This alternate approach can be useful to detect the 'real' symmetry for a model derived from poor (possibly twinned) data using the same algorithms used to determine the space group from extinctions in observed data (also used by SYSTEM-S).
CALC NEWSYM
or
CALC NEWSYM 0.3
to change the allowed angular error to 0.3 from the default 0.2 Deg.
:: TITL shelxl :: CELL 19.2160 9.6890 18.6810 90.000 102.919 90.000 3390.0 :: SPGR C2/c :: Resd = 1, Z = 4, C36 H46 In2 N4 :: Moiety_Formula C36 H46 In2 N4 :: Formula_Z = 4 :: SpaceGroup_Z = 8 :: Formula_Z' = 0.500 :: mu(MoKa) = 13.9 cm-1 = 1.39 mm-1 NEWSYM - Determine Symmetry from F(calc) data(Resol = 0.60) for: shelx ================================================================================ Analysis of General Reflections for Bravais Centering Nr Ex. Condition < I/sig(I) > Number of Refl I/sigI .T/F. .True. .False. .True. .False. Max.F. H K L Ratio ============================================================================== 1 E HKL:H+K=2N 482.01 0.00 6135 0 0.00 0 0 0 99.0 Possible 2-Fold Axes - 2-Axis Crit = 0.50, Exp. Error = 0.30 Deg., LATT = C ------------------------------------------------------------------------------- Rows Products Angle Between Two Direct Axes Nr D N Direct Recip Dot Delta 1 2 3 4 5 6 7 8 9 -------------------------------------------------------------------------------- 1 9.689 0 1 0 0 2 1 0 2 0.002 0. ==== Transformation Matrix: Input (a,b,c) to Conventional Cell(a', b', c') ==== =============================================================================== (a') ( 1.00 0.00 0.00) (a) (x') ( 1.00 0.00 0.00) (x) Metrically (b') = ( 0.00 1.00 0.00) (b). (y') = ( 0.00 1.00 0.00) (y). monoclinic (c') ( 0.00 0.00 1.00) (c) (z') ( 0.00 0.00 1.00) (z) FOM: 0.002 Latt a b c Alpha Beta Gamma Volume ------------------------------------------------------------------------------- Input Cell C 19.216 9.689 18.681 90.00 102.92 90.00 3390.06 Reduc Cell P 9.689 10.760 18.681 78.48 90.00 63.24 1694.96 Conv. Cell mC 19.216 9.689 18.681 90.00 102.92 90.00 3390.06 Nr Ex. Condition < I/sig(I) > Number of Refl I/sigI .T/F. .True. .False. .True. .False. Max.F. H K L Ratio ============================================================================== 1 E HKL:H+K=2N 482.01 0.00 6135 0 0.00 0 0 0 99.0 7 E 0KL:K=2N 647.04 0.00 190 0 0.00 0 0 0 99.0 10 E H0L:H=2N 929.20 0.00 199 0 0.00 0 0 0 99.0 11 E H0L:L=2N 929.20 0.00 199 0 0.00 0 0 0 99.0 12 E H0L:H+L=2N 929.20 0.00 199 0 0.00 0 0 0 99.0 15 E HK0:H+K=2N 536.69 0.00 380 0 0.00 0 0 0 99.0 16 E H00:H=2N 1475.70 0.00 22 0 0.00 0 0 0 99.0 17 E 0K0:K=2N 701.42 0.00 10 0 0.00 0 0 0 99.0 18 E 00L:L=2N 1209.73 0.00 10 0 0.00 0 0 0 99.0 Candidate Space Groups ====================== L C N Name # AbsFreq StandSet. R(av)% N A/C-Prob ------------------------------------------------------------------------------- SPGR 2 1 1 Cc 9 844 Cc ABC 0.00 2752 39 SPGR 2 2 1 C2/c 15 5965 C2/c ABC 0.00 2752 61