Mineralogical Character of Some Iron and Aluminum Phosphates Containing Potassium and Ammonium

Low Temperature Syntheses of Highly-ordered Framework Materials: The Aluminium Phosphate Ammonium Taranakite

“…Natural occurrences have been reported from several locations including the Omino-Iwaya limestone cave, Japan [16] and Mimegarra, West Australia [17]. Structural analogues obtained by Hasemann and co-workers [18,19] by the treatment of ªmicaº with phosphate solutions have been further investigated by Smith and Brown [20] who suggested a general formula of M 2 H 4 K 3 (Al,Fe) 5 (PO 4 ) 8´× H 2 O. Because of these observations it has been suggested that taranakite might be formed from the interaction of soils with acidic phosphates resulting from the dissolution of phosphate fertilizers in a natural environment [18].…”

“…Though the structure of taranakite is still unknown there is strong evidence that it is not a framework aluminium phosphate but a layered material [19,20]. Thus, McConnell discussed the similarities between taranakite and layered aluminosilicates and proposed that taranakite should be a phylloposphate with a hexagonal symmetry analogous to illite [27].…”

Phosphate minerals formed by reaction of bird guano with basalt at Cooks Head Rock and Green Island, Otago, New Zealand

“…The most likely explanation for the occurrence of these potassic phosphate minerals lies in their lower solubility (than many phosphate minerals) which allows preservation in a damp climate. Haseman et al (1950Haseman et al ( , 1951 suggested that K-Al-Fe phosphates such as taranakite and leucophosphite may form in damp soils; see also discussion in Reed (1965). Although taranakite and leucophosphite have not yet been documented from soils, the east Otago occurrences provide further evidence that phosphate could be fixed in soils in these minerals.…”

Francoanellit K3Al5HPO4)6(PO4)2 · 12H2O: Struktur und Synthese durch topochemische Entwässerung von Taranakit / Francoanellite K3Al5HPO4)6(PO4)2 · 12H2O: Structure and Synthesis by Topochemical Dehydration of Taranakite

“…Das Mineral Francoanellit wurde erstmals im Jahre 1976 von Balenzano, Dell'Anna und Di Pierro [1] als Bestandteil von mit Fledermausguano ver unreinigter "terra rossa" einer apulischen Höhle be schrieben und als natürliches Analogon einer Ver bindung erkannt, die man schon vorher durch vor sichtiges Dehydratisieren von synthetischem Ta ranakit K^HöAh^PC^g -18H2O erhalten hatte [2,3]. Chemische Analysen der natürlichen und synthe tischen Verbindungen sowie thermogravimetrische Untersuchungen legten für Francoanellit die Zu sammensetzung K3H6Al5(P0 4)g l 3 H2 0 [1 ,4 ] habitus und Röntgenpulverdiffraktogramm führten zu der Annahme, daß Francoanellit und Taranakit strukturell eng verwandt sind.…”