Chemical preparation, crystallographic characterization, thermal behavior and IR studies of a new cyclotriphosphate SrTlP 3O 9·3H 2O

Abstract

Chemical preparation, crystallographic characterization, thermal behavior and IR studies are given for two new cyclotriphosphates SrTlP 3O 9·3H 2O and SrTlP 3O 9. SrTlP 3O 9·3H 2O is orthorhombic, space group Pnma, with the following unit-cell dimensions: a=9.147(7) Å, b=8.180(7) Å, c=15.458(2) Å and Z=4. The total dehydration of SrTlP 3O 9·3H 2O leads between 300 and 650°C to its anhydrous form SrTlP 3O 9. SrTlP 3O 9 is monoclinic, space group P2 1/ m or P2 1, with the following unit-cell dimensions: a=14.544(2) Å, b=8.639(1) Å, c=7.727(1) Å, β=102.05(1)° and Z=4. The thermal behavior has been investigated and interpreted in agreement with IR absorption spectrometry and X-ray diffraction experiments. We calculated the 30 normal frequencies of the P 3O 9 ring with Cs symmetry and proposed the interpretation of the vibrational spectrum of SrTlP 3O 9·3H 2O. The vibrations were assigned and precised to each frequency for different atoms of the ring on the basis of the results of the theoretical isotopic substitutions and in the light of the crystalline structure of the isotypic compounds, SrM IP 3O 9·3H 2O (M I=Rb +, K + and NH 4 +), of SrTlP 3O 9·3H 2O.