Material name Muscovite
Composition KAl2(Al0.908Si3.092O10)((OH)0.94F0.06)2
Chemical formula weight 398.65
System Monoclinic
Temperature (ºC) 20
a (Å), b (Å), c (Å) 5.1579(9) 8.9505(8) 20.071(5) @
α (deg), β (deg), γ (deg) 90 95.75(2) 90 @
Unit cell volume (Å3) 921.9(3)@@
Calculated density (g/p3) 2.87
Z 4
Space group C2/c (No.15)
atom site g x/a y/b z/c B2)
K 4e 1 0 0.0989(2) 1/4 1.79
Al1 8f 1 0.2509(2) 0.0836(1) 0.00002(5) 0.68
Si1 8f 0.773 0.4649(2) 0.9297(1) 0.13481(5) 0.72
Al2 8f 0.227 0.4649(2) 0.9297(1) 0.13481(5) 0.72
Si2 8f 0.773 0.4516(2) 0.2584(1) 0.13495(5) 0.77
Al3 8f 0.227 0.4516(2) 0.2584(1) 0.13495(5) 0.77
O1 8f 1 0.4133(6) 0.0924(3) 0.1672(1) 1.37
O2 8f 1 0.2521(5) 0.8099(3) 0.1569(1) 1.46
O3 8f 1 0.2517(5) 0.3712(3) 0.1678(1) 1.28
O4 8f 1 0.4618(5) 0.9435(3) 0.0532(1) 0.82
O5 8f 1 0.3843(5) 0.2520(5) 0.0532(1) 0.84
OH 8f 0.94 0.4575(5) 0.5618(3) 0.0499(1) 0.92
F 8f 0.06 0.4575(5) 0.5618(3) 0.0499(1) 0.92

Reference: S. Guggenheim, Y.H. Chang, and A.F. Koster van Groos, American Mineralogist, 72, 537 (1987).