Synthesis and Crystal Structure of the First Fully Characterized Vanadoborate Na3[B6O9(VO4)]

✍ Scribed by M. Touboul; N. Penin; G. Nowogrocki

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 206 KB
• Volume: 150
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1999.8600

✦ Synopsis

Single crystals of synthetic Na 3 VB 6 O 13 were obtained by heating a mixture of Na 2 CO 3 .H 2 O, V 2 O 5 , and H 3 BO 3 ; its formula has been determined by the resolution of the structure from X-ray di4raction data. The compound is orthorhombic, space group P2 1 2 1 2 1 ; the unit cell parameters are a ‫؍‬ 7.723( 7), b ‫؍‬ 10.155(4), c ‫؍‬ 12.505(4) A > , Z ‫؍‬ 4. The crystal structure was solved from 1535 re6ections until R ‫؍‬ 0.029; it contains hexaborate units formed by three triangular BO 3 (3 ) and three tetrahedral BO 4 (3T). These hexaborate groups are joined together to form sheets which are linked by VO 4 tetrahedra leading to a three-dimensional network. The shorthand notation of the vanadoborate ion is 6:R 3 (3 ؉3T)؉VO 4 . The sodium atoms are inside the channels that exist in the compound, whose structural formula may be written Na 3 [B 6 O 9 (VO 4 )]. This compound melts incongruently; powder may be obtained by annealing a mixture of Na 2 B 4 O 7 and V 2 O 5 at 6303C. It is the 5rst vanadoborate for which the formula and the structure have been unambiguously established.