Solventothermal Synthesis and Structure of Lamellar Alkali Metal Selenidostannates(IV) A4Sn4Se10·xH2O with 20- (A=Cs; x=3.2) and 36-Membered Pores (A=K, Rb; x=4.5, 1.5)

✍ Scribed by Anja Loose; William S Sheldrick

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 430 KB
• Volume: 147
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1999.8205

✦ Synopsis

Treatment of A 2 CO 3 (A ‫؍‬ K, Rb) with Sn and Se in an H 2 O/CH 3 OH mixture at 1303C a4ords reaction solutions from which respectively K 4 Sn 4 Se 10 ' 4.5H 2 O (1) and Rb 4 Sn 4 Se 10 ' 1.5H 2 O (2) can be isolated on cooling. 1 crystallizes in the rhombohedral space group R3 with a ‫؍‬ b ‫؍‬ 15.320(3) A s , c ‫؍‬ 21.019(7) A s , Z ‫؍‬ 6, V ‫؍‬ 4272(2) A s 3 , 2 in the same space group with a ‫؍‬ b ‫؍‬ 15.539(2) A s , c ‫؍‬ 21.373(4) A s , Z ‫؍‬ 6, V ‫؍‬ 4469.4(13) A s 3 . These isotypic phases contain lamellar 2 [Sn 4 Se 4؊ 10 ] polyanions in which SnSe 4؊ 4 and [Sn 2 Se 6 ] 4؊ molecular building units are corner-bridged into a 6 3 net with 36-membered cavities of 1.3؋1.4 nm cross-section. Cs 4 Sn 4 Se 10 ' 3.2H 2 O (3) can be prepared under similar mild solventothermal conditions. It crystallizes in the triclinic space group P1 with a ‫؍‬ 7.235(1) A s , b ‫؍‬ 9.468(2) A s , c ‫؍‬ 11.235(2) A s , ‫؍‬ 68.77(3)3, ‫؍‬ 83.25(3)3, ‫؍‬ 84.53(3)3, Z ‫؍‬ 1, V ‫؍‬ 711.2(2) A s 3

. In contrast to the 2-dimensional anions of the same formula type in 1 and 2, the 2 [Sn 4 Se 4؊ 10 ] polyanions of 3 consist of 1 [SnSe 2؊ 3 ] ribbons that are corner-bridged through ditetrahedral [Sn 2 Se 6 ] 4؊ units into sheets with smaller 20-membered pores. The role of starting pH, cation size and temperature on the construction of lamellar selenidostannates(IV) are discussed.