Zum Mechanismus der Thermischen Dehydratisierung von Natriumdihydrogenphosphat |
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Authors: | Dr. U. Schülke R. Kayser L. Arndt |
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Affiliation: | ZI f. Anorg. Chemie d. AdW der DDR, DDR-1199 Berlin-Adlershof, Rudower Chaussee 5 |
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Abstract: | Mechanism of Thermal Dehydration of Sodium Dihydrogenphosphate The thermal dehydration of sodium dihydrogenphosphate (P1) to sodium cyclotriphosphate (CP3) and sodium polyphosphate, the so-called Maddrell's salt (MS), is controlled by nucleation and crystallization of CP3 and MS, respectively. The wellknown influence of various formation conditions on the CP3:MS product ratio is caused by amorphous and crystalline intermediate phases and their ability to form CP3 or MS nuclei. On seeding P1 with CP3 or MS the dehydration proceeds structure-controlled via dihydrogendiphosphate to pure CP3 or pure MS. The particularities of thermal dehydration of crystalline sodium dihydrogendiphosphate, and also the dehydration and reorganization of sodium phosphate glasses (Na:P = 1:1) with different mean chain lengths, under formation of CP3 or MS are described. |
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