Tin. This is Tin. Uses. Name tin comes from the Anglo-Saxon word "tin" meaning tin. The symbol Sn comes from the latin word stannum meaning.

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1 This is Tin Tin Colour: silvery grey Classification: Metallic Atomic number: 50 Atomic weight: Name tin comes from the Anglo-Saxon word "tin" meaning tin. The symbol Sn comes from the latin word stannum meaning. Uses Used to coat other metals to prevent corrosion or other chemical action (tin cans are tin coated steel) Some window glass is made by floating molten glass on molten tin (float glass) to produce a flat surface 1

2 Nanocrystalline Tin as a Preparative Tool: Synthesis of Unprotected Nanoparticles of SnTe and SnSe and New Route to (PhSe) 4 Sn Sabine Schlecht, Michael Budde, And Lorenz Kienle Presented by Andrew Ritchie This paper presents a new method for making tin calcogenide nanoparticles from nanocrysatlline-activated tin metal. Similar techniques have been used for the synthesis of II/VI semiconductor nanoparticles, but not for IV/VI semiconductor nanoparticles. Elemental reaction Semiconducting compounds such as SnSe and SnTe are used in IR detectors and thermoelectric materials. It is thought that SnS may be used as a photoactive layer in solar cells. Only a few methods for the production of IV/VI semiconductor nanoparticles exist while many exist for the synthesis of II/VI semiconductor nanoparticles. Nanocrystalline tin was formed for all reactions by dissolving SnCl 2 in THF and reducing it at room temperature with Li[ET 3 BH] Elemental nanocrystalline tin was reacted with selenium at 125 o C for 24 hours Elemental nanocrystalline tin was reacted with tellurium at 85 o C for 24 hours 2

3 Synthesis of SnTe Nanoparticles Conditions A 1.0 mmol of nanocrystalline tin metal was suspended in 60 ml of anhydrous diglyme. 1.0 mmol of diphenyl ditelluride was dissolved in this The suspension was heated at 165 o C for 2 hours then allowed to cool to room temperature before the nanoparticles were vacuum dried Synthesis of SnSe Nanocrystals Sn(SePh) 4 was made by suspending 1.0 mmol of activated tin in 50 ml of tetrahydrofuran (THF), adding 2.0 mmol of diphenyl diselenide and refluxing for 15 hours A small amount of residual tin was filtered off and the solvent was evapourated to dryness SnSe nanocrystals were then produced by heating the Sn(SePh) 4 at 300 o C for half an hour Conditions B The same was done with.1 mmol of nanocrystalline tin and.1 mmol Ph 2 Te 2 1 mmol of nanocrystalline tin and 1 mmol of Ph 2 Se 2 were reacted under the same conditions as well. The reaction with diphenyl diselenide produced microcrystals instead of nanocrystals Results The elemental reactions formed the desired products SnSe and SnTe The products were microcrystalline and not nanocrystalline 3

4 SnTe nanoparticles were formed from nanocrystalline tin under conditions A and conditions B It was expected that the change in concentration of SnCl 2 would have an effect on the size of the elemental tin nanoparticles Particle size of the nanocrystalline tin was not affected by the concentration of the SnCl 2 used in its production The tin telluride nanocrystal size was dependant on the concentrations of the elemental tin and Ph 2 Te 2 used Micrograph of star shaped agglomerates of SnTe needles produced under conditions B Average size of nm Micrograph of round SnTe nanocrystals produced under conditions A Average particle size of 60 nm Two steps had to be performed to make SnSe nanocrystals One part Nanocrystalline tin reacted with two parts diphenyl diselenide at 65 o Cfor 15 hours to give Sn(SePh) 4 A 94% yield was obtained by this method of synthesis compared to a 60% yield obtained in Sn(SePh) 4 s classic synthesis 4

5 Summary Heating at 300 o C for half an hour then produced SnSe nanoparticels The SnSe nanoparticels were not as uniform in size as the SnTe particles, ranging in size from 3 to 50 nm When the Sn(SePh) 4 heated for too long, large masses of SnSe were formed that were not nanocrystalline Activated nanocrystalline tin can be used to prepare tin calcogenide nanoparticles SnTe particle size and shape are dependant on the concentration of reactants A new more efficient rout for synthesis of Sn(SePh) 4 has been found References Both types of crystals were analysed with a High resolution electron microscope, selected area electron diffraction, and x- ray difraction Analysis of SnSe and SnTe crystals showed that there was a 1:1 ratio in both Analysis of SnTe crystals showed that both round and needle were highly crystalline and had very few defects Schlecht, S.; Budde, M.;Kienle, L.Inorg. Chem, 2002, 41,