Sodium iodine(V) oxyfluoride, NaIO₂F₂

Abstract

As an extension of a general structural study concerning fluorides and oxyfluorides of cations presenting a stereochemically active electronic lone pair, until now limited to tellurium(IV) phases, the previously unknown structure of NaIO(2)F(2) corresponds to a new structure type based on isolated IO(2)F(2)(-) polyhedra forming sheets separated by Na(+) layers. The sodium ion is octahedrally coordinated with 2/m site symmetry, while the I(V) atom has m2m symmetry with a stereochemically active lone electron pair. The O and F atoms (both with m symmetry) are bonded to the I(V) atoms in a fully ordered manner. A comparison with the structure of ferroelastic KIO(2)F(2) and with structures based on hexagonal close packing of anions, mainly rutile-type and FeTeO(3)F-type, reveals differences that are attributed to the smaller ionic radius of Na(+) and the ordering of the Na and I cations.

New Alkaline-Earth Metal Fluoroiodates Exhibiting Large Birefringence and Short Ultraviolet Cutoff Edge with Highly Polarizable (IO3F)2– Units

“…The introduction of fluorine into iodate systems has been focused recently. The fabulous NLO performances of fluorine-containing iodates, such as Bi 3 OF 3 (IO 3 ) 4 , Bi­(IO 3 )­F 2 , ABi 2 (IO 3 ) 2 F 5 (A = K, Rb, and Cs), α- and β-Ba 2 [GaF 4 (IO 3 ) 2 ]­(IO 3 ), α- and β-Ba­[VFO 2 (IO 3 ) 2 ], α- and β-Ba 2 [VO 2 F 2 (IO 3 ) 2 ]­IO 3 , Ce­(IO 3 ) 2 F 2 ·H 2 O, K 5 (W 3 O 9 F 4 )­(IO 3 ), (NH 4 )­Bi 2 (IO 3 ) 2 F 5 , and MIO 2 F 2 ,,, (M = Na, K, Rb, Cs) have been proven, but their potentials in birefringent applications are still seldom exploited. Generally, on the basis of different connection modes between I, O, and F atoms, the fluorine iodates can be divided into two categories: (1) iodate fluorides can form M–F bonds, such as Bi­(IO 3 )­F 2 and (2) fluoroiodates can form I–F bonds, such as RbIO 2 F 2 and CsIO 2 F 2 . , The structurally characterized fluoroiodates all display very simple structures with isolated (IO 2 F 2 ) − , (IOF 4 ) − , or (IO 2 F 4 ) 3– . , In addition, according to Table S11, almost 83% of the reported fluoroiodates are constructed by the (IO 2 F 2 ) − groups.…”

Reactions of ClF3 with Main Group and Transition Metal Oxides: Access to Dioxychloronium(V) Fluoridometallates and Oxidofluoridometallates

“…Salts containing disphenoidal (seesaw) C 2 v [ X O 2 F 2 ] − anions are also known but they are usually not formed by the direct reaction of X O 2 F with a fluoride ion donor [46–49] . Thus far, only salts with [IO 2 F 2 ] − anions have been structurally characterized by single‐crystal X‐ray diffraction [49–52] . For Cl, the direct reaction of ClO 2 F with CsF, yielding Cs[ClO 2 F 2 ], is known, and for Br, the reaction of BrO 2 F with KF, giving K[BrO 2 F 2 ], accompanied with the partial decomposition of BrO 2 F during this reaction, has been reported [47,48,53] .…”

“…[46][47][48][49] Thus far, only salts with [IO 2 F 2 ] À anions have been structurally characterized by single-crystal X-ray diffraction. [49][50][51][52] For Cl, the direct reaction of ClO 2 F with CsF, yielding Cs[ClO 2 F 2 ], is known, and for Br, the reaction of BrO 2 F with KF, giving K[BrO 2 F 2 ], accompanied with the partial decomposition of BrO 2 F during this reaction, has been reported. [47,48,53] The indirect formation via hydrolysis reactions of K[BrF 6 ] or fluorination of K[BrO 3 ] with BrF 5 is also possible, but K[BrOF 4 ] is usually also formed.…”

Halogens and noble gases

“…The crystal structure of NaIO 2 F 2 , an oxyfluoride of a cation presenting a stereochemically active lone pair, has also been reported. 43 Two reports concern the oxidation of biomolecules with ClO 2 a highly reactive, but stable free radical. The stereochemistry, kinetics and mechanism of the oxidation of dihydronicotinamide adenine dinucleotide (NADH) with ClO 2 was explored to probe the nature of the oxidation pathway-hydride transfer or a variation of a single-electron transfer process.…”