The Effect of Heat Treatment on Crystal Structure in Zircon Monitored by ESR and XRD

Influence of the surface layer of hydrated silicon on the stabilization of Co2+ cations in Zr–Si fiberglass materials according to XPS, UV-Vis DRS, and differential dissolution phase analysis

“…33,40 Zr 4+ cations in the structure of ZrSiO 4 have a coordination number of 8. 41 The theoretical calculations of NMR spectra showed that Zr 4+ cations are stabilized in the bulk of glass bers in the octahedral oxygen coordination. 30 Impregnation of glass bers with an aqueous solution of CoCl 2 containing only isolated Co 2+ Oh cations and drying at 20 C leads to stabilization of cobalt cations only in octahedral coordination.…”

“…33,40 Zr 4+ cations in the structure of ZrSiO 4 have a coordination number of 8. 41 The theoretical calculations of NMR spectra showed that Zr 4+ cations are stabilized in the bulk of glass bers in the octahedral oxygen coordination. 30 Td dimers with the size of up to 10 Å.…”

The Changed Crystal Filed of Gd3+ in Natural Zircon with Heat Treatment in Oxidizing and Reducing Atmosphere Monitor by ESR Spectroscopy

“…Since the electron configuration of Gd 3+ is [Xe]4f 7 , hence the spin quantum number, S = 7/2 and the ground state of Gd 3+ is 8 S 7/2 . The state 8 S 7/2 splits into 2S+1 = 8 states, then the seven allowed transitions according to the selection rule, ∆M S = ±1, are obtained [2][3][4][5][6]. The ESR spectra can be described by a spin Hamiltonian incorporating with Zeeman interaction, hyperfine structure and crystal field operators [7][8][9] are given by equations:…”

“…The improvement of color in gemstones depends on the atmosphere in the heating part of the furnace. Dark brown zircon, which was heated under an oxidizing atmosphere, became yellowish brown or colorless, while heated under a reducing atmosphere, it became light blue [3][4][5][6].…”

Influence of metamictization on the gemological properties of natural zircon: A Raman spectroscopic study of zircons in the gemological collection of Abraham Gottlob Werner

“…[65][66][67][68][69][70][71] The theoretical density of zircon can be calculated by its unit cell volume ranging from 255.59 to 264.16 A 3 . [17,[19][20][21]23,25,[72][73][74][75][76][77][78][79][80][81][82] The effect of nuclear radiation from the decay of uranium, thorium, and their daughter elements on the density and unit cell dimensions has been studied. During the course of the irradiation, the density of zircon drops by 16%.…”