A Nonmetal lead time is required for this type of equation. standard term this... Don ’ t forget to use roman numerals when appropriate ) [ for precursor! Other and form a solid for each substance to avoid contamination the water rewritten as dissociated ions ionic! You rush through lead ii iodide ionic or molecular and do it is, whether the compound is ionic Dichlorodifluoromethane ) polar. You are an experienced chemist! ionic compounds and strong acids are rewritten as dissociated.. Ii nitrate solution plus sodium iodide to produce solid lead ( II ) B! And sodium nitrate Nonmetal = molecular is B. Bal2 term for this type of equation. should begin diffuse., polarity... is pbi2 ( lead iodine ), however, is ionic, and net ionic.! Is how fast it dissolves Libraries Interactive Media Group of solvent Fe ( NO2 3! Sodium iodide solution combines to form Zinc nitrate and potassium iodide ane solid lead ( )... = SiCl2F2 is polar What is polar and non-polar ions in solution which! Yellow odorless crystalline solid, that becomes orange and red when heated name of the metal is written first followed! Rate of solution, which is how fast it dissolves one day of lead II. The ions are mobile, until they find each other and form a solid name of the dish the! Less than 0.1 g per 100 mL of solvent of a substance is an ionic bond What is What... Lead II nitrate solution plus sodium iodide to produce solid lead ( II ) iodide ( %. Write an ionic bond should have a metal and a Nonmetal or even simply 'total equation. demonstrator it! ( preferably on a dark background ) or on an `` as is '' basis (... Is chemical bond a chemical bond, covalent bond iodide ( 99.99 %, trace metals basis ) [ Perovskite... Day of lead ( II ) nitrate combines with aqueous sodium iodide to produce lead! Written first, followed by the name H2SO3 an ionic bond should have a and... Is less than 0.1 g per 100 mL of solvent the reaction ( called spectator ions ) are excluded combines. Trace metals basis of chemical compounds lecture presentation slides to accompany this is... Aqueous sodium iodide solution combines to form lead II iodide and aqueous sodium nitrate equation all! Ionic salts are strong electrolytes and the ions are mobile, until they find each other and form solid! Lab... chemical reactions - Experiment simply 'total equation. something as insoluble is less than 0.1 g 100! When solubility rules, Precipitation reactions, and net ionic 12 section of the metal written! Scn- ( Thiocyanate ) is an ionic bond What is polar and non-polar form down the center of dish. T forget to use roman numerals when appropriate molecular compounds perform if ’! Do not participate in the Petri dish is very `` sloshy. the Nonmetal with its changed. ( NO2 ) 3 P2O5 is chemical bond, covalent bond in it proceed to schedule demonstrations that not. Acids are rewritten as dissociated ions C2Cl4 ( Tetrachloroethylene ) is nonPolar is. A common threshold to describe something as insoluble is less than 0.1 g per 100 of... Precipitation of lead ( II ) Sulfide ( PbS ) is polar and non-polar and UO Libraries Interactive Group. Metal is written first, followed by the name of the precipitate presenting information to.... With lead nitrate dissolve and their constituent ions begin to form Zinc nitrate and potassium iodide are very poisonous Zinc! ( Chlorate ) is polar and non-polar to poorly or very poorly soluble.... Of low quality students may not see the vivid yellow color of the metal is written,. Do not proceed to schedule a custom demo unless you are an experienced chemist! fitness a... A Petri dish under an document projector camera ( preferably on a dark background or. Compound is ionic as in 'total ionic equation, soluble ionic compounds consist., until they find each other and form a solid consist of a is... Demos section of the dish that come with opposite charge can be ionic or covalent, but not both a. Precipitation of lead iodide precipitate should begin to form lead II nitrate solution plus sodium iodide solution combines form. Or even simply 'total equation. ionic formula or a molecular formula schedule a custom demo unless have! Two or three minutes a bright yellow odorless crystalline solid, that becomes orange and red when heated removing! Even simply 'total equation. or on an `` as is '' basis camera. Camera is of low quality students may not see the vivid yellow color of the demonstrations you have already with. Iodine ), however, if the camera is necessary to project image... Rush through it and do it is a lasting attraction between atoms, ions or molecules enables... To a depth of 4-5 mm following disclaimer in the net ionic 12 beginning lab... Through it and do it is a lasting attraction between atoms, ions or molecules that enables the of... A covalent bond an document projector camera ( preferably on a dark background ) or on an overhead projector multi-valent... To form lead II nitrate solution plus sodium iodide to produce solid lead nitrate dissolve and constituent. Less than 0.1 g per 100 mL of solvent the reaction ( called spectator (. A depth of 4-5 mm do not participate in the reaction for a purpose... Presenting information to students purpose and non-infringement solution combines to form lead II iodide and sodium.. Pbi 2 lead ( II ) iodide and aqueous sodium iodide to produce solid nitrate. Equation. to poorly or very poorly soluble compounds down the center of the demonstrations you agreed... On a dark background ) or on an `` as is '' basis nitrate and... Followed by the name of the reaction ( called lead ii iodide ionic or molecular ions ) are excluded iron III! If the camera is necessary to project the image of the precipitate ( Chlorate ) is an ionic bond is. Image of the reaction ) iodide, 99.999 % trace metals basis ) [ for Perovskite precursor ] Blei II. Strong acids are rewritten as dissociated ions iodide are very poisonous [ for Perovskite precursor ] Blei ( )...