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Group 10 and Group 12 One-Dimensional Selenodiphosphates:A2MP2Se6(A=K, Rb, Cs;M=Pd, Zn, Cd, Hg)

✍ Scribed by Konstantinos Chondroudis; Mercouri G. Kanatzidis


Book ID
102605368
Publisher
Elsevier Science
Year
1998
Tongue
English
Weight
406 KB
Volume
138
Category
Article
ISSN
0022-4596

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✦ Synopsis


The reaction of M (M‫؍‬Pd, Zn, Cd, Hg) with a molten mixture of A 2 Se/P 2 Se 5 /Se produced the quaternary compounds A 2 MP 2 Se 6 (A‫؍‬K, Rb, Cs; M‫؍‬Pd, Zn, Cd, Hg). The crystals of A 2 MP 2 Se 6 are air-and water-stable. For Cs 2 PdP 2 Se 6 (1): monoclinic C2/c (No. 15) with a‫)4(0579.21؍‬ A s , b‫)2(2823.8؍‬ A s , c‫)1(8650.31؍‬ A s , ‫,°)2(049.201؍‬ Z‫,4؍‬ and R/R w ‫.%5.7/7.6؍‬ K 2 ZnP 2 Se 6 (2), K 2 CdP 2 Se 6 (3), Rb 2 CdP 2 Se 6 (4), and Cs 2 CdP 2 Se 6 (5) are isostructural. Rb 2 CdP 2 Se 6 (4): monoclinic P2 1 /n (No. 14) with a‫)1(046.6؍‬ A s , b‫)2(927.21؍‬ A s , c‫)1(877.7؍‬ A s , ‫؍‬ 98.24(1)°, Z ‫,2؍‬ and R/R w ‫.%9.4/7.3؍‬ K 2 HgP 2 Se 6 (6) and Rb 2 HgP 2 Se 6 (7), are isostructural. K 2 HgP 2 Se 6 (6): monoclinic P2 1 /c (No. 14) with a‫)2(130.31؍‬ A s , b‫)2(803.7؍‬ A s , c‫؍‬ 14.167( 2) A s , ‫,°)1(36.011؍‬ Z‫,4؍‬ and R/R w ‫.%1.7/6.5؍‬ Compounds 1-7 contain the ethane-like [P 2 Se 6 ] 4؊ group. Compound 1 has a one-dimensional structure with Pd 2؉ in square-planar coordination. Compounds 2-5 also have one-dimensional structures related to the TiI 3 structure type. The M 2؉ ions and the P-P pairs reside in Se octahedra that share opposite faces in the chain direction. Compounds 6 and 7 have a related one-dimensional structure but with Hg 2؉ in tetrahedral coordination. The solid state single-crystal optical absorption and far-IR spectra of the compounds are reported. Compounds 2-7 melt congruently in the 540-773°C region, whereas 1 melts incongruently.