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 ${\text{B}}_{\text{4}}{\text{O}}_7^{2-}$ 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]