Norbergite
Gibbs G V, Ribbe P H
American Mineralogist 54 (1969) 376-390
The crystal structures of the humite minerals: I. Norbergite
_database_code_amcsd 0000190
4.7104 10.2718 8.7476 90 90 90 Pbnm
atom     x     y     z occ Biso
Mg1  .9890 .6330 .4305      .33
Mg2  .9924 .9077   .25      .38
Si   .4195 .7196   .25      .28
O1   .7617 .7204   .25      .38
O2   .2793 .5740   .25      .32
O3   .2690 .7907 .1034      .32
F    .7295 .9682 .0834  .9  .74
OH   .7295 .9682 .0834  .1  .74