The polymorphic forms II and III of paracetamol were obtained by melting the marketed form I. Under the melting and cooling conditions used, it was possible to obtain forms I, II and III. The recrystallization conditions and the physical properties of forms II and III were investigated by means of various techniques: thermomicroscopy, DSC analysis, infrared microspectrometry and X-ray powder diffraction at room temperature and as a function of temperature. Form III was found to be very unstable. However, its formation seems to be an important intermediate step in the preparation of form II.

No abstract

No abstract

Inorganic chemistry Z 0100 Structures and Oxide Mobility in Bi-Ln-O Materials: Heritage of Bi2O3 -[130 refs.]. -(DRACHE*, M.; ROUSSEL, P.; WIGNACOURT, J.-P.; Chem. Rev. (Washington, D. C.) 107 (2007) 1, 80-96; Unite Catal. Chim. Solide, CNRS, Ec. Natl. Super. Chim. Lille, F-59652 Villeneuve d'Ascq, Fr.; Eng.) -Schramke 16-225

No abstract

No abstract

No abstract

The binary system PbO-BiV04 exhibits two new phases, Pb,BiV08 and Pb2BiV06. They both melt congruently at 780 "C. They haye been identifi!d by single-cry?tal and powder X-ray diffraction. Pb4BiV08 crystallizes with a triclinic cell, a = 6.221 (2) A, b = 7.603(5) A, c = 10.457(4) A, a = 100.40(3)", p = 102.1 8(2)", y = 90.03(3)" and Z = 2. Pb2BiV06 exhibits four phase transitions at 300, 4105, 475 and 600 "C. The a phase, room-temperature form, is monoclinic with a = 7.642( 6) A, b = 5.81 265, A, c = 28.85j2) A, p = 100.3(1)" and Z 8. The p and . y phases are ythorhombic with a = 8.381 (6) A, b = 16.65(1) A, c = 4.859(6) A, Z= 4 and a = 14.304(7) A, b = 10.1 4(1) A, c = 9.923(4) A, Z = 8, respectively. The 6 phase is tetragonal with a = 12.1 1 O(2) A, c =9.472(8) A and Z=8.Bismuth-based mixed oxides exhibit a wide variety of structures and display physical properties such as ionic conductivity or non-linear properties (ferroelectricity etc). Our previous investigations of binary oxide systems including Bi,03-P20, ,' Bi20,-Pb0,2 Pb0-V205,3 Bi,03-V2054 and B~,O,-AS,O~~ have highlighted a potential interest in extending this work to ternary systems such as Bi,03-PbO-M205 ( M = V, P, As). The investigation with M = V is under progress. This paper describes partial results concerning the PbO-BiV04 binary system which exhibits the known PbBiVO, phase6 and two new phases, Pb2BiV06 and Pb4BiVO8.