(S)-3,3'-Dibromo-5,5',6,6',7,7',8,8'-octahydro-2,2'-dimeth­oxy-1,1'-binaphthalene

The title compound, C₂₂H₂₄Br₂O₂, consists of two substituted tetra­lin units that are connected through a C-C single bond; the aromatic rings are twisted by 80.2 (2)°.

Key indicators

• Single-crystal X-ray study
• T = 295 K
• Mean [sigma](C-C) = 0.008 Å
• Disorder in main residue
• R factor = 0.045
• wR factor = 0.114
• Data-to-parameter ratio = 17.9

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT220_ALERT_2_A Large Non-Solvent    C     Ueq(max)/Ueq(min) ...       4.63 Ratio

Author Response: The C18 and C19 atoms are probably disordered, but the attempt to treat the disorder (similar to the disorder in the other tetralin unit) by refinining the occupancy gave an impossible value greater than unity.

PLAT241_ALERT_2_A Check High      Ueq as Compared to Neighbors for        C18

Author Response: Sam as above.

Alert level B
PLAT241_ALERT_2_B Check High      Ueq as Compared to Neighbors for        C19

Author Response: Sam as above.

PLAT242_ALERT_2_B Check Low       Ueq as Compared to Neighbors for        C17
PLAT242_ALERT_2_B Check Low       Ueq as Compared to Neighbors for        C20

Alert level C
PLAT062_ALERT_4_C Rescale T(min) & T(max) by .....................       0.96
PLAT222_ALERT_3_C Large Non-Solvent    H     Ueq(max)/Ueq(min) ...       3.59 Ratio
PLAT241_ALERT_2_C Check High      Ueq as Compared to Neighbors for         C9

Author Response: Sam as above.

PLAT241_ALERT_2_C Check High      Ueq as Compared to Neighbors for        C9'

Author Response: Sam as above.

PLAT301_ALERT_3_C Main Residue  Disorder .........................       7.00 Perc.
PLAT341_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ...          8
PLAT720_ALERT_4_C Number of Unusual/Non-Standard Label(s) ........          4
PLAT731_ALERT_1_C Bond    Calc   1.473(11), Rep    1.474(5) ......       2.20 su-Ra
              C17  -C18     1.555   1.555
PLAT731_ALERT_1_C Bond    Calc   1.462(14), Rep    1.462(5) ......       2.80 su-Ra
              C18  -C19     1.555   1.555

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           26.50
           From the CIF: _reflns_number_total               4338
           Count of symmetry unique reflns         2491
           Completeness (_total/calc)            174.15%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured      1847
           Fraction of Friedel pairs measured     0.741
           Are heavy atom types Z>Si present        yes
PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature .        293 K

   2 ALERT level A = In general: serious problem
   3 ALERT level B = Potentially serious problem
   9 ALERT level C = Check and explain
   2 ALERT level G = General alerts; check

   3 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   7 ALERT type 2 Indicator that the structure model may be wrong or deficient
   3 ALERT type 3 Indicator that the structure quality may be low
   3 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

---

Computing details

Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: publCIF (Westrip, 2006).

(S)-3,3'-Dibromo-5,5',6,6',7,7',8,8'-octahydro-2,2'-dimethoxy-1,1'- binaphthalene

Crystal data

C22H24Br2O2	F(000) = 968
Mr = 480.23	Dx = 1.513 Mg m^−3
Orthorhombic, P212121	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 3469 reflections
a = 10.004 (1) Å	θ = 2.3–23.2°
b = 12.086 (1) Å	µ = 3.86 mm^−1
c = 17.434 (2) Å	T = 295 K
V = 2107.9 (4) Å^3	Block, colourless
Z = 4	0.26 × 0.20 × 0.12 mm

Data collection

Bruker SMART 1K area-detector diffractometer	4338 independent reflections
Radiation source: fine-focus sealed tube	2993 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.051
φ and ω scans	θmax = 26.5°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −12→11
Tmin = 0.434, Tmax = 0.655	k = −15→8
11804 measured reflections	l = −20→21

