Chlorine, Bromine, Iodine and Astatine

Comment on “Stabilization of Low‐Valent Iron(I) in a High‐Valent Vanadium(V) Oxide Cluster”

“…= 6a nd g k ' = 2f rom the m s AE 1 / 2 Kramers doublet of the S = 5 / 2 system-known as an effective spin-1 / 2 .T he simulation provided gave an intrinsic g = 2.005, as mall zero-field splitting, D = 1.0 AE 0.2 cm À1 ,a nd negligible rhombicity (E/ D = 0.0015). In addition, hyperfine and quadrupolar coupling from the 35, 37 Cl (I = 3 / 2 ,1 00 %a bundant) was included to reproduce the lineshape profile at g k '.T he over-parameter- ization of the simulation reveals am isunderstanding of the origin in spin-Hamiltonian parameters and how they apply to defining electronic structure.M ost notably the inclusion of chlorine hyperfine and quadrupolar coupling is spurious given the very weak gyromagnetic ratios and small nuclear quadrupole moments of these isotopes.This contrasts other halides, [8] which have been shown to exhibit hyperfine structure in spectra of high-spin iron(III) complexes. [9,10] Secondly the sign and magnitude of D cannot be determined from an EPR spectrum of an S = 5 / 2 species in the weak field regime, [11] and should not be reported unless determined by another technique.T he covalent bonding in high-spin iron(III) complexes ensures j D j > hn,w ith values up to 10 cm À1 reported.…”

“…Thee lectronic spectrum is featureless in the visible region which is typical of ahigh-spin d 5 configuration. In addition, hyperfine and quadrupolar coupling from the 35, 37 Cl (I = 3 / 2 ,1 00 %a bundant) was included to reproduce the lineshape profile at g k '.T he over-parameter- ization of the simulation reveals am isunderstanding of the origin in spin-Hamiltonian parameters and how they apply to defining electronic structure.M ost notably the inclusion of chlorine hyperfine and quadrupolar coupling is spurious given the very weak gyromagnetic ratios and small nuclear quadrupole moments of these isotopes.This contrasts other halides, [8] which have been shown to exhibit hyperfine structure in spectra of high-spin iron(III) complexes. [7] TheEPR spectrum is typical of high-spin iron(III) with an axial profile defined with effective g-values of g ? '…”

BIOCHEMICAL DISPOSAL OF EXCESS H+IN GROWING PLANTS?

“…We compute the loss to the gas phase of HCl from a solution at pH 3-0 (1 mol H+ m~^) containing at least 1 mol Cl" m"^ (Rea, 1982) at 25 °C by using the values for HCl solubility in water at gas (HCl) pressure of 01 MPa tabulated by Downs & Adams (1973). These data suggest that a 1 mol m~^ HCl solution at 25 °C is in equilibrium with a gas phase containing 0-0366 mol HCl m^.…”

Kommentar zu “Stabilisierung eines niedrigvalenten Eisen(I)‐Ions in einem hochvalenten molekularen Vanadium(V)‐Oxid‐Cluster”

“…Diese Verbindung is eine von nur zwei bekannten eisenhaltigen Polyoxovanadaten, die andere verçffentlichte Verbindung basiert auf der bekannten Lindqvist-Struktur. Dies steht im Gegensatz zu anderen Halogeniden, [8] von denen gezeigt wurde, dass sie eine Hyperfeinstruktur in den Spektren von Highspin-Eisen(III)-Komplexen zeigen. Das elektronische Spektrum liegt im sichtbaren Bereich und zeigt keine besonderen Merkmale, was füre ine Highspin-d 5 -Konfiguration typisch ist.…”

“…Zum Beispiel ist das Einbeziehen von Chlor-Hyperfein-und Quadrupolkopplungen angesichts der sehr schwachen gyromagnetischen Verhältnisse und der kleinen Kernquadrupolmomente der Chlorisotope zweifelhaft. Dies steht im Gegensatz zu anderen Halogeniden, [8] von denen gezeigt wurde, dass sie eine Hyperfeinstruktur in den Spektren von Highspin-Eisen(III)-Komplexen zeigen. [9,10] Zweitens kçnnen Vorzeichen und Grçße von D nicht aus einem ESR-Spektrum einer S = 5 / 2 -Spezies im Schwachfeldregime bestimmt werden [11] und sollten nicht angegeben werden, sofern sie nicht durch eine andere Te chnik bestätigt wurden.…”