Caractérisation et prévision structurale d'une nouvelle variété de Li3PO4

Correlation between Raman wavenumbers and P?O bond lengths in crystalline inorganic phosphates

“…A model structure obtained by tripling one of the parameters in the unit cell of the lowtemperature form (ˇ) 85 gives P-O bond lengths far outside the normal expected range for orthophosphates. Valence bond calculation showed that the structure was not reliable; 10 bond valence sums at the P atoms were in good agreement with expected formal oxidation state of P 5C for the first two forms (ˇand ), but not for the third form (˛).…”

Raman spectroscopic study of phase transitions in Li3PO4

“…1) were calculated using the hkl reflection data from previous studies. 1,3,7 Figure 1 shows that thę phase predicted in Ref. 7 is not similar to the other 2θ / degrees Figure 1.…”

“…1,3,7 Figure 1 shows that thę phase predicted in Ref. 7 is not similar to the other 2θ / degrees Figure 1. Comparison of the calculated powder diffraction patterns of Li 3 PO 4 forms: the low-temperature form,ˇ, the medium-temperature form, , and the high-temperature form, .…”

“…3 This polymorph is kinetically stable to room temperature (the transition is irreversible), even though the thermodynamically stable polymorph below 400°C is thef orm. Reculeau et al 7 suggested the structure of the˛form by tripling the b parameter of theˇform [a˛D 6.275 4 ³ aˇ, b˛D 15.995 7 ³ 3bˇ, c˛D 4.766 3 ³ cˇÅ, space group Pmn2 1 ). This latter polymorph (˛) is stable for a short range of temperatures below the melting-point.…”

“…two forms, although this is not unusual since isomorphic forms of an inorganic solid may crystallize in different crystal structures, giving rise to very different powder xray patterns. InTable 1, the calculated pattern obtained here is compared with that observed for˛-Li 3 PO 4 in Ref 7,. and this reveals that the calculated and observed patterns are not compatible.…”