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.045	H-atom parameters constrained
wR(F^2) = 0.114	w = 1/[σ^2(Fo^2) + (0.0603P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 0.96	(Δ/σ)max = 0.001
4338 reflections	Δρmax = 0.61 e Å^−3
242 parameters	Δρmin = −0.34 e Å^−3
23 restraints	Absolute structure: Flack (1983), with 1858 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.01 (2)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Br1	0.34571 (6)	0.65682 (5)	0.07420 (4)	0.0577 (2)
Br2	0.06806 (7)	1.09239 (6)	0.41225 (4)	0.0686 (2)
O1	0.1877 (3)	0.8488 (3)	0.1464 (2)	0.0465 (9)
O2	0.2556 (4)	0.9404 (3)	0.3193 (2)	0.0534 (10)
C1	0.3709 (5)	0.9718 (4)	0.1720 (3)	0.0383 (12)
C2	0.3228 (5)	0.8721 (4)	0.1430 (3)	0.0362 (13)
C3	0.4119 (5)	0.7933 (5)	0.1134 (3)	0.0423 (3)
C4	0.5514 (6)	0.8152 (5)	0.1130 (3)	0.0470 (14)
H4	0.6103	0.7620	0.0945	0.056*
C5	0.6016 (4)	0.9174 (5)	0.1405 (3)	0.0443 (14)
C6	0.5141 (5)	0.9958 (4)	0.1713 (3)	0.0393 (13)
C7	0.5659 (4)	1.1024 (4)	0.2041 (4)	0.0556 (15)
H7C	0.5477	1.1621	0.1684	0.067*	0.37 (1)
H7D	0.5189	1.1185	0.2515	0.067*	0.37 (1)
H7A	0.5115	1.1626	0.1845	0.067*	0.63 (1)
H7B	0.5556	1.1011	0.2594	0.067*	0.63 (1)
C8'	0.7129 (6)	1.0979 (13)	0.2197 (9)	0.070 (4)	0.37 (1)
H8'A	0.7296	1.0508	0.2637	0.084*	0.37 (1)
H8'B	0.7454	1.1715	0.2317	0.084*	0.37 (1)
C9'	0.7864 (11)	1.0536 (8)	0.1513 (11)	0.091 (5)	0.37 (1)
H9'A	0.7632	1.0966	0.1062	0.109*	0.37 (1)
H9'B	0.8819	1.0602	0.1595	0.109*	0.37 (1)
C8	0.7090 (6)	1.1265 (6)	0.1863 (7)	0.070 (4)	0.63
H8A	0.7146	1.1587	0.1354	0.084*	0.63 (1)
H8B	0.7421	1.1808	0.2226	0.084*	0.63 (1)
C9	0.7963 (7)	1.0265 (7)	0.1894 (7)	0.091 (5)	0.63
H9A	0.8864	1.0475	0.1749	0.109*	0.63 (1)
H9B	0.7993	0.9997	0.2418	0.109*	0.63 (1)
C10	0.7507 (4)	0.9348 (5)	0.1385 (4)	0.0632 (18)
H10C	0.7925	0.8898	0.1778	0.076*	0.37 (1)
H10D	0.7851	0.9112	0.0891	0.076*	0.37 (1)
H10A	0.7952	0.8667	0.1532	0.076*	0.63 (1)
H10B	0.7774	0.9524	0.0864	0.076*	0.63 (1)
C11	0.2716 (5)	1.0543 (4)	0.2041 (3)	0.0419 (13)
C12	0.2218 (5)	1.0358 (4)	0.2787 (3)	0.0410 (13)
C13	0.1273 (5)	1.1101 (5)	0.3086 (3)	0.0458 (15)
C14	0.0823 (6)	1.1974 (5)	0.2647 (4)	0.0492 (15)
H14	0.0194	1.2455	0.2853	0.059*
C15	0.1283 (5)	1.2156 (5)	0.1901 (3)	0.0489 (15)
C16	0.2290 (5)	1.1461 (5)	0.1594 (3)	0.0463 (13)
C17	0.2845 (6)	1.1636 (5)	0.0799 (3)	0.0622 (16)
H17A	0.3812	1.1593	0.0824	0.075*
H17B	0.2539	1.1038	0.0473	0.075*
C18	0.2471 (10)	1.2696 (8)	0.0441 (5)	0.168 (6)
H18A	0.3141	1.3241	0.0578	0.201*
