New X-ray powder diffraction data for thallium pentaborates TI[B5O6(OH)4].2H2O and TIB5O8

Two new arsenates with general formula A^II(ZnAsO4) (A=Sr, Ba) were synthetized by solid state reaction. Furthermore, a high pressure form of Ba(ZnPO4)2 was obtained under hydrothermal conditions. Indexing of their X-ray diffractograms was carried out with a monoclinic unit-cell and space group P2(1) /c. These compounds are isostructural with Sr(ZnPO4)2 and the paracelsian form of Ba(AlSiO4)2.