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TIN Natural Abundance, Stable Isobars Sn112, 0.95%, Cd112 Sn114, 0.65%, Cd114 Sn115, 0.34%, Cd116 Sn116, 14.24%, aIn115 Sn117, 7.57%, Te120 Sn118, 24.01%, Te122 Sn119, 8.58%, Te124 Sn120, 32.97%, Xe124 Sn122, 4.71% Sn124, 5.98% Tin dichloride and tin tetrachloride have been used in the separation of the isotopes of tin. The liquid SnCl4 is the preferred charge and is supplied to the calutron from an externally located style SE stainless steel charge bottle containing 1,000 g SnCl4 . Tin tetrachloride is prepared in the laboratory by reacting mossy tin metal with chlorine gas under quenched conditions in which SnCl4 acts as the quenching agent. The reactor consists of a 5 cm Pyrex tube 2 m long mounted vertically and having its lower end drawn down to 1.5 cm. A gas feed side-arm is located 7.5 cm above the constriction and is connected by Tygon hose to a cylinder of chlorine. A gravity leg consisting of a 1.5 m length of 0.5 cm Tygon tubing is attached to the lower end of the reactor using a hose clamp. A carbon disk 1.5-cm thick and of a size to fit snugly inside the reactor tube at the constriction is drilled with 20, 0.5-cm holes. This grate allows the liquid SnCl4 to drain from the reactor but confines the solid tin metal above the gas inlet tube. After placing the grate in position, the reactor is two-thirds filled with mossy tin metal. Liquid SnCl4, from a previous synthesis, is added to the reactor until the liquid level is at least 2 in. above the gas inlet side-arm. This quench of liquid SnCl4 is necessary to dissipate the heat of reaction, otherwise localized heating would melt the tin and allow it to fall through the grate. Even with the quench solution, the flow of chlorine must be carefully adjusted to prevent melting of the tin metal. A one-hole rubber stopper fitted with a short piece of glass tubing is placed in the upper end of the reactor, and unreacted chlorine is conducted to a fume hood through an attached length of Tygon tubing. As the reaction of chlorine with tin continues, SnCl4 accumulates in the reactor causing liquid level to rise. When the liquid level has risen by about 30 cm, removal to a storage container is effected by lowering the free end of the gravity leg. Thus the liquid in the reactor is returned periodically to its initial level as the reaction product is drawn off. Since tin can be added to the reactor as needed, and the product can be removed periodically, the process is essentially continuous. Tin chloride vapors are irritating to the eyes and cause some intoxication. This compound hydrolyzes upon contact with moisture to form hydrogen chloride which is also corrosive and poisonous. Adequate ventilation plus the use of protective equipment including rubber gloves, safety goggles, and an adequate respirator should eliminate the hazards of working with this compound. aIn115, natural abundance 95.77%, is radioactive with a half-life of 6 × 1014 years. |
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