Wavenumber (cm−1) | IR Assignments | Ref |
750 - 780 | Symmetric stretching mode of P-O-P linkage in the Q2 units | [43] [44] |
840 - 880 | Stretch vibration of P-O-B linkage in BO4 units | [30] [45] |
Symmetric mode of P-O-P in linear Q2 units (metaphosphate) | [43] [46] | |
930 - 950 | Stretch vibration of B-O in BO4 units (diborate group) | [47] [48] |
1020 - 1070 | Stretch vibration of B-O in BO4 units (triborate, tetraborate, pentaborate) | [30] [49] |
1237 - 1280 | Modes of boron?oxygen triangular BO3 units (Pyro and ortho borate groups) | [50] [51] |
1230 - 1290 | Asymmetric stretching mode of the two non-bridging oxygen atoms bonded to phosphorus atoms in the Q2 tetrahedral sites | [52] [53] |
P=O asymmetric stretching vibration | [54] [55] |