AM_Phase-X_2 Formula: Si2 Mg1.84 Al.06 Cr.02 K6 O7 Name: Phase-X Unit cell: 5.028 5.028 13.216 90.0 90.0 120.0 , V=289.35 Space group: P63CM (185)

Mancini F , Harlow G E , Cahill C L , American Mineralogist , 87 (2002) p.302-306, The crystal structure and cation ordering of phase-X -, (K1-x-n)2(Mg1-n[Al,Cr]n)2Si2O7H2x: A potential K- and H-bearing, phase in the mantle