The structures of as-synthesized AlPO4-53(A), calcined dehydrated AlPO4-53(B), and AlPO4-53(C), a new phase determined by the FOCUS method

✍ Scribed by Richard M Kirchner; Ralf W Grosse-Kunstleve; Joseph J Pluth; S.T Wilson; Robert W Broach; Joseph V Smith

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 296 KB
• Volume: 39
• Category: Article
• ISSN: 1387-1811
• DOI: 10.1016/s1387-1811(00)00205-5

✦ Synopsis

AlPO 4 -53 was synthesized hydrothermally with methylamine as a structure-directing agent. The structure of assynthesized AlPO-53(A) was solved using AlPO-EN3 as a starting model. The Rietveld re®nement converged (R P 0.140) in space group P2 1 2 1 2 1 (a 10X3212(1) #

A, b 13X6308(1) # A and c 17X4539(1) # A) for unit cell composition: Al 24 P 24 O 96 Á8.5CH 3 NH 2 Á14H 2 O. AlPO-53(A) is isotypic with as-synthesized AlPO-EN3, JDF-2, UiO-12-as, and presumably CFSAPO-1(A). The structure of calcined dehydrated AlPO-53(B) was solved by direct methods, and re®ned to R P 0X084 in Pbca (a 18X0241(1) #

A, b 13X9174(1) # A and c 9X6554(1) # A). The topology of AlPO-53(B), the tetrahedral equivalent of AlPO-EN3, is iso-structural with MCS-1 and UiO-12-500. This topology (structure type code AEN) has two 8-ring channels that intersect to form a 2D system. Heating AlPO 4 -53 to 700°C yields a new condensed phase, . The structure of AlPO-53(C) was solved with the FOCUS program and re®ned to R P 0X124 in C121 with a 16X4440( 4) # A, b 5X1075(1) # A, c 13X4846(4) # A, and b 88X259(1)°. AlPO-53(C) has a new topology described as brw nets in the ac plane, linked by single and double zigzag chains, parallel to b. The elliptical 8-ring pores, parallel to b, produce a 1D channel system. The highly distorted 4-, 6-, and 8-rings in AlPO-53(B) become more regular in AlPO-53(C). The thermal transformation of AlPO-53(B) to AlPO-53(C) is illustrated.