An Accidental Discovery of a New Mixed-Valent Iodine Compound − Crystal Structure of Difluoroiodato(V) Iodine(III) Dichloride [Cl2IOI(O)F2]

Abstract

The crystal structure of the novel iodine compound Cl2IOI(O)F2 is described. Cl2IOI(O)F2 contains iodine in two different oxidation states (III) and (V) and can formally be described as ICl2+IF2O2−, linked by an unsymmetrical, nonlinear I−O−I bridge, with I−O bond lengths of 1.84(1) Å and 2.32(1) Å, and a bond angle of 122.5(5)°. It was accidentally obtained by the uncontrolled reaction between CF3I, CF3OCl, CF2O, and Cl2 at −70 °C over a period of about six months and finally two days at room temperature. Cl2IOI(O)F2 crystallises in the monoclinic space group P21/c with four formula units per unit cell with the dimensions a = 12.910(1), b = 6.987(1), c = 7.550(1) Å, and β = 94.890(1)°. The molecule was additionally characterised by its Raman and IR spectra.

K6(IO6H4)(HI2O6)(HIO3)2(IO3)4·2H2O: A Case of Iodate with Coexisting [I5+O3] and [I7+O6] Units

“…The I 5+ valence state is the one class with a high proportion (79.29%, 448), whereas the I 7+ valence state is followed by 17.17% (97). The mixed-valence states are discovered in the following 11 iodates: I­(OSO 2 F) 2 I (−1 and +3; Figure S5a), Ag 3 I­((MoO 3 ) 2 (IO 3 ) 2 ), Ag 9 I 3 (SeO 4 ) 2 (IO 3 ) 2 , Bi 3 (IO 3 ) 12 (Ag 4 I) (−1 and +5; Figure S5b–d), ((Cl 2 I)­OIO)­F 2 , (I 3 O 6 )­(HSO 4 ) (+3 and +5; Figure S6a,b), (IOF 2 )­(IO 2 F 4 ), I 4 O 12 , Th­(H 2 O)­(IO 3 ) 2 (I 0.6 V 1.76 O 7 (OH)), Bi 2 (IO 3 )­(IO 6 ) (+5 and +7; Figure S7a–d), and the title compound (+5 and +7).…”

“…), ((Cl 2 I)OIO)F 2 ,45 (I 3 O 6 )(HSO 4 )46 (+3 and +5; FigureS6a,b), (IOF 2 )(IO 2 F 4 ),30 I 4 O 12 , 31 Th(H 2 O)-(IO 3 ) 2 (I 0.6 V 1.76 O 7 (OH)), 32 Bi 2 (IO 3 )(IO 6 ) 33 (+5 and +7; Figure S7a−d), and the title compound (+5 and +7).…”

8 Halogens and noble gases

“…However, an accidental discovery led to Cl 2 IOI(O)F 2 , the first example of an iodine oxofluoride chloride with mixed valency iodine atoms. 27 The structure of this serendipitous compound is of two linked trigonal bipyramidal iodine centres, one formally ϩ the other ϩ, linked by an oxygen bridge. A distorted bipyramidal structure has also been reported for CF 3 IClF, the only known example of a ternary interhalogen compound containing a CF 3 group, and formally a derivative of the unknown interhalogen IF 2 Cl.…”