Investigation of CuI-Containing Molybdophosphate Glasses by Infrared Reflectance Spectroscopy

Abstract

Superionic glasses xCuI–(l – x)[Cu2MoO4–CuPO3] were prepared and studied by infrared reflectance spectroscopy to investigate the structure of the oxyanion matrix and the type of sites occupied by copper ions. The study was complemented by the consideration of glasses 0.67CuI–0.33[Cu2MoO4–Cu3PO4] and xCuI–(l – x)[Cu2O-nP2O5] with n = 0.33, 0.50, 1.0. The oxyanion structure of glasses xCuI–(l – x)[Cu2MoO4–CuPO3] was found to involve discrete PO4 3‑, P2O7 4‑ and MoO4 2‑ units, where P and Mo are 4-fold coordinated to oxygen, and molybdate octahedral species which have the MoO3 stoichiometry and are linked by Mo–O–Mo bridging bonds. Despite the nominal metaphosphate composition (CuPO3) of these glasses the spectra gave no signature for metaphosphate structures based on the PO3 – unit. Also, increasing amounts of CuI were found to favor the creation of PO4 3‑ and MoO3 species at the expense of P2O7 4‑ and MoO4 2‑. These findings were explained by the acidity order P2O5 > MoO3 and the need to accommodate the bulky CuI in the glassy matrix, a process facilitated by condensed MoO3 octahedral species. Cu ions were found to be present as monovalent cations and to occupy oxide and iodide sites. The latter sites organize into CuI-like pseudophases at high CuI contents, in agreement with the conduction pathway model for superionic glasses.

Partitioning and structural role of Mn and Fe ions in ionic sulfophosphate glasses

“…of P-O-P bridges, ν as (P-O-P), connecting pyrophosphate (Q 1 ) units, with the infrared active ν as (PO 3 2− ) mode of Q 1 units being observed at ∼1070 cm −1 . 36,39,43 The decrease of the relative intensity of both the 947 and 1070 cm −1 IR bands with increasing MnO doping is fully consistent with the corresponding Raman spectra which showed a decrease in the relative population of Q 1 units upon doping (Figs. 7 and 10).…”

“…13) is consistent with this expectation, as this feature can be attributed to ν 3 (PO 4 3− ). 43 Also, the lowerfrequency feature developing at ∼565 cm −1 can be associated with the ν 4 (PO 4 3− ) mode of Q 0 species. 43 However, quantification of the effect of doping on the basis of IR spectra alone is difficult because of the strong overlapping of the different phosphate and sulfate vibrational bands.…”

“…43 Also, the lowerfrequency feature developing at ∼565 cm −1 can be associated with the ν 4 (PO 4 3− ) mode of Q 0 species. 43 However, quantification of the effect of doping on the basis of IR spectra alone is difficult because of the strong overlapping of the different phosphate and sulfate vibrational bands. Nevertheless, several IR features manifest in a qualitative manner the effect of doping on the glass structure.…”

Phosphate structure and lithium environments in lithium phosphorus oxynitride amorphous thin films

“…3 ), units can be seen. The infrared bands between 700 and 850 cm 1 are associated with symmetric stretching modes of P-O-P linkages, while the broad band observed in the far-IR region, 200-550 cm 1 , is assigned to vibrations of Li cations against their sites in the oxide glass matrix [9,10,[35][36][37]. On the other hand, the lithium phosphate film (i.e., sample N0-10 deposited under Ar) presents large spectral variations after air exposure (Fig.…”

“…Kamitsos et al [31] have observed for alkali oxidecontaining glasses the occurrence of more than one cation motion band in the far-IR originating from the existence of more than one type of cation-hosting anionic sites differing mainly in the coordination of alkali cation. Following this methodology, the far-IR envelope has been analyzed using spectral decomposition based on similar treatments for the far-IR spectra reported for borate, phosphate, and germanate glasses [31,35,36,44,45]. Figure 4 presents the decomposition of the far-IR region for samples N0-10, N5-5, and N10-0.…”