| Autor: |
M. Rojo, José, L. Mesa, José, Lezama, Luis, Rojo, Teófilo |
| Zdroj: |
Journal of Materials Chemistry; November 1997, Vol. 7 Issue: 11 p2243-2248, 6p |
| Abstrakt: |
Three metaphosphates with formula M(PO3)3 (M=Cr and Mo) and Cr2(P6O18) have been synthesized and characterized. IR data allow establishment of a good correlation between the vibrational frequencies and the chain or ring structures of the M(PO3)3 (M=Cr, Mo) metaphosphates and the Cr2(P6O18) hexametaphosphate, respectively. The reflectance diffuse spectra show bands belonging to the CrIII and MoIII cations in octahedral symmetry. The values of 10Dq and Racah parameters B and C have been calculated. The percentage of reduction calculated for the B parameter (≈70%) is indicative of a significant degree of covalence in the M–O (M=Cr, Mo) bonds. The EPR spectra of the metaphosphate compounds have been explained on the basis of the existence of more than one different environment for the metallic cations. In doped aluminium metaphosphates with CrIII and MoIII ions the EPR data indicate the presence of one centre with |D|>hν and two centres with |D|
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| Databáze: |
Supplemental Index |
| Externí odkaz: |
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