Mixed insoluble acidic salts of tetravalent metals VI. Crystalline mixed zirconium-titanium arsenate and hafnium-titanium arsenate

Mixed crystalline zirconium-titanium arsenates ZrxTi(1−x) (HAsO4)2·H2O and harnium-titanium arsenates HfxTi(1−x) (HAsO4)2 H2O (where x=0–1) of various compositions with different Zr/Ti or Hf/Ti ratios have been prepared. The compounds have been characterized by X-ray, thermal analysis, chemical analysis, and pH-titrations. For powder X-rays, the compounds appear to be homogeneous crystalline materials with structures similar to α-ZrP, α-TiP or α-ZrTiP. The thermograms show a loss of approximately two moles of H2O, followed by a small loss of O2 with probable formation of ZrO2, As2O3, HfO2, As2O3, ZrO2, As2O5, HfO2, As2O5 from which As2O3 and As2O5 are practically sublimed in two steps. The exchange capacities at r.t. are generally similar to α-ZrP and α-TiP but are found to be much lower in value.