H18B	0.2508	1.2603	−0.0111	0.201*
C19	0.1159 (10)	1.3149 (9)	0.0636 (4)	0.157 (5)
H19A	0.0491	1.2750	0.0342	0.188*
H19B	0.1134	1.3914	0.0468	0.188*
C20	0.0759 (7)	1.3116 (6)	0.1452 (3)	0.069 (2)
H20A	−0.0209	1.3106	0.1478	0.083*
H20B	0.1060	1.3793	0.1696	0.083*
C21	0.1145 (5)	0.8788 (5)	0.0780 (4)	0.0606 (17)
H21A	0.0220	0.8601	0.0843	0.091*
H21B	0.1504	0.8394	0.0348	0.091*
H21C	0.1228	0.9570	0.0693	0.091*
C22	0.3771 (7)	0.9458 (7)	0.3620 (4)	0.077 (2)
H22A	0.3925	0.8762	0.3870	0.116*
H22B	0.3707	1.0034	0.3997	0.116*
H22C	0.4500	0.9615	0.3278	0.116*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.0614 (4)	0.0468 (3)	0.0649 (4)	−0.0006 (3)	−0.0027 (3)	−0.0137 (3)
Br2	0.0718 (4)	0.0710 (4)	0.0629 (5)	−0.0048 (4)	0.0262 (4)	−0.0171 (4)
O1	0.0295 (19)	0.061 (2)	0.049 (2)	−0.0021 (19)	0.0018 (16)	−0.001 (2)
O2	0.046 (2)	0.053 (2)	0.061 (3)	−0.003 (2)	0.005 (2)	0.001 (2)
C1	0.034 (3)	0.042 (3)	0.038 (3)	0.007 (2)	0.004 (2)	−0.003 (2)
C2	0.029 (3)	0.043 (3)	0.037 (3)	0.002 (2)	0.005 (2)	0.002 (2)
C3	0.048 (3)	0.044 (3)	0.035 (3)	0.007 (3)	−0.001 (2)	−0.005 (2)
C4	0.041 (3)	0.049 (4)	0.051 (4)	0.011 (3)	0.000 (3)	−0.011 (3)
C5	0.032 (3)	0.056 (4)	0.045 (3)	0.007 (3)	0.000 (2)	−0.003 (3)
C6	0.037 (3)	0.043 (3)	0.038 (3)	0.000 (2)	0.001 (2)	0.001 (2)
C7	0.049 (3)	0.052 (3)	0.066 (4)	−0.005 (3)	0.007 (3)	−0.009 (3)
C8'	0.062 (5)	0.078 (8)	0.069 (9)	−0.027 (5)	0.020 (5)	−0.018 (7)
C9'	0.031 (4)	0.094 (9)	0.147 (15)	0.003 (5)	−0.027 (6)	−0.014 (9)
C8	0.062 (5)	0.078 (8)	0.069 (9)	−0.027 (5)	0.020 (5)	−0.018 (7)
C9	0.031 (4)	0.094 (9)	0.147 (15)	0.003 (5)	−0.027 (6)	−0.014 (9)
C10	0.037 (3)	0.074 (5)	0.078 (5)	0.003 (3)	0.004 (3)	−0.010 (4)
C11	0.040 (3)	0.040 (3)	0.046 (3)	0.003 (3)	0.001 (3)	−0.008 (2)
C12	0.035 (3)	0.037 (3)	0.051 (4)	−0.004 (2)	−0.001 (3)	−0.005 (2)
C13	0.040 (3)	0.051 (4)	0.047 (3)	−0.003 (3)	0.005 (3)	−0.020 (3)
C14	0.035 (3)	0.049 (4)	0.063 (4)	0.006 (3)	0.004 (3)	−0.023 (3)
C15	0.041 (3)	0.045 (3)	0.061 (4)	0.010 (3)	−0.007 (3)	−0.015 (3)
C16	0.039 (3)	0.047 (3)	0.053 (4)	0.002 (3)	−0.001 (3)	−0.007 (3)
C17	0.064 (4)	0.071 (4)	0.051 (4)	0.004 (3)	0.005 (3)	0.005 (4)
C18	0.230 (14)	0.159 (10)	0.114 (8)	0.114 (11)	0.061 (9)	0.076 (8)
C19	0.162 (10)	0.166 (10)	0.142 (10)	0.109 (9)	0.016 (8)	0.067 (8)
C20	0.071 (4)	0.068 (5)	0.068 (5)	0.028 (4)	−0.005 (4)	−0.003 (3)
C21	0.045 (3)	0.073 (4)	0.064 (4)	−0.003 (3)	−0.009 (3)	0.006 (3)
C22	0.068 (5)	0.092 (6)	0.072 (5)	0.003 (4)	−0.013 (4)	0.018 (4)

