Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane)7.3583 (0.0005) x + 0.7119 (0.0054) y - 3.9201 (0.0047) z = 0.2623 (0.0032)* -0.0009 (0.0010) C1 * -0.0525 (0.0012) C2 * -0.0232 (0.0012) C3 * 0.0267 (0.0012) C3A * 0.0072 (0.0012) C4 * -0.0118 (0.0011) C5 * -0.0169 (0.0010) C6 * 0.0149 (0.0009) C6A * 0.0575 (0.0010) C6A1 * -0.0612 (0.0008) C6B * 0.0602 (0.0010) C9BRms deviation of fitted atoms = 0.03747.3441 (0.0006) x - 1.4269 (0.0094) y - 1.2091 (0.0098) z = 1.2752 (0.0064)Angle to previous plane (with approximate e.s.d.) = 10.52 (0.01)* 0.0010 (0.0006) C6B * -0.0289 (0.0006) C9A * 0.0416 (0.0006) C9 * -0.0370 (0.0006) C8 * 0.0233 (0.0006) C7Rms deviation of fitted atoms = 0.02995.9686 (0.0021) x - 10.0295 (0.0075) y + 2.1998 (0.0091) z = 1.0584 (0.0079)Angle to previous plane (with approximate e.s.d.) = 30.51 (0.04)* -0.0149 (0.0007) C16 * 0.0092 (0.0008) C17 * 0.0028 (0.0009) C18 * -0.0090 (0.0009) C19 * 0.0030 (0.0008) C20 * 0.0090 (0.0008) C21Rms deviation of fitted atoms = 0.0090===========================================================================5.7246 (0.0022) x - 6.2243 (0.0078) y + 8.2177 (0.0079) z = 5.2956 (0.0036)Angle to previous plane (with approximate e.s.d.) = 21.61 (0.05)* 0.0022 (0.0007) C10 * -0.0022 (0.0008) C11 * -0.0003 (0.0008) C12 * 0.0027 (0.0008) C13 * -0.0026 (0.0008) C14 * 0.0002 (0.0008) C15Rms deviation of fitted atoms = 0.00207.3441 (0.0006) x - 1.4269 (0.0094) y - 1.2091 (0.0098) z = 1.2752 (0.0064)Angle to previous plane (with approximate e.s.d.) = 33.50 (0.04)* 0.0010 (0.0006) C6B * -0.0289 (0.0006) C9A * 0.0416 (0.0006) C9 * -0.0370 (0.0006) C8 * 0.0233 (0.0006) C7Rms deviation of fitted atoms = 0.0299- 1.0281 (0.0031) x + 7.1737 (0.0070) y + 17.7236 (0.0033) z = 12.7054 (0.0026)Angle to previous plane (with approximate e.s.d.) = 83.89 (0.04)* -0.0019 (0.0007) C22 * 0.0011 (0.0007) C23 * 0.0018 (0.0007) C24 * -0.0038 (0.0007) C25 * 0.0030 (0.0007) C26 * -0.0001 (0.0007) C27Rms deviation of fitted atoms = 0.00236.5435 (0.0016) x - 8.3888 (0.0073) y - 0.6702 (0.0088) z = 2.5647 (0.0063)Angle to previous plane (with approximate e.s.d.) = 76.93 (0.04)* -0.0148 (0.0007) C28 * 0.0087 (0.0007) C29 * 0.0045 (0.0008) C30 * -0.0117 (0.0008) C31 * 0.0055 (0.0008) C32 * 0.0078 (0.0008) C33Rms deviation of fitted atoms = 0.0095

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.