Serandite Jacobsen S D, Smyth J R, Swope R J, Sheldon R I American Mineralogist 85 (2000) 745-752 Two proton positions in the very strong hydrogen bond of serandite, NaMn2[Si3O8(OH)] Sample: neutron _database_code_amcsd 0002431 7.7163 6.9116 6.7368 90.465 94.037 102.844 P-1 atom x y z occ Uiso U(1,1) U(2,2) U(3,3) U(1,2) U(1,3) U(2,3) Na .5557 .2553 .3529 .0080 .0149 .0195 .0000 .0028 .0005 Mn1 .8531 .5945 .1349 .941 .0076 .0070 .0091 .0003 .0007 .0002 Mn2 .8491 .0840 .1329 .983 .0070 .0069 .0087 .0021 .0011 -.0002 Si1 .2151 .4017 .3424 .0046 .0042 .0073 .0012 .0007 -.0001 Si2 .2059 .9511 .3512 .0054 .0042 .0053 .0012 .0004 .0005 Si3 .4543 .7370 .1428 .0040 .0041 .0069 .0010 .0002 -.0005 H1 .1482 .6374 .5498 .842 .0204 .0217 .0211 .0070 .0037 .0009 H2 .1518 .6872 .5483 .158 .015 O1 .6643 .7943 .1138 .0049 .0075 .0136 .0008 .0030 .00008 O2 .3226 .7065 .9435 .0075 .0087 .0092 .0016 -.0015 -.0007 O3 .1788 .4926 .5554 .0105 .0072 .0084 .0035 .0010 -.0014 O4 .1598 .8443 .5572 .0132 .0056 .0075 .0014 .0024 .0015 O5 .0614 .3912 .1671 .0063 .0099 .0071 .0013 -.0001 .0010 O6 .0519 .8912 .1724 .0065 .0077 .0089 .0012 -.0011 -.0007 O7 .4071 .5335 .2772 .0056 .0072 .0145 .0001 .0005 .0042 O8 .3972 .9067 .2866 .0064 .0083 .0133 .0030 .0005 -.0041 O9 .2593 .1888 .3931 .0092 .0032 .0138 .0018 .0005 -.0001