Inorganic: Experiments Woollins.pdf Patched

This report follows standard academic formatting for inorganic chemistry.

LABORATORY REPORT Experiment Title: Synthesis and Analysis of Potassium Tris(oxalato)ferrate(III) Trihydrate Source: Woollins, J.D. Inorganic Experiments Date Performed: [Insert Date] Student Name: [Insert Name]

1. Abstract This experiment details the synthesis of the coordination complex potassium tris(oxalato)ferrate(III) trihydrate, $K_3[Fe(C_2O_4)_3]\cdot 3H_2O$. The synthesis was achieved via a two-step process involving the preparation of ferrous oxalate intermediate followed by oxidation and coordination in the presence of excess oxalate. The product was characterized by yield calculation, visual inspection of color, and qualitative chemical tests to confirm the presence of iron(III) and oxalate ligands. The synthesis resulted in emerald-green crystals with a percentage yield of [Insert %].

2. Introduction Coordination chemistry is a fundamental area of inorganic chemistry focusing on compounds formed between central metal atoms and surrounding ligands. Potassium tris(oxalato)ferrate(III) is a classic example of a coordination complex where iron acts as the central metal ion and the oxalate ion ($C_2O_4^{2-}$) acts as a bidentate ligand. The synthesis typically proceeds through an intermediate. First, iron(II) ammonium sulfate reacts with oxalic acid to form yellow ferrous oxalate. This intermediate is then oxidized by hydrogen peroxide in the presence of potassium oxalate to form the final Iron(III) complex. The reaction is advantageous for teaching labs as it demonstrates ligand substitution, oxidation-reduction, and crystallization techniques. Relevant Chemical Equations: Inorganic Experiments Woollins.pdf

Formation of Intermediate: $$Fe^{2+} + H_2C_2O_4 + 2H_2O \rightarrow FeC_2O_4\cdot 2H_2O (s) + 2H^+$$ Oxidation and Coordination: $$2FeC_2O_4(s) + H_2O_2 + 3K_2C_2O_4 + H_2C_2O_4 \rightarrow 2K_3[Fe(C_2O_4)_3]\cdot 3H_2O$$

3. Experimental Section 3.1 Materials

Ferrous ammonium sulfate hexahydrate ($Fe(NH_4)_2(SO_4)_2\cdot 6H_2O$) Sulfuric acid ($H_2SO_4$) Oxalic acid ($H_2C_2O_4$) Potassium oxalate ($K_2C_2O_4$) Hydrogen peroxide ($H_2O_2$, 3% or 20%) Ethanol (for washing) Abstract This experiment details the synthesis of the

3.2 Procedure

Preparation of Ferrous Oxalate: A solution of ferrous ammonium sulfate (5.0 g) in dilute sulfuric acid was prepared. A solution of oxalic acid was added dropwise with stirring. A yellow precipitate of ferrous oxalate formed immediately. The precipitate was collected via suction filtration and washed with warm water to remove sulfate ions. Oxidation: The moist yellow precipitate was transferred to a beaker. A solution of potassium oxalate (2.5 g) was added. The mixture was heated to 40°C. Hydrogen peroxide was added dropwise with vigorous stirring until the yellow solid dissolved and the solution turned brown/green, indicating oxidation to Iron(III). Crystallization: The solution was heated further to concentrate, then cooled in an ice bath. Emerald green crystals formed. Isolation: The crystals were collected via suction filtration, washed with a small amount of ice-cold water followed by ethanol, and allowed to dry.

4. Results 4.1 Observations

Step 1: The initial mixture turned bright yellow upon the addition of oxalic acid, consistent with the formation of $FeC_2O_4\cdot 2H_2O$. Step 2: Upon addition of $H_2O_2$, effervescence (oxygen gas evolution) was observed. The yellow solid dissolved, and the solution turned a deep brown/red color initially, eventually stabilizing to a clear green solution upon heating. Product: The final product appeared as emerald-green, monolithic crystals.

4.2 Yield Calculation