Geometric parameters (Å, º)

Br1—C3	1.904 (6)	C9—H9A	0.97
Br2—C13	1.914 (6)	C9—H9B	0.97
O1—C2	1.382 (6)	C10—H10C	0.97
O1—C21	1.446 (7)	C10—H10D	0.97
O2—C12	1.394 (6)	C10—H10A	0.97
O2—C22	1.427 (7)	C10—H10B	0.97
C1—C2	1.393 (7)	C11—C12	1.411 (7)
C1—C6	1.461 (7)	C11—C16	1.421 (7)
C1—C11	1.515 (7)	C12—C13	1.404 (7)
C2—C3	1.403 (7)	C13—C14	1.379 (8)
C3—C4	1.420 (8)	C14—C15	1.396 (8)
C4—C5	1.417 (8)	C14—H14	0.93
C4—H4	0.93	C15—C16	1.417 (7)
C5—C6	1.397 (7)	C15—C20	1.495 (8)
C5—C10	1.507 (4)	C16—C17	1.507 (8)
C6—C7	1.503 (4)	C17—C18	1.474 (5)
C7—C8	1.494 (5)	C17—H17A	0.97
C7—C8'	1.497 (5)	C17—H17B	0.97
C7—H7C	0.97	C18—C19	1.462 (5)
C7—H7D	0.97	C18—H18A	0.97
C7—H7A	0.97	C18—H18B	0.97
C7—H7B	0.97	C19—C20	1.477 (5)
C8'—C9'	1.500 (5)	C19—H19A	0.97
C8'—H8'A	0.97	C19—H19B	0.97
C8'—H8'B	0.97	C20—H20A	0.97
C9'—C10	1.496 (5)	C20—H20B	0.97
C9'—H9'A	0.97	C21—H21A	0.96
C9'—H9'B	0.97	C21—H21B	0.96
C8—C9	1.492 (5)	C21—H21C	0.96
C8—H8A	0.97	C22—H22A	0.96
C8—H8B	0.97	C22—H22B	0.96
C9—C10	1.491 (5)	C22—H22C	0.96
C2—O1—C21	114.0 (4)	C5—C10—H10D	109.3
C12—O2—C22	115.7 (5)	H10C—C10—H10D	108.0
C2—C1—C6	120.5 (5)	C9—C10—H10A	109.5
C2—C1—C11	118.5 (4)	C5—C10—H10A	109.2
C6—C1—C11	121.0 (5)	C9—C10—H10B	108.1
O1—C2—C1	119.9 (4)	C5—C10—H10B	109.0
O1—C2—C3	119.9 (5)	H10A—C10—H10B	107.9
C1—C2—C3	120.1 (5)	C12—C11—C16	121.6 (5)
C2—C3—C4	120.0 (5)	C12—C11—C1	117.9 (5)
C2—C3—Br1	120.0 (4)	C16—C11—C1	120.5 (5)
C4—C3—Br1	120.1 (4)	O2—C12—C13	120.3 (5)
C5—C4—C3	120.6 (5)	O2—C12—C11	120.9 (5)
C5—C4—H4	119.7	C13—C12—C11	118.6 (5)
C3—C4—H4	119.7	C14—C13—C12	120.2 (5)
C6—C5—C4	119.9 (4)	C14—C13—Br2	120.6 (4)
C6—C5—C10	122.3 (4)	C12—C13—Br2	119.2 (5)
C4—C5—C10	117.7 (5)	C13—C14—C15	122.0 (5)
