Thorium iodides

In the chemical process industry molybdenum has found use as washers and bolts to patch glass-lined vessels used in sulphuric acid and acid environments where nascent hydrogen is produced. Molybdenum thermocouples and valves have also been used in sulphuric acid applications, and molybdenum alloys have been used as reactor linings in plant used for the production of n-butyl chloride by reactions involving hydrochloric and sulphuric acids at temperatures in excess of 170°C. Miscellaneous applications where molybdenum has been used include the liquid phase Zircex hydrochlorination process, the Van Arkel Iodide process for zirconium production and the Metal Hydrides process for the production of super-pure thorium from thorium iodide. 

Thorium dioxide, 24 761-762 Thorium fluorides, 24 762 Thorium halides, 24 762-763 Thorium hydrides, 24 761 Thorium hydroxide, 24 756 Thorium iodides, 24 763 Thorium isotopes, 24 753-754... 

Thorium Iodide, Thorium tetraiodide. I4Th mol wt 739.69. I 68.63%, Th 31,37%. Thl4. Prepd hy passing iodine vapors in an inert gas over the metal at elevated temp Allen, Yost, J. Chem. Phys. 22, 855 (1954). See also Cuthbert, Thorium Production Technology (Addison-Wesley, Reading, Mass., 1958). 

Vin.4 Iodine compounds and complexes VIII.4.1 Solid and gaseous thorium iodides Vm.4.1.1 Thl2(cr), Thlj(cr)... 

VIII.4.2 Aqueous thorium iodine compounds VIII.4.2.1 Aqueous thorium iodide complexes... 

The compound was synthesised by reaction of thorium dioxide with a 20% excess molten thorium iodide. Most of the excess thorium iodide was subhmed from the product. Analytical results yielded 45.5% Th and 51.41% 1 (theoretical 46.2% Th and 50.6% I). The X-ray powder diffraction pattern was given but the data could not be indexed on the basis of a unit cell with orthorhombic or higher syimnetiy. 

A value of - (169.9 1.7) kJ-mol, the average of fom concordant measurements, was reported for the enthalpy of solution of the compound in 1 M HCl, after correction of individual measurements by 1.2 to 1.6 kJ-mol for the presence of 3 -5 wt% thorium iodide in the oxyiodide. The amount of this impurity was determined by analysis for thorium and iodine of individual calorimetric solutions. For this correction, the authors used a preliminary value of -314 kJ mol for the enthalpy of solution of Thl4(cr) in 1 M HCl. No further details on this value were given. 

The authors studied the thermal dissociation of thorium iodide mass-spectrometrically, and suggested that substantial decomposition to lower iodides and iodine vapour occurs when both the solid and liquid are heated. Coarse ciystals of Thl4(cr), prepared from the elements, were used to minimise the oxygen and water contents of the samples used in the (unspecified) Knudsen cell. The variation of the intensities of the TI1I4, TI1I3, TI1I2,12 and I ions observed in the mass-spectrometer was studied from ca. 625 to 800 K. 

A reactor is first out-gassed at 510°C and a pressure of 10 < mm of mercury, for a number of hours, with the crushed iodine present in a refrigerated side-tube. Thorium iodide is then allowed to form at 260°C and volatilized at about 450°C for the decomposition reaction. The filament temperature is maintained between 900°C and 1700°C, 1000°C being found satisfactory. 

Rubidium metal alloys with the other alkaU metals, the alkaline-earth metals, antimony, bismuth, gold, and mercury. Rubidium forms double haUde salts with antimony, bismuth, cadmium, cobalt, copper, iron, lead, manganese, mercury, nickel, thorium, and 2iac. These complexes are generally water iasoluble and not hygroscopic. The soluble mbidium compounds are acetate, bromide, carbonate, chloride, chromate, fluoride, formate, hydroxide, iodide. 

Comparable with the chloride system, complex ions of the form M2 ThX3] (A =Br [44490-064], M = (CH3) N, (C2H3) N X = I [44490-18-8], M = (C2H3) N, (CH3)3C3H3N) are known where the metal center is octahedral. Additional information on thorium bromides and iodides can be found in the hterature (81). 

Thorium carbide, ThC2, deposited from the iodide. 

Iodargyrite, natural occurrence of, 22 668 Iodates, 14 374-375 Iodate solutions, 14 362 Iodic acid, 14 375 Iodide analysis, of water, 26 41 Iodide ion, 14 367-368 25 488 Iodide-refining method, 26 149 for vanadium, 25 520 Iodides, 14 374 thorium, 24 763 tungsten, 25 379-380 uranium, 25 439... 

The Van Arkel process can also be used to prepare actinide metals if the starting compound reacts easily with the transporting agent (I2). The thorium and protactinium carbides react with I2 to give volatile iodides above 350°C these are unstable above 1200°C and decompose into the actinide metals and iodine. Attempts to prepare other actinides, such as U and Pu, through the process were not successful, because from Th to Pu along the actinide series, the vapour pressure of the iodide decreases and the thermal stability increases. 

The conductivities of thorium (III) and uranium (IV) halides in nitromethane are increased in the presence of a donor molecule from chloride to iodide and they also increase with increasing donicity of the neutral donor 49-53)... 

Proceeding from thorium to plutonium along the actinide series, the vapor pressure of the corresponding iodides decreases and the thermal stability of the iodides increases. The melting point of U metal is below 1475 K and for Np and Pu metals it is below 975 K. The thermal stabilities of the iodides of U, Np, and Pu below the melting points of the respective metals are too great to permit the preparation of these metals by the van Arkel-De Boer process. 

Thorium oxybromide, 1 54 Tin, as reducing agent for complex tungsten(VI) chlorides in preparation of complex potassium chlorotungstates(III), 6 149 Tin compounds, halomethyl derivatives, by the diazomethane method, 6 37 (CH8) 2 (CH2C1) SnCl, 6 41 Tin (IV) iodide, 4 119 Titanium, powder by reduction of titanium (IV) oxide with calcium, 6 47... 

---