182 



Wheeler and Pen-field — Alkaline Iodates. 



This compound and the one obtained by Marignac are there- 

 fore identical. 



On ignition it gives off water, iodine chloride and oxygen, 

 the residue consisting of potassium iodide and chloride. An 

 analysis of this residue gave 2*39 per cent, chlorine and 70*87 

 per cent, iodine. 



The author takes occasion here to express his obligations to 

 Professor H. L. Wells for the use of the material in this in- 

 vestigation and for valuable suggestions, also to Professor S. 

 L. Penfield who has kindly furnished the crystal lographical 

 descriptions. 



Notes on the Crystalline form of lib CI . HIO^ 

 ' H10 % ; byS. L. Penfield. 



RbCl . HIO.. 



and CsCl . 



^^7 



The form of RbCl . HI0 3 is monoclinic. The 

 crystals are highly modified, doubly termi- 

 nated prisms, fig. 1. The faces gave fair reflec- 

 tions and the measurements which were chosen 

 as fundamental are marked by an asterisk in 

 the table of angles. 



The axial ratio and forms are as follows: 



a : b : <■ = 0-9330 : 1 : 1511, /3 = 100 a 001 = 87° 56' 



a, 100, i-l ?, 320, «"-"| d,0U,\-% g, l02,.£-! q, 142, —2-4 



6, 010, U m, 110, I e, 101, — 1-i o, 211, —2-2 s, 211, 2-2 



c, 001, n, 120, «-2 /, 101, \-l p, 111, — 1 u, 111, 1. 



Measured. Calculated. 



a a c, 

 a a e, 

 c a d, 

 a a I, 

 a a m, 

 a a n, 

 a a o. 

 a a p, 



100 a 001 =*87 



100a101=*51 5 



001a011=*37 8 



100 a 320 =33 13 



100 a 110 = 44 1 



100 a 120 = 62 42 



100a2U = 38 19 



100 a 111 = 57 13 



6' 



33° 13' 



44 291 

 63 U 

 38 28-| 



57 14" 



Measured. Calculated. 

 a*d, 100 a Oil = 88° 29 88° 21' 

 a a s, 100 a 211 = 38 32 39 47 

 a~u, 100 a 111 =59 57 59 38 

 e ~p, ]01 a 111 = 30 28 30 31 

 /am, 101a 111 =31 22£ 31 24 

 p^q, 111 a 142 = 26 36 26 30 

 c ~g. 001 a 102 = 21 17 21 20 

 c a f, 001 a 101 = 38 26 38 23£ 



CsCl . HIO, 



The form of CsCl . HI0 3 is monoclinic. The crystals, from 

 9 the one crop which was examined, were 



about 5 mm. in length and had the 

 habit shown in fig. 2. They were 

 attached at one end and usually grew 

 in radiating and divergent groups. The 

 faces were not very perfect and only approximate measure- 



