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</o:shapelayout></xml><![endif]--></head><body lang=EN-GB link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal><span lang=EN-US>Hi, <br>I refining a rhombohedral cell with hexagonal setting and I saw that the a and b cell edges have same value but different sigma. Why ? <br>Davide <br>Reciprocal metric tensor: <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US> names : A11 A22 A33 A12 A13 A23<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US> values: 0.054780220 0.054780220 0.003540059 0.054780220 0.000000000 0.000000000<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US> esds : 0.000002049 0.000000214 <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US> New unit cell:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US> </span><span lang=IT>names : a b c alpha beta gamma Volume<o:p></o:p></span></p><p class=MsoNormal><span lang=IT> </span><span lang=EN-US>values: 4.933527 4.933527 16.807176 90.0000 90.0000 120.0000 354.275<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US> esds : 0.000123 0.000031 0.000508 0.0000 0.0000 0.0005 0.010<o:p></o:p></span></p></div></body></html>