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

Abstract

Mixed crystalline zirconium-titanium arsenates Zr_xTi(_1−x) (HAsO₄)₂·H₂O and harnium-titanium arsenates Hf_xTi(_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.