Chemical preparation, crystallographic characterization, vibrational study and thermal behavior of a new cyclotriphosphate CaNH₄P₃O₉ · H₂O

Abstract

Chemical preparation, crystallographic characterization, IR studies and thermal behavior are presented for the new cyclotriphosphate CaNH₄P₃O₉ · H₂O and its anhydrous form CaNH₄P₃O₉. CaNH₄P₃O₉ · H₂O was prepared by the method of ion exchange resin. CaNH₄P₃O₉ · H₂O crystallizes hexagonal, space group is P6₃ or P6₃/m or P6₃22 with the following unit-cell dimensions: a = b = 14.75(2) Å, c = 9.934(3) Å and Z = 8. The total dehydration of CaNH₄P₃O₉ · H₂O, between 70 °C and 180 °C, leads to its anhydrous form CaNH₄P₃O₉. CaNH₄P₃O₉ crystallizes in the monoclinic space group P2₁/n, Z = 4, with the following unit-cell dimensions: a = 7.446 Å, b = 12.46 Å, c = 10.050 Å, β = 90.11° and Z = 4. CaNH₄P₃O₉ · H₂O is stable until its melting point at 1050 °C. The thermal behavior of CaNH₄P₃O₉ · H₂O was investigated and interpreted by comparison with IR absorption spectrometry and X-ray diffraction experiments.

Graphical Abstract

Keywords:

• Cyclotriphosphate
• XRD
• IR
• TGA
• DTA