The relative sizes of the Cr(III), Mn(III), Fe(III), and Co(III) ions in low-spin octahedral complexes

Chadwick, B. M.; Sharpe, A. G.

doi:10.1039/j19660001390

Cited by 18 publications

(12 citation statements)

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“…a Numbers in parentheses in all tables and in the text are estimated standard deviations occurring in the least significant digit of the parameter. 6 An asterisk denotes a parameter fixed by symmetry. c B's are isotropic thermal parameters equivalent to the anisotropic tensors: W. C. Hamilton, Acia Crystallogr., 12, 609 (1959).…”

Section: Methodsmentioning

confidence: 99%

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Crystal structure of 4-methylpyridinium nonabromoantimonate(V), (4-C6H7NH)2SbVBr9

Lawton¹,

Hoh²,

Johnson³

et al. 1973

Inorg. Chem.

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4-Methylpyridinium nonabromoantimonate(V), (C6H7NH)2SbvBrg, crystallizes as deep red acicular crystals in the monoclinic space group C2/m (C2h3) with unit cell parameters a = 18.39 (1), b = 7.440 (4), c = 9.84 (1) A, and ß = 113.14 (6)°. The observed and calculated densities are 2.64 and 2,760 (7) g/cm3, respectively. The structure was refined by leastsquares methods to a conventional discrepancy index of 0.050 using three-dimensional X-ray diffraction counter data. The structure is comprised of 4-methylpyridinium, SbvBr6", and Br3~ions, the packing of which is similar to that in 2-methylpyridinium nonabromoantimonate(V). The SbBr6" ion possesses crystallographic C2y¡ symmetry and has an average bond length of 2.563 (4) A. The tribromide ion is centrosymmetric with a bond length of 2.561 (4) A. These two ions form nearly linear chains displaying bromine • • • bromine contacts of 3.444 (4) A. The shortest hydrogen • • • bromine separation, 2.9 (1) A, involves the V-H proton of the cation with the SbBr6" anion.to the additional presence of intervalent electron-transfer absorption bands. Those having composition (RH+)2 -(SbvBr6~)(Br3~), however, become variably colored at -196°( the temperature of liquid nitrogen10). Upon cooling, their intense colors disappear, first changing from black to violet (reference here being to reflected light11), then progressively to red, red-orange, and orange, depending upon RH+ and hence structure. This progression of color change is consistent with a sharpening of absorption bands in the near-ultraviolet region whose edges overlap the blue end of the visible spectrum. As is shown by Table I for a series of these salts, the higher the temperature at which the color change starts to occur for a given material the more orange it becomes at -196°. The different colors at any given temperature depend primarily on how far into the visible region the absorption bands extend before tailing off. This has been demonstrated for the 2-methylpyridinium and quinolinium salts by diffuse reflectance spectroscopy;12 spectra of these (1) Research carried out during the spring of 1971 by special permission of Mobil Research and Development Corp.(2) Mobil Research and Development Corp.(3) (a) Senior,

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Section: Methodsmentioning

confidence: 99%

“…0 Uncorrected for thermal or librational effects. 6 Dimensions of the pyridinium ring appear in footnote 28. c Br(2a) occurs at x,y, z. square thermal displacements along the directions of the principal axes for those atoms refined aniso tropically are given in Table III.…”

Section: Methodsmentioning

confidence: 99%

Crystal structure of 4-methylpyridinium nonabromoantimonate(V), (4-C6H7NH)2SbVBr9

Lawton¹,

Hoh²,

Johnson³

et al. 1973

Inorg. Chem.

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“…Aside from Mn-III-BCF, Mn-III-246, and Cr-II-BCF (non-Kramers ions), all C-term intensities exhibited linear dependences on inverse temperature from 5 to 20 K. Peak maxima, MCD signs, and transition assignments are given in Table 8. MCD behavior is more complex for higher ground-state spin multiplicities, so we restrict detailed analyses to (t2g) 5 complexes, and provide only tentative assignments for (t2g) 4 and (t2g) 3 systems.…”

Section: Intensities Can Be Estimated Frommentioning

confidence: 99%

“…(t2g) 4 Complexes The (t2g) 4 electronic configuration is complicated by its non-Kramers ( 3 T1g) ground term. Firstorder spin-orbit coupling splits out a nondegenerate ground state (𝐴 1𝑔 ′ ) with a 𝑇 1𝑔 ′ state approximately 100 cm −1 higher in energy.…”

