Filling of Channels of the Zeolite Framework in Trigonal Polar Nonaborate Ва 3 Na 0.9 (OH) 1.9 [B 9 O 16 ][B(OH) 3 ]

Crystals of the new trigonal borate Ва 3 Na 0.9 (OH) 1.9 [B 9 O 16 ][B(OH) 3 ] (sp. gr. P 31 c , a = 10.23684(15) Å, c = 8.72926(13) Å) were prepared by the mild hydrothermal synthesis. The filling of the channels in the framework of the polar nonaborate was found to differ from that determined previously. It is consistent with the main features of this structure type with the preservation of sassoline molecules in the channels. The structure contains an additional ОН group, which is involved in the coordination of Ва.