The complex formed between copper II ion and ethylenediamine ligand has a coordination number of 4 and a square planar geometrical shape. The complex is known as bis ethylenediamine copper II complex, with the formula [Cu en 2]^2+.Synthesis:1. Dissolve 5 g of copper II sulfate pentahydrate CuSO45H2O in 50 mL of distilled water in a beaker.2. In a separate beaker, dissolve 6 g of ethylenediamine en in 50 mL of distilled water.3. Slowly add the ethylenediamine solution to the copper II sulfate solution while stirring.4. A blue precipitate will form initially, which will then dissolve to form a deep blue solution.5. Allow the reaction to proceed for 30 minutes with continuous stirring.6. Filter the solution to remove any unreacted starting materials.7. Slowly evaporate the solvent to obtain blue crystals of the bis ethylenediamine copper II complex.Characterization:1. Elemental analysis: The elemental composition of the complex can be determined by analyzing the percentage of copper, nitrogen, carbon, and hydrogen in the sample.2. Infrared IR spectroscopy: The presence of ethylenediamine ligands can be confirmed by the characteristic absorption bands of the NH2 and CH2 groups in the IR spectrum.3. Ultraviolet-visible UV-Vis spectroscopy: The square planar geometry of the complex can be confirmed by the d-d transition bands in the UV-Vis spectrum. The complex will show a strong absorption band around 600-800 nm, corresponding to the d-d transition of the copper II ion in a square planar environment.4. X-ray crystallography: The crystal structure of the complex can be determined by X-ray diffraction analysis, which will confirm the square planar geometry and coordination number of 4.5. Magnetic susceptibility measurements: The complex is expected to be diamagnetic due to the d9 electronic configuration of the copper II ion in a square planar environment.Spectroscopic analysis results:1. IR spectrum: The presence of ethylenediamine ligands will be confirmed by the characteristic absorption bands of the NH2 3200-3500 cm^-1 and CH2 2800-3000 cm^-1 groups.2. UV-Vis spectrum: The d-d transition band will be observed around 600-800 nm, confirming the square planar geometry of the complex.