Thallous fluoride

Treatment of 3-deoxy-l,2 5,6-di-0-isopropylidene-a-D-erythro-hex-3-enofuranose with iodine and thallous fluoride in anhydrous ether afforded227 3-deoxy-l-fluoro-3-iodo-l,2 5,6-di-0-isopropyli-dene-D-xy/o-4-hexulose in 80% yield, together with small proportions of (tentatively identified) 3-deoxy-4-fluoro-3-iodo-l,2 5,6-di-0-iso-propylidene-a-D-allofuranose and two unidentified products. A mechanism proposed for the furanose ring-opening involves the formation of a 3,4-iodonium ion, and attack by fluoride at C-l. 

T1F (c). There are no data on the heat of solution of thallous fluoride. 

Thallous ferrifluoride, 8TlF.2FeF3, is obtained as pink crystals on evaporating a solution of thallous fluoride and excess of ferric fluoride.9... 

F. Ephraim and F. Barteezko prepared thaUous chromium enneafluoride, 3TlF.2CrF3, by evaporating a mixed soln. of chromic and thallous fluorides. It forms a green, crystalline powder. 

Thallo-. thallous, thalhum(I). -bromid, a, thallous bromide, thalliuro(I) bromide -chlorat, n. thallous chlorate, thallium(I) chlorate, -chlorid, n. thallous chloride, thallium I) chloride, -fluorid, n. thallous fiuoride. thal lium(I) fiuoride. -ion, n- thallous ion, thal lium(I) ion. -jodat, n. thallous iodate. thal liura(I) iodate. -jodid, n. thallous iodide. thallium(I) iodide, -salz, n. thallous salt. thallium(I) salt, -sulfat, n. thallous aulfate. thailium(I) sulfate, -verbindung, /. thallous compound, thallium(I) compound. 

Thallous halides offer a unique possibility of studying the stereochemistry of the (chemically) inert electron pair, since their structures and their pressure and temperature-dependent phase transitions have been well established. Thallium (1) fluoride under ambient conditions, adopts an orthorhombic structure in the space group Pbcm which can be regarded as a distorted rocksalt structure (Fig. 2.4). In contrast to TIF, the thallium halides with heavier halogens, TlCl, TlBr and Til, adopt the highly symmetric cubic CsCl structure type under ambient conditions [46]. Both TlCl and TlBr, at lower temperatures, undergo phase transitions to the NaCl type of structure [47]. 

Unlike boron, aluminum, gallium, and indium, thallium exists in both stable univalent (thallous) and trivalent (thallic) forms. There are numerous thallous compounds, which are usually more stable than the corresponding thallic compounds. The thallium(I) ion resembles the alkali metal ions and the silver ion in properties. In this respect, it forms a soluble, strongly basic hydroxide and a soluble carbonate, oxide, and cyanide like the alkali metal ions. However, like the silver ion, it forms a very soluble fluoride, but the other halides are insoluble. Thallium(III) ion resembles aluminum, gallium, and indium ions in properties. 

Thallous ethoxide added all at once with stirring to 1.1 moles acetylacetone in petroleum ether, stirring continued 2-3 min., chilled and filtered acetylaceto-natothallium(I) (Y ca. 100%) suspended in methyl iodide, stirred and refluxed 4 hrs. -> 3-methylpentane-2,4-dione (Y ca. 100%). - This synthesis proceeds cleanly without any side reactions. F. e., also G-acetylation with acetyl fluoride and 0-acelylation with acetyl chloride, s. E. C. Taylor, G. H. Hawks, III, and A. McKillop, Am. Soc. 90, 2421 (1968). 

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