C5—C6—C1	118.9 (4)	C13—C14—H14	119.0
C5—C6—C7	120.8 (4)	C15—C14—H14	119.0
C1—C6—C7	120.3 (4)	C14—C15—C16	119.5 (5)
C8—C7—C6	114.8 (4)	C14—C15—C20	119.7 (5)
C8'—C7—C6	112.1 (5)	C16—C15—C20	120.7 (5)
C8'—C7—H7C	109.2	C15—C16—C11	117.9 (5)
C6—C7—H7C	109.2	C15—C16—C17	121.8 (5)
C8'—C7—H7D	109.2	C11—C16—C17	120.2 (5)
C6—C7—H7D	109.2	C18—C17—C16	114.7 (5)
H7C—C7—H7D	107.9	C18—C17—H17A	108.6
C8—C7—H7A	108.6	C16—C17—H17A	108.6
C6—C7—H7A	108.3	C18—C17—H17B	108.6
C8—C7—H7B	108.1	C16—C17—H17B	108.6
C6—C7—H7B	109.1	H17A—C17—H17B	107.6
H7A—C7—H7B	107.7	C19—C18—C17	117.0 (6)
C7—C8'—C9'	110.4 (7)	C19—C18—H18A	108.0
C7—C8'—H8'A	109.6	C17—C18—H18A	108.0
C9'—C8'—H8'A	109.6	C19—C18—H18B	108.0
C7—C8'—H8'B	109.6	C17—C18—H18B	108.0
C9'—C8'—H8'B	109.6	H18A—C18—H18B	107.3
H8'A—C8'—H8'B	108.1	C18—C19—C20	117.2 (5)
C10—C9'—C8'	110.2 (7)	C18—C19—H19A	108.0
C10—C9'—H9'A	109.6	C20—C19—H19A	108.0
C8'—C9'—H9'A	109.6	C18—C19—H19B	108.0
C10—C9'—H9'B	109.6	C20—C19—H19B	108.0
C8'—C9'—H9'B	109.6	H19A—C19—H19B	107.2
H9'A—C9'—H9'B	108.1	C19—C20—C15	115.5 (5)
C9—C8—C7	113.3 (6)	C19—C20—H20A	108.4
C9—C8—H8A	108.9	C15—C20—H20A	108.4
C7—C8—H8A	108.9	C19—C20—H20B	108.4
C9—C8—H8B	108.9	C15—C20—H20B	108.4
C7—C8—H8B	108.9	H20A—C20—H20B	107.5
H8A—C8—H8B	107.7	O1—C21—H21A	109.5
C10—C9—C8	113.7 (6)	O1—C21—H21B	109.5
C10—C9—H9A	108.8	H21A—C21—H21B	109.5
C8—C9—H9A	108.8	O1—C21—H21C	109.5
C10—C9—H9B	108.8	H21A—C21—H21C	109.5
C8—C9—H9B	108.8	H21B—C21—H21C	109.5
H9A—C9—H9B	107.7	O2—C22—H22A	109.5
C9—C10—C5	113.1 (5)	O2—C22—H22B	109.5
C9'—C10—C5	111.5 (5)	H22A—C22—H22B	109.5
C9'—C10—H10C	109.3	O2—C22—H22C	109.5
C5—C10—H10C	109.3	H22A—C22—H22C	109.5
C9—C10—H10D	129.7	H22B—C22—H22C	109.5
C9'—C10—H10D	109.3
