title: Aluminium arsenate
text: # Aluminium arsenate
  
  Aluminium arsenate is an inorganic compound with the formula $AlAsO_4.$ It is most commonly found as an octahydrate. It is a colourless solid that is produced by the reaction between sodium arsenate and a soluble aluminium salt. Aluminium arsenate occurs naturally as the mineral mansfieldite. Anhydrous form is known as an extremely rare, fumarolic mineral alarsite A synthetic hydrate of aluminium arsenate is produced by hydrothermal method. with the formulation $Al_2O_3·3As_2O_5·10H_2O.$
  
  Modification of aluminium orthoarsenate was carried out by heating different samples to different temperatures. Both amorphous and crystalline forms were obtained. The solubility product was determined to be $10^{−18.06}$ for aluminium arsenate hydrate of formula $AlAsO_4·3.5H_2O.$ Like gallium arsenate and boron arsenate, it adopts the α-quartz-type structure. The high pressure form has a rutile-type structure in which aluminium and arsenic are six-coordinate.
  
  