scholarly journals Hydrothermal synthesis of monostructured LaPO4: morphology and structure

2018 ◽  
pp. 12-19
Author(s):  
Kairat Kenges ◽  
Mailybi Aldabergenov ◽  
Olga Proskurina ◽  
Victor Gusarov
Keyword(s):  
Crystal Structure ◽  
Hydrothermal Synthesis ◽  
Alkaline Earth ◽  
High Radiation ◽  
High Chemical ◽  
Lanthanum Phosphate ◽  
Morphology And Structure ◽  
Effects Of Ph ◽  
High Level ◽  
High Chemical Stability

The application field of materials based on lanthanum orthophosphate (LaPO4) including nanomaterials, has been permanently extending recently. The high level of mechanical properties and the compatibility with numerous oxides make it possible to consider the possibility of using lanthanum orthophosphate as a composite material for construction purposes. This application is particularly promising when nanoparticles with quasi-1D morphology (nanorods) are used. The high isomorphic capacity of the LaPO4-based phase for alkaline-earth ions and ions of lanthanides and actinides, high chemical stability, and high radiation hardness make promising the application of this compound as a matrix for immobilization of radioactive wastes. The possibility of obtaining lanthanum phosphate (LaPO4) by the hydrothermal method is considered in the work. Effects of pH, temperature and time of processing of hydrothermal synthesis on the morphology and structure of monostructured lanthanum phosphate are studied. It has been established that, with the increase of pH, the morphology of phosphate changed, the size of the crystallites increased, while the crystal structure changed from hexagonal to monoclinic.

Thermal Energy Storage and Control

1975 ◽  
Vol 97 (3) ◽  
pp. 893-896 ◽  
Author(s):  
J. Schro¨der
Keyword(s):  
Heat Supply ◽  
Alkaline Earth ◽  
Heat Pipes ◽  
Alkaline Earth Metals ◽  
Melting Points ◽  
High Chemical ◽  
Heat Engines ◽  
High Level ◽  
And Control ◽  
High Chemical Stability

Eutectic fluoride mixtures of alkali and alkaline earth metals posses extremely high thermal storage capacities, and are therefore suitable for space heating as well as for powering heat engines. Their melting points ranging from 449 to 832° C are well adapted to any high level heat supply. The compounds are of high chemical stability and show no corrosive action with stainless steel. In order to make efficient use of the stored heat, good thermal insulation and controllable heat transfer are achieved by a multifoil insulation jacket with a controllable hydrogen filling. For powering engines energy transfer is realized by heat pipes.

Heats of Formation of Alkali Metal and Alkaline Earth Metal Oxides and Hydroxides:  Surprisingly Demanding Targets for High-Level ab Initio Procedures

2003 ◽  
Vol 107 (29) ◽  
pp. 5617-5630 ◽  
Author(s):  
Michael B. Sullivan ◽  
Mark A. Iron ◽  
Paul C. Redfern ◽  
Jan M. L. Martin ◽  
Larry A. Curtiss ◽  
...  
Keyword(s):  
Alkali Metal ◽  
Metal Oxides ◽  
Ab Initio ◽  
Alkaline Earth ◽  
Earth Metal ◽  
Heats Of Formation ◽  
Alkaline Earth Metal ◽  
Alkaline Earth Metal Oxides ◽  
High Level

The first proof of protonated anion tetrahedra in the tsumcorite-type compounds

2004 ◽  
Vol 68 (5) ◽  
pp. 757-767 ◽  
Author(s):  
T. Mihajlović ◽  
H. Effenberger
Keyword(s):  
Crystal Structure ◽  
Hydrothermal Synthesis ◽  
Single Crystal ◽  
Diffraction Data ◽  
Title Compound ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Hydrogen Atoms ◽  
Synthetic Compounds ◽  
X Ray

AbstractHydrothermal synthesis produced the new compound SrCo2(AsO4)(AsO3OH)(OH)(H2O). The compound belongs to the tsumcorite group (natural and synthetic compounds with the general formula M(1)M(2)2(XO4)2(H2O,OH)2; M(1)1+,2+,3+ = Na, K, Rb, Ag, NH4, Ca, Pb, Bi, Tl; M(2)2+,3+ = Al, Mn3+, Fe3+, Co, Ni, Cu, Zn; and X5+,6+ = P, As, V, S, Se, Mo). It represents (1) the first Sr member, (2) the until now unknown [7]-coordination for the M(1) position, (3) the first proof of (partially) protonated arsenate groups in this group of compounds, and (4) a new structure variant.The crystal structure of the title compound was determined using single-crystal X-ray diffraction data. The compound is monoclinic, space group P21/a, with a = 9.139(2), b = 12.829(3), c = 7.522(2) Å, β = 114.33(3)°, V = 803.6(3) Å3, Z = 4 [wR2 = 0.065 for 3530 unique reflections]. The hydrogen atoms were located experimentally.

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