09/06/2012
Introduction
The objective of this project was to prepare tin tetraiodide through the following reaction:
Sn+2I2∆SnI4
and to measure the melting point of tin tetraiodide. Tin tetraiodide was recrystallized after the synthesis. The percent yield and the theoretical yield of tin tetraiodide were calculated. Recrystallization is to further improve the purity of tin tetraiodide. The solvent is carefully chosen to be toluene in order to maximize the recovery of tin tetraiodide during recrystallization.
Experimental method1
Approximately 2.50g iodide and 1.01g tin were weighed on a balance and were placed in an Erlenmeyer flask. Approximately 10ml toluene was added to the flask. The mixture was heated on a hot plate at almost boiling temperature and was stirred using a stirring rod till the purple color in the flask faded. The solution was gravity filtered to remove solid impurities. The filtrate was set aside to cool to room temperature and was set in an ice bath for complete recrystallization for 30 minutes. The cooled mixture was suction filtered. The obtained tin tetraiodide was weighed. The crude tin tetraiodide and 5ml toluene were added into a beaker and were heated on the plate till all solid dissolved. The solution was gravity filtered to remove impurities. The filtrate was set aside to cool to room temperature and was set in an ice bath for complete recrystallization. The cooled mixture was suction filtered and was washed by two 2ml ice-cold toluene. The recrystallized tin tetraiodide was weighed and air-dried for a week. The air-dried crystal was weighed. The melting point range of the recrystallized tin tetraiodide was measured using a MEL-TEMP. Instruments should be washed by acetone during the experimental.
Result
Table 1 contains the molar mass, mass and the moles of reagents (Sn and I2) and products (crude SnI4, recrystallized SnI4 and air-dry SnI4). The yields of product and percent recover of