C21—O1—C2—C1	93.9 (6)	C6—C5—C10—C9'	−16.3 (11)
C21—O1—C2—C3	−89.0 (6)	C4—C5—C10—C9'	166.5 (9)
C6—C1—C2—O1	177.7 (5)	C2—C1—C11—C12	79.0 (6)
C11—C1—C2—O1	−2.3 (7)	C6—C1—C11—C12	−101.0 (6)
C6—C1—C2—C3	0.6 (8)	C2—C1—C11—C16	−99.9 (6)
C11—C1—C2—C3	−179.4 (5)	C6—C1—C11—C16	80.1 (7)
O1—C2—C3—C4	−177.2 (5)	C22—O2—C12—C13	−99.8 (6)
C1—C2—C3—C4	0.0 (8)	C22—O2—C12—C11	86.3 (6)
O1—C2—C3—Br1	2.6 (7)	C16—C11—C12—O2	174.4 (5)
C1—C2—C3—Br1	179.7 (4)	C1—C11—C12—O2	−4.6 (7)
C2—C3—C4—C5	−1.6 (8)	C16—C11—C12—C13	0.4 (8)
Br1—C3—C4—C5	178.7 (4)	C1—C11—C12—C13	−178.5 (5)
C3—C4—C5—C6	2.6 (8)	O2—C12—C13—C14	−172.3 (5)
C3—C4—C5—C10	179.9 (6)	C11—C12—C13—C14	1.7 (7)
C4—C5—C6—C1	−2.0 (8)	O2—C12—C13—Br2	10.4 (6)
C10—C5—C6—C1	−179.2 (6)	C11—C12—C13—Br2	−175.6 (4)
C4—C5—C6—C7	177.2 (5)	C12—C13—C14—C15	−0.3 (8)
C10—C5—C6—C7	0.0 (9)	Br2—C13—C14—C15	177.0 (4)
C2—C1—C6—C5	0.5 (8)	C13—C14—C15—C16	−3.2 (8)
C11—C1—C6—C5	−179.6 (5)	C13—C14—C15—C20	−180.0 (6)
C2—C1—C6—C7	−178.7 (5)	C14—C15—C16—C11	5.1 (8)
C11—C1—C6—C7	1.3 (8)	C20—C15—C16—C11	−178.2 (5)
C5—C6—C7—C8	12.2 (9)	C14—C15—C16—C17	−178.6 (5)
C1—C6—C7—C8	−168.6 (7)	C20—C15—C16—C17	−1.9 (8)
C5—C6—C7—C8'	−16.3 (11)	C12—C11—C16—C15	−3.8 (8)
C1—C6—C7—C8'	162.8 (9)	C1—C11—C16—C15	175.1 (5)
C8—C7—C8'—C9'	−52.6 (9)	C12—C11—C16—C17	179.8 (5)
C6—C7—C8'—C9'	48.8 (13)	C1—C11—C16—C17	−1.2 (8)
C7—C8'—C9'—C10	−66.8 (14)	C15—C16—C17—C18	12.0 (10)
C6—C7—C8—C9	−39.4 (11)	C11—C16—C17—C18	−171.8 (8)
C7—C8—C9—C10	55.8 (13)	C16—C17—C18—C19	−32.5 (13)
C8—C9—C10—C5	−42.4 (12)	C17—C18—C19—C20	44.0 (15)
C8'—C9'—C10—C5	48.4 (13)	C18—C19—C20—C15	−32.2 (13)
C6—C5—C10—C9	15.1 (10)	C14—C15—C20—C19	−171.8 (8)
C4—C5—C10—C9	−162.2 (7)	C16—C15—C20—C19	11.5 (10)