128 Wheeler and Pen field — Alkaline lodates. 



J RbCl . 2R10 % . — This compound, which is analogous to the 

 sodium compound 3NaCl . 2NaI0 3 . 9H 3 described by Ram- 

 melsberg* and also to the salt SISTal . 2NaI0 3 . 19H„0 obtained 

 by Pennyt or 3NaI . 2M0 3 . 20H„O according to Marignac4 

 except that it contains no water of crystallization, was prepared 

 by two methods. It was obtained by the addition of a hot, 

 strong aqueous solution of rubidium hydroxide to a strong 

 solution of iodide trichloride, the latter being in excess. The 

 mixture was then filtered hot and on cooling, a mass of fine 

 needles separated. The mother liquor on standing yielded the 

 large crystals of RbCl . HIO s . The needles are stable in the 

 air and at 100°. From the hot saturated aqueous solution of 

 the compound the normal iodate separates on cooling. 



The formation of this compound was also observed on add- 

 ing a strong solution of rubidium carbonate to a hot saturated 

 solution of RbCl . 01 3 I, the latter being in excess. The color- 

 less slender transparent needles thus obtained generally sepa- 

 rate in groups radiating from a point on the surface of the 

 yellow crystals of RbCl . C1 3 I. After separating the colorless 

 crystals mechanically from the pentahalide they were air-dried 

 on paper and then analyzed, while the material obtained accord- 

 ing to the previous method was dried at 100°. 



From RbOH From RboC0 3 Calculated for 



and IC1 3 . and RbCl . C1 S I. 3RbCl . 2HI0 3 . 



Rubidium, 35-41 34-58 35'78 35-87 



Iodine, 35-27 36*00 35-87 35-81 35-52 



Chlorine, 14-99 14-82 15-26 15-16 14-90 



Oxygen, 13-15 13-64 13-43 



Hydrogen, -29 -30 -28 



When heated, the substance does not decrepitate but melts, 

 gives off chloride of iodine and the residue consists of a mix- 

 ture of rubidium chloride and iodide. A sample of this resi- 

 due gave on analysis 9*68 per cent of chlorine and 38*91 per 

 cent of iodine. 



Normal Ccesium iodate CsI0 3 . — This was prepared by add- 

 ing a moderately strong aqueous solution of iodic acid to a 

 strong solution of caesium carbonate, care being taken to have 

 the carbonate in excess. "When all the iodic acid had been 

 added, the solution was boiled. On cooling, a crystalline mass 

 separated consisting apparently of small cubes. At 24°, 100 

 parts water dissolve 2*6 parts of the salt. It is insoluble in 

 alcohol. The body was prepared for analysis by filtering on 

 the pump, washing with cold water and then pressing on paper 

 and drying at 100°. 



* Pogg. Ann , xliv, 548 ; cxv, 584. 



f Ann. Ch. Pharra., xxxvii, 202. % Jahresb., 1857, 124: Ann. Min., V, ix, 1. 



