Abstract
The crystal structures of two solid solution phases found to occur in the Zn3(PO4)2–Cd3(PO4)2 system, one with composition near to CdZn2(PO4)2 and the other near to Cd2Zn(PO4)2, have been determined. Although these compounds are closely related structurally, there is a miscibility gap between the two phases and an apparent phase transition in only one of these. The compounds, named Bss and Css respectively, have lattice parameters a = 9.032(4) Å, b = 11.417(5) Å, c = 5.952(6) Å, β = 98.8(2), and Z = 4 for the former compound, and a = 9.056(8) Å, b = 11.86(1) Å, c = 6.190(9) Å, β = 100.1(2) and Z = 4 for the latter. Both compounds are monoclinic and crystallize with the space group P21/c with closely related, but not identical, structures to that of the mineral graftonite. The anions are slightly irregular PO43− tetrahedra with average P—O bond distances of 1.538 Å and 1.545 Å for those in Bss and 1.55 Å and 1.56 Å for those in Css. The cations are found to be coordinated to 7, 4, and 5 oxygen atoms for the 3 independent sites per unit cell. In Css the second cation site has a fifth oxygen atom at 2.57 Å in comparison with a length of over 2.9 Å for this same interatomic distance in Bss. The cations appear to be ordered with Cd++ preferentially in site 1 in Bss and Zn++ preferentially in site 2 in Css.
Publisher
Canadian Science Publishing
Subject
Organic Chemistry,General Chemistry,Catalysis
Cited by
21 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献
1. Seven-Coordination Chemistry;Progress in Inorganic Chemistry;2007-03-09
2. A kinetic model for three-site intracrystalline ordering-disordering in minerals;Geochimica et Cosmochimica Acta;1996-06
3. Mercury(II) arsenate, a graphtonite-type structure;Acta Crystallographica Section C Crystal Structure Communications;1993-04-15
4. Etude cristallochimique du phosphate tricadmique obtenu sous haute pression;Bulletin de Minéralogie;1985
5. Article;Le Journal de Physique Colloques;1984-11