Temperature-dependent Raman spectroscopic study on orthophosphates Ba3(PO4)2 and Sr3(PO4)2

Abstract

Temperature-dependent Raman spectroscopic study on orthophosphates Ba3(PO4)2 and Sr3(PO4)2 were carried out up to 900 ℃. The change of Raman lines and crystal structure has been investigated at high-temperatures. It is found that all the Raman lines exhibit a decrease in frequency shifts and the width of the Raman lines increases with the increase in temperature. The P-O bond lengths in the crystal increase in high- temperature, but the O-P-O bond angles have less change. No phase changes have been observed under 900 ℃.

High-temperature Raman spectroscopic study of vanadoborate Na3VO2B6O11

“…These phenomena also appear in the hightemperature Raman spectra of Bi 12 SiO 20 , KTa1 1−x Nb x O 3 , Ba 3 (PO 4 ) 2 , BiB 3 O 6 , and Bi 2 ZnOB 2 O 6 crystals. [28][29][30][31][32] The weak band at 950 cm −1 becomes overlapped and merges together with the band at 930 cm −1 after the temperature increases to 150 • C. However, the spectra of the NVBO crystal do not show any splitting or new bands, which indicates that no phase transition occurs under 525 • C in the present study. However, the Raman spectrum of NVBO crystal becomes dramatic when the temperature increases to the melting point (about 610 • C).…”

Exposing the (002) active facet by reducing surface energy for a high-performance Na3V2(PO4)2F3 cathode

“…The two bands at 520 and 575 cm −1 were ascribed to ν 4 vibration, while the bands at 935 and 900 cm −1 could be attributed to the A 1g symmetric P–O stretching vibration bands of ν 1 , and the higher band at 1035 cm −1 was attributed to the antisymmetric stretching band of the PO 4 anion ( ν 3 ). 46,47 Thermogravimetric analysis (TGA) was used to characterize the mass changes of the two samples from 30 °C to 600 °C in a nitrogen atmosphere at a heating rate of 5 °C min −1 . As shown in Fig.…”

“…The performances of compounds exposed to different facets usually vary, and similar situations also exist in the cathode. 31,32,36,37,39–51 Fig. 2j and k show the SRXRD patterns of the as-prepared NVPFs at 15°–31°.…”

Temperature-dependent Raman spectroscopic study of bismuth borate Bi2ZnOB2O6

“…These phenomena also appear in the high-temperature Raman spectra of Bi 12 SiO 20 , KTa 1−x NbxO 3 , Ba 3 (PO 4 ) 2 , and BiB 3 O 6 crystals. [34][35][36][37] With increasing temperature, all of the peaks decrease in frequency, which is ascribed to the increases in the inter-atomic distances in the BZB crystal when the crystal is heated. [38] In addition, the Raman peaks become wider during the heating process, the bending vibration of the B-O bands at 743 cm −1 becomes a shoulder at 700 cm −1 after the temperature increases to 400 • C, as a consequence of larger distributions of the bonding angles and distances at higher temperature.…”