hide
Free keywords:
AlPO4-5;
AlPO4-36;
Large crystals;
Synthesis
Abstract:
Large, perfect hexagonally shaped AlPO4-5 crystals with maximum length up to 1.4 mm have been crystallized in hydrothermal syntheses carried out at 453 K with a crystallization period of 20 h. The improved length growth is attributed to the replacement of triethylamine (TEA) with tripropylamine (TPA) and to higher dilution of the gel. Better crystal quality is achieved by using ultra-purified water. Insolubility of the template in the absence of alcohol induces deep pits in the surface of the crystals, although the length is retained and reaches up to 1.0 mm. During these experiments a new by-product for AlPO4-5 syntheses has been identified and structurally classified as AlPO4-36. This is in contrast to previously used synthesis systems with triethylamine, in which only dense aluminumphosphate phases were identified as by-products.
