Disordered kalsilite KAlSiO₄

The directionality of (Al,Si)O₄ tetra­hedra within six-membered rings (S6R) could not be defined in disordered kalsilite, i.e. equal probability for U or D directionality [free apex pointing up (U) or down (D)] of (Al,Si)O₄ tetra­hedra is established. In ordered kalsilite, S6R of (Al,Si)O₄ tetra­hedra are characterized with the UDUDUD sequence of the directionality of the tetra­hedra.