Preparation of Mixed Phosphates in Molten Alkali Metal Nitrates

Abstract

Mixed phosphates of alkali metals and main or transition group metals were obtained from the reactions of different starting salts of metals (nitrates, chlorides) and ammonium hydrogen monophosphate at 673−823 K in the alkali metal nitrate fluxes. The products obtained include submicrometer dispersions of known commercially important compounds, among which are KTiOPO4 (KTP), a number of ABPO4 phases (where A stands for alkali metal; B, bivalent transition or main group metal), as well as various substituted phases, derived from the NASICON NaZr2(PO4)3 and lamellar zirconium phosphate structure. Sometimes novel mixed phosphates were formed, such as those of sodium and nickel or cobalt, for which stoichiometric composition and/or elementary cell parameters have been established. The dependence of composition of solid products on the nature of reacting species and reaction conditions was discussed. Possible extensions of method by means of chemical modifications with admixtures of nitrite and fluoride species were considered and illustrated by several examples.

Quasi-Equilibrium, Multifoil Platelets of Copper- and Titanium-Substituted Bismuth Vanadate, Bi2V0.9(Cu0.1−xTix)O5.5−δ, by Molten Salt Synthesis

“…While evidence of edge roughness and lobes on MSS platelets can be found in previous published works [25,46,47], they generally do not appear as pronounced or as regular multifoil shapes like the BICUTIVOX material presented here. The closest example is found in Nd/V co-doped Bi 4 Ti 3 O 12 by Tang et al [47].…”

Fabrication of La2Ti2O7 Crystals Using an Alkali-Metal Molybdate Flux Growth Method and Their Nitridability To Form LaTiO2N Crystals under a High-Temperature NH3 Atmosphere

“…Therefore, the {100} face became the most prominent on the La 2 Ti 2 O 7 platelet crystals grown using the Na 2 MoO 4 and K 2 MoO 4 fluxes. Moreover, the polar {010} and {001} planes could also provide a smooth transition between the crystal and the melt, thus decreasing the free surface energy . Afanasiev also described that, if a crystalline structure contains charged planes populated with alkali-metal cations, such planes will be preferentially exposed in the crystal product.…”

Snapshots of Zinc Oxide Formation in Molten Salt: Hollow Microtubules Generated by Oriented Attachment and the Kirkendall Effect

“…Alkali metal nitrates provide a reaction medium favoring the growth of acicular crystals, exposing charged planes . As a rule, if a crystalline structure contains charged planes populated with alkali metal cations (e.g., in mixed phosphates), such planes will be preferentially exposed in the product. Similarly, anionic charged planes can be favored.…”