Analysis of Ground-state Zero-field Splitting for Mn²⁺ Ions in [Co(H₂O)]XY₆ (X=Si, Sn, Pt; Y=F, Cl)

Abstract

The electron paramagnetic spectra of trigonal Mn²⁺ centers in [Co(H₂O)₆]SiF₆, [Co(H₂O)₆] SnF₆, and [Co(H₂O)₆]PtCl₆ crystals were studied on the basis of the complete energy matrices for a d⁵ configuration ion in a trigonal ligand field. When Mn²⁺ is doped in the [Co(H₂O)₆]SiF₆, [Co(H₂O)₆]SnF₆, and [Co(H₂O)₆]PtCl₆ crystals crystals, there is a similar local distortion. The experimental results show that the local lattice structure around a trigonal Mn²⁺ center has an elongation distortion along the crystalline C₃ axis. From the EPR calculation, the local lattice structure parameters R=2.278A, θ=52.6406° for [Co(H₂O)₆]SiF₆, R=2.280, θ=52.4936° for [Co(H₂O)₆]SnF₆ and R=2.244A, θ=53.0616° for [Co(H₂O)₆]PtCl₆ were determined.

Keywords

[Co(H₂O)₆]SiF₆ / [Co(H₂O)₆]SnF₆ and [Co(H₂O)₆]PtCl₆ / local lattice structure distortion / EPR spectrum / ligand-fields theory

References

[1] Jeschke G. Structure Characterization of the Copper(II) Complex of Poly(4-vinylpyridine) by a Combination of EPR, ENDOR, and Molecular Modeling Techniques[J]. J. Phys. Chem. B, 2000, 104: 8 382-8 390.

[2] Mantel C, Baffert C, Romero I, Deronzier A, Pecaut J, Collomb MN, Duboc C. Structural Characterization and Electronic Properties Determination by High-field and High-frequency EPR of a Series of Five-coordinated Mn (II) Complexes[J]. Inorg. Chem., 2004, 43: 6 455-6 463.

[3] Dasgupta J, Tyryshkin AM, Kozlov YN, Klimov VV, Dismukes GC. Carbonate Complexation of Mn²⁺ in the Aqueous Phase: Redox Behavior and Ligand Binding Modes by Electrochemistry and EPR Spectroscopy[J]. J. Phys.Chem. B, 2006, 110: 5 099-5 111.

[4] Zong X H, et al. Effect of pH and Copper(II) on the Conformation Transitions of Silk Fibroin Based on EPR, NMR, and Raman Spectroscopy[J]. Biochemistry, 2004, 43: 11 932-11 941.

[5] Wan K L, Hutton Stuart L, John E. Drumheller. Temperature Dependence of the EPR Zero-field Splitting of Mn²⁺ in ZnSiF₆-6H₂O[J]. J. Chem. Phys., 1987, 86: 3 801-3 812.

[6] Misra SK, Stefan D, Dmitry T, Freed J H. A Multifrequency EPR Study of Fe²⁺ and Mn²⁺ Ions in a ZnSiF₆·6H₂O Single Crystal at Liquid-helium Temperatures[J]. Journal of Magnetic Resonance, 2010, 205: 14-22.

[7] Zheng WC, Wu SY. Local Structure and Local Compressibilities Around Co²⁺ Impurity in ZnSiF₆ ^·6H₂O Crystal Determined from Electron Paramagnetic Resonance Data[J]. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2001, 57: 1 177-1 182.

[8] Rubins RS. Temperature Dependence of the Zero-field Splitting of Ni²⁺ in ZnSiF₆ · 6H₂O and ZnSiF₆ · 6D₂O at Low Temperatures[J]. J. Chem. Phys., 1986, 84: 4 142-4 150.

[9] Zapart W. High-Temperature Phase of MgSiF₆· 6H₂O by EPR of Manganese Ions[J]. J. Phys. Chem. B, 2003, 107(17): 4 208-4 212.

