Outer-sphere anion–anion charge transfer in a solid hexacyanoferrate

Anion−Anion Assembly in Crystal of Sodium Nitroprusside

“…In addition, EAS was successfully applied to ionic systems containing complex anion, e.g., hexacyanoferrate or ethylendiamintetraacetatocobaltate, 4 and one being the reducing agent such as I -, S 2 O 3 2-, and the like. The presence of additional charge transfer band in the corresponding spectra was found to be indicative of anion-anion association in the crystalline phase 5 as well as in aqueous solutions. 4 Along with the routine X-ray diffraction and EAS studies, the existence of interactions between the likely charged moieties has been also supported by IR spectroscopy 3 and NMR data.…”

Ion pairs in the crystal structure of potassium ethyl viologen hexacyanometallates(II)

“…The above crystallographic distances are much shorter than the distances between ions in the ion pair MV 2+ ,[Fe(CN) 6 ] 4estimated at 6.3-8.1 2 or 10.4 Å, 3 on the basis of the hexacyanoferrate ion radius 4.4-4.6 Å with respect to the fourfold axis of an octahedral complex. 2,3 Previously, 4,5 it was found that the effective radius of hexacyanoferrate ions with respect to the twofold axis of an octahedral complex, which is aligned with the direction of t 2g orbitals participating in electron † The compounds EV 1.5 K[M(CN) 6 ]•12.5H 2 O (M = Fe or Ru for 1 or 2, respectively) were isolated by the isothermal (T = 277 K) evaporation of solutions of ethyl viologen diiodide (Aldrich) and potassium hexacyanoferrate (analytical grade) or potassium hexacyanoruthenate (Alfa) in the 1:1 molar ratio. The intensities of 8227 reflections were measured within the range 1.55 < q < 28.01° (w/2q scan); 3356 independent reflections were used in the calculations (R int = 0.0911).…”

“…In the structures of 1 and 2, [M(CN) 6 ] 4ions exhibit C 3 symmetry. The geometry parameters of two crystallographically independent cyanide ligands differ from one another [C(1)-N(1) 1.149 (5) in an increase in the number of active n CN vibrations in the IR spectra (Figure 5). ¶ The free [M(CN) 6 ] 4ion having O h symmetry should exhibit only a single n CN band due to threefold degenerate F 1u vibrations.…”