Synthesis and Characterization of Salts Containing the BrO<sub>3</sub>F<sub>2</sub><sup>-</sup> Anion; A Rare Example of a Bromine(VII) Species
Bibliographic record
Abstract
The BrO(3)F(2)(-) anion has been prepared by reaction of BrO(3)F with the fluoride ion donors KF, RbF, CsF, [N(CH(3))(4)][F], and NOF. The BrO(3)F(2)(-) anion is only the fourth Br(VII) species to have been isolated in macroscopic quantities, and it is one of only three oxide fluorides that possess D(3)(h)() symmetry, the others being XeO(3)F(2) and OsO(3)F(2). The fluoride ion acceptor properties of BrO(3)F contrast with those of ClO(3)F, which does not react with the strong fluoride ion donor [N(CH(3))(4)][F] to form the analogous ClO(3)F(2)(-) salt. The single-crystal X-ray structures of [NO](2)[BrO(3)F(2)][F] and [N(CH(3))(4)][BrO(3)F(2)] confirm the D(3)(h)() symmetry of the BrO(3)F(2)(-) anion and provide accurate Br-O (1.593(3)-1.610(6) A) and Br-F (1.849(5)-1.827(4) A) bond lengths. The salt, [NO](2)[BrO(3)F(2)][F], is fully ordered, crystallizing in the monoclinic space group, C2/c, with a = 9.892(3) A, b = 12.862(4) A, c = 10.141(4) A, beta = 90.75(2) degrees , V = 12460(7) A(3), Z = 4, and R(1) = 0.0671 at -173 degrees C, whereas [N(CH(3))(4))][BrO(3)F(2)] exhibits a 2-fold disorder of the anion, crystallizing in the tetragonal space group, P4/nmm, with a = 8.5718(7) A, c = 5.8117(6) A, V = 427.02(7) A(3), Z = 2, and R(1) = 0.0314 at -173 degrees C. The (19)F chemical shift of [N(CH(3))(4))][BrO(3)F(2)] in CH(3)CN is 237.0 ppm and is more deshielded than those of the previously investigated Br(VII) species, BrO(3)F and BrF(6)(+). The vibrational frequencies of the BrO(3)F(2)(-) anion were determined by use of Raman and infrared spectroscopy and were assigned with the aid of electronic structure calculations and by analogy with the vibrational assignments reported for XeO(3)F(2) and OsO(3)F(2). The internal and symmetry force constants of BrO(3)F(2)(-) were determined by use of general valence force field and B-matrix methods, respectively, and are compared with those of XeO(3)F(2), OsO(3)F(2), and the unknown ClO(3)F(2)(-) anion. The instability of ClO(3)F(2)(-) relative to BrO(3)F(2)(-) has been investigated by electronic structure calculations and rationalized in terms of atomic charges, Mayer bond orders, and Mayer valencies, and the enthalpies of fluoride ion attachment to BrO(3)F and ClO(3)F.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".