Structure of basic sodalite, Na8Al6Si6O24(OH)2.2H2O.

Basic sodalite synthesized at 1.55 GPa total P and 723 K is cubic with a 8.890(1) A, space group P43n, Z = 1, Dcalc. 2.29 g/cm³. The aluminosilicate framework is completely ordered. The cavities are not large enough to allow more than 4 of the 24 cavity O sites to be occupied. Two O atoms per cavity are disordered over sites around <111> directions in such a way that each atom is hydrogen bonded to the other and to one framework O. -J.E.C.