Studies of phosphate melts and glasses. Part III. Infra-red spectra of some binary phosphate and phosphate–fluoride glasses

JSGT 1959 V43 T337-T351

 Using the K.Br-disc technique, the infra-red absorption spectra of the binary phosphates of sodium, potassium, calcium, and lithium, with compositions from the metaphosphate to the pyrophosphate, have been determined over the range 211 to 15 µ. Similarly the spectra of some sodium phosphate glasses to which NaF had been added were studied using the same technique and over the same spectral range. Similarities in the spectra of the metaphosphates of sodium, calcium, and lithium suggest a similar structure for each, but for the potassium metaphosphate, the very different spectrum obtained indicates a radical difference in the symmetry of the polyphosphate chain in the solid state. The addition to the metaphosphates of the appropriate metal oxide as network modifiers and also of NaF to the sodium metaphosphate, cause radical changes in the spectra producing new peaks and varying the percentage absorption due to various vibrating bonds. The P–O–P stretching frequency in the region of 880 cm⁻¹ increases in frequency with reduction in the phosphate chain length.

D. J. Williams, B. T. Bradbury & W. R. Maddocks