SYNTHESIS IN THE AMMONIUM POLYPHOSPHATE MELT AND THERMAL BEHAVIOUR OF BINARY POLYPHOSPHATES Mg(NH4)2(PO3)4 AND Ca(NH4)2(PO3)4
2005 年 18 巻 p. 93-98
詳細
2005 年 18 巻 p. 93-98
Reactions of Mg(OH)2 and Ca(OH)2 with NH4PO3 have been studied in the 300-400 °C range at the molar ratio P2O5 : MO = 4:1. Conditions of formation for two new isotypic polyphosphates M(NH4)2(PO3)4 (M = Mg, Ca) have been elaborated. The compounds are found to be isostructural with binary metaldiammonium polyphosphates M(NH4)2(PO3)4 (M = Mn, Co, Cd), monoclinic system, the space group P21/n, Z = 4. XRD studies have been performed for powder samples of Mg(NH4)2(PO3)4 [the unit cell dimensions are a = 11.233(6), b = 12.738(5), c = 7.761(4) Å; β = 101.32(5)°] and Ca(NH4)2(PO3)4 [the unit cell dimensions are a = 11.412(4), b = 13.372(8), c = 7.935(4) Å; β = 101.73(3)°]. Thermal behaviour of the polyphosphates has been investigated in the 20-1000 °C temperature range.