Section: Intensities Can Be Estimated Frommentioning

confidence: 99%

“…3 Most metal cyanide complexes are traditionally prepared from the reaction of alkali cyanides with metal chloride salts at elevated temperatures. 3,4 Oxidized versions of cyanometallates are typically prepared using reduced forms and a suitable oxidant. [5][6][7][8] Coordination numbers of metal cyanides vary substantially throughout the d-block.…”

Section: Introductionmentioning

confidence: 99%

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Boronated Cyanometallates

McNicholas,

Nie,

Jose

et al. 2022

Preprint

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Fourteen boronated cyanometallates ([M(CN-BR3)6]3/4/5– (M = Cr, Mn, Fe, Ru, Os, R = BPh3, B(2,4,6,-F3C6H2)3, B(C6F5)3) have been characterized by X-ray crystallography and spectroscopy [UV-vis-NIR, NMR, IR, spectroelectrochemistry, and magnetic circular dichroism (MCD)]; CASSCF+NEVPT2 methods were employed in calculations of electronic structures. For (t2g)5 electronic configurations, the lowest energy ligand-to-metal charge transfer (LMCT) absorptions and MCD C terms in the spectra of boronated species have been assigned to transitions from cyanide σ+π + B-C borane σ orbitals. CASSCF+NEVPT2 calculations including t1u and t2u orbitals reproduced t1u/t2u → t2g excitation energies. All ([M(CN-BR3)6]3/4− complexes exhibited highly electrochemically reversible redox couples. Notably, the formal potentials of all five [M(CN-B(C6F5)3)6]3− anions scale with LMCT energies; and Mn(I) and Cr(II) compounds, (K(18-crown-6))5[Mn(CN-B(C6F5)3)6] and (TBA)4[Cr(CN-B(C6F5)3)6], are surprisingly stable. Continuous wave and pulsed electron paramagnetic resonance (hyperfine sublevel correlation) spectra were collected for all Cr(III) complexes; as expected, 14N hyperfine splittings are greater for (TBA)3[Cr(NC-BPh3)6] than for (TBA)3[Cr(CN-BPh3)6]. Using (TBA)4[Fe(CN-B(C6F5)3)6] and (TBA)3[Fe(CN)6], a model flow battery was constructed and found to have an 80% energy effi-ciency.

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Raman scattering and phase transition in orthorhombic crystals of K₃Mn(CN)₆ and K₃Cr(CN)₆

Morioka

Saitô

Nakagawa

1989

J Raman Spectroscopy

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In the polarized Raman spectra of K,Mn(CN), and K,Cr(CN),, soft modes are observed in both the roomtemperature and the low-temperature phases. The frequencies of these modes decrease as the transition temperatures I205 K for K,Mn(CN), and 215 K for K,Cr(CN),] are approached from both sides. Unambiguous spectroscopic evidence for the second-order displacive phase transition was obtained on the basis of the soft mode behaviour in both crystals. High-pressure Raman spectra of K,Cr(CN), were measured up to 35 kbar using a diamond anvil cell. A pressure-induced phase transition occurs at ca 10 kbar.

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The relative sizes of the Cr(III), Mn(III), Fe(III), and Co(III) ions in low-spin octahedral complexes

Cited by 18 publications

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Crystal structure of 4-methylpyridinium nonabromoantimonate(V), (4-C6H7NH)2SbVBr9

Crystal structure of 4-methylpyridinium nonabromoantimonate(V), (4-C6H7NH)2SbVBr9

Boronated Cyanometallates

Raman scattering and phase transition in orthorhombic crystals of K₃Mn(CN)₆ and K₃Cr(CN)₆

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The relative sizes of the Cr(III), Mn(III), Fe(III), and Co(III) ions in low-spin octahedral complexes

Cited by 18 publications

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Crystal structure of 4-methylpyridinium nonabromoantimonate(V), (4-C6H7NH)2SbVBr9

Crystal structure of 4-methylpyridinium nonabromoantimonate(V), (4-C6H7NH)2SbVBr9

Boronated Cyanometallates

Raman scattering and phase transition in orthorhombic crystals of K3Mn(CN)6 and K3Cr(CN)6

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Raman scattering and phase transition in orthorhombic crystals of K₃Mn(CN)₆ and K₃Cr(CN)₆