Isomorphous Substitution of Calcium by Praseodymium (III) in Synthetic Calcium Vanadate Apatite
Location
CSU Ballroom
Start Date
9-4-2012 10:00 AM
End Date
9-4-2012 11:30 AM
Student's Major
Chemistry and Geology
Student's College
Science, Engineering and Technology
Mentor's Name
Lyudmyla Ardanova
Mentor's Department
Chemistry and Geology
Mentor's College
Science, Engineering and Technology
Description
Compounds with the apatite structure have the general composition M5(EO4)3X, where M are univalent to trivalent cations (Ca+2, Sr+2, La+3, Pr3+, Na+, K+ etc); E are tetravalent to hexavalent elements (P+5, V+5, As+5, Si+4, Ge+4, Cr+6 etc); and X represents anions OH-, F-, Cl-, O-2. An important property of apatite compounds is their ability to undergo isomorphic substitutions: different elements can substitute for the major constituents in their crystal structures without change the crystal structure overall. Modified compounds (solid solutions) resulting from these substitutions have changed and often improved physical properties. Therefore, isomorphic substitutions are widely studied and used for synthesis of different functional materials (catalysts, sorbents, and luminophores). Solid solutions based on calcium hydroxyapatite Ca₅(PO₄)₃OH play very important role in many physiological processes occurring in a human body and considered to be the most biologically compatible. However, little has been studied on isomorphic substitutions in hydroxovanadate Ca₅(VO₄)₃OH with apatite structure substituted by Rare-Earth elements. These compounds can be used as luminescent, laser material, and catalysts. In this work we studied isomorphic substitututions of praseodymium (Pr³+) for calcium (Ca2+) in calcium hyrdoxovanadate under the scheme: Ca2+ + OH- → Pr³+ + O²-. Using X-ray diffractional analysis the solubility limits in the system Ca(5-x)Prx(VO4)3(OH)(1-x)Ox were established in the range 0 ≤x≤0.60 . Each sample of the solid solution was prepared from nitric-tartaric aqueous solution and calcined for 18 hours at the temperature of 750°C. The apatite solid solutions coexist with unknown X phase in heterogeneous regions of the system.
Isomorphous Substitution of Calcium by Praseodymium (III) in Synthetic Calcium Vanadate Apatite
CSU Ballroom
Compounds with the apatite structure have the general composition M5(EO4)3X, where M are univalent to trivalent cations (Ca+2, Sr+2, La+3, Pr3+, Na+, K+ etc); E are tetravalent to hexavalent elements (P+5, V+5, As+5, Si+4, Ge+4, Cr+6 etc); and X represents anions OH-, F-, Cl-, O-2. An important property of apatite compounds is their ability to undergo isomorphic substitutions: different elements can substitute for the major constituents in their crystal structures without change the crystal structure overall. Modified compounds (solid solutions) resulting from these substitutions have changed and often improved physical properties. Therefore, isomorphic substitutions are widely studied and used for synthesis of different functional materials (catalysts, sorbents, and luminophores). Solid solutions based on calcium hydroxyapatite Ca₅(PO₄)₃OH play very important role in many physiological processes occurring in a human body and considered to be the most biologically compatible. However, little has been studied on isomorphic substitutions in hydroxovanadate Ca₅(VO₄)₃OH with apatite structure substituted by Rare-Earth elements. These compounds can be used as luminescent, laser material, and catalysts. In this work we studied isomorphic substitututions of praseodymium (Pr³+) for calcium (Ca2+) in calcium hyrdoxovanadate under the scheme: Ca2+ + OH- → Pr³+ + O²-. Using X-ray diffractional analysis the solubility limits in the system Ca(5-x)Prx(VO4)3(OH)(1-x)Ox were established in the range 0 ≤x≤0.60 . Each sample of the solid solution was prepared from nitric-tartaric aqueous solution and calcined for 18 hours at the temperature of 750°C. The apatite solid solutions coexist with unknown X phase in heterogeneous regions of the system.
Recommended Citation
Powers, John. "Isomorphous Substitution of Calcium by Praseodymium (III) in Synthetic Calcium Vanadate Apatite." Undergraduate Research Symposium, Mankato, MN, April 9, 2012.
https://cornerstone.lib.mnsu.edu/urs/2012/poster-session-A/27