[10] Roy SKD, Pal A, Ghosh B, Chatterjee N, Das AN. Effect of Pressure on the Structural Phase Transition Temperature in CoSiF₆.6H₂O and CoZrF₆.6H₂O[J]. Journal of Physics C: Solid State Physics, 1977, 10: L403-410.

[11] Chattopadhyay T, Devreux F, Peters K, Peters E-M, Gmelin E, Ghosh B. Crystal Structure and Phase Transitions in MnTiF₆.6H₂O and ZnTiF₆.6H₂O[J]. Journal of Physics C: Solid State Physics, 1988, 21: 1 321-1 329.

[12] Hrabański R. Epr of Mn²⁺-doped Single Crytals of [Co(H,O),]XY, (X = Si, Sn, Pt; Y = F, Cl)[J]. Chemical Physis Letters, 1986, 123(3): 182-186.

[13] Hrabański R. EPR of Mn²⁺ in [Co(H₂O)₆] PtCl₆, Single Crystals: Estimation of Co²⁺ Spin-lattice Relaxation Time[J]. Spectrochimica Acta, 1988, 44A: 647-650.

[14] Jain VK. Superposition Model Analysis for the Zero-field Splitting of Mn²⁺ in Some Crystals[J]. Modern Physics Letters B, 2006, 20: 1917-1920.

[15] Abragarn A, Bleaney B. Electron Paramagnetic Resonance of Transition Ions[M], 1970 Clarendon: Oxford.

[16] Stevens KWH. Matrix Elements and Operator Equivalents Connected with the Magnetic Properties of Rare Earth Ions[J]. Proc. Phys. Soc., 1952, A65: 209-211.

[17] Kuang XY. Analysis of the Electron Paramagnetic Resonance Zero-field Splitting for in Sapphire[J]. Phys. Rev. B, 1987, 36: 712-714.

[18] Kuang XY. Zero-field Splitting Theory of Transition Metal Ions in Half-full State in Crystal[D], 1994 France: University of Paris Xi. 20-21.

[19] Vleck JHV. Theory of the Variations in Paramagnetic Anisotropy Among Different Salts of the Iron Group[J]. Phys. Rev., 1932, 41: 208-212.

[20] Zhao MG, Bai GR, Jin HC. d-orbital Theory for Mn²⁺-complex Ions in Crystals[J]. J. Phys. C: Solid State Phys., 1982, 15: 5 959-5 963.

[21] Lohr LL Jr. Optical Spectra of Divalent Manganese Salts. I. Energy Levels for Cubic and Lower-Symmetry Complexes[J]. J. Chem. Phys., 1966, 45: 3 611-3 616.

[22] Zheng WC. Local Trigonal Distortions of Some Paramagnetic Impurity Centers in ZnSiF₆ Center Dot 6H₂O Crystal[J]. Radiat. Eff. Defect Solids, 1997, 140: 329-332.

[23] Curie D, Barthon C, Canny B. Covalent Bonding of Mn²⁺ Ions in Octahedral and Tetrahedral Coordination[J]. J. Chem. Phys., 1974, 61: 3 048-3 052.

[24] Kuang X Y, Zhang W, Morgenstren-Badarau I. Analysis of Temperature-dependent Electron-paramagnetic-resonance Spectra for S-state Ions in MgO[J]. Phys. Rev. B, 1992, 45: 8 104-8 108.

[25] Ray S, Zalkin A, Templeton DH. Crystal Structure of the Fluosilicate Hexahydrates of Cobalt, Nickel and Zinc[J]. Acta Cryst. B, 1973, 29: 27412743.

[26] Mikenda W, Pertlik F, Steinboek S. Crystal Structures and Vibrational Spectra of MSnF₆-6H₂O(M= Fe, Co, Ni)[J]. Monatshefte für Chemie, 1995, 126: 61-66.