Strong anisotropic thermal expansion in cristobalite-type BPO4

Crystal structure and thermal expansion studies of α-VO(PO3)2

“…In the studied temperature range, the typical P O bond lengths remain within 1.47-1.60Å. This is the normal behavior of the PO 4 as observed in the phosphate of various materials [20][21][22][23][24][25][26]. However, the typical V O bonds, in particular the V O1 shows an increasing trend with the increase in temperature.…”

“…3. All the oxygen atoms thus, have coordination number similar to the framework arrangement of various phosphates, tungstates, molybdates or silicates [1][2][3][4][5][6][7][23][24][25][26][27]. The typical inter-polyhedral angles in the VO(PO 3 ) 2 structures are: V O1 P = 160.2(4), Table 3a Thermal expansion coefficients of ␣-VO(PO 3 ) 2 as observed from high-temperature diffraction data Temperature interval α a × 10 6 ( • C −1 ) α b × 10 6 ( • C −1 ) α c × 10 6 ( • C −1 ) α ␤ × 10 6 ( • C −1 ) α v × 10 6 ( • C −1 ) …”

“…At higher temperature, low thermal expansion behavior of cristobalite type phosphates is also reported [23]. The crystal structures of these phosphates undergo a continuous change in structure leading to different structures under pressure or temperature [24][25][26][27]. Thus, these broad interests make the vanadium phosphorus oxide system important classes of material to further investigate.…”

O K-edge XANES studies of alkali germanophosphate glasses

“…The structure of BPO 4 is also analogous to cristobalite and contains alternating corner-sharing tetrahedra of PO 4 and BO 4 [31]. It also exhibits seven peaks at 531.5 eV (peak a), 532.2 eV (peak a'), 537.2 eV (peak d), 538.5 eV (peak e), 540 eV (peak f), 542.3 eV (peak g) and 544.3 eV (peak h) (Fig.…”

Temperature dependence of Young׳s modulus of silica refractories

“…the structure of low-temperature cristobalite), e.g. phosphates [32], it has to be emphasized that high-temperature cristobalite is cubic and therefore its thermal expansion is isotropic. On the other hand, the volumetric changes connected with the tridymite transitions are very small (see below).…”