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Acta Cryst. (2011). E67, o507    [ doi:10.1107/S1600536811002388 ]

(22E,24R)-5[alpha]-Ergosta-2,22-dien-6-one

L. Sheng, F. Zeng, F. Chen and C. Xia

Abstract top

In the title molecule, C28H44O, two six-membered rings have regular chair conformations, while the six-membered ring containing the C=C double bond exhibits a distorted chair conformation. The five-membered ring adopts an envelope conformation. In the crystal, weak intermolecular C-H...O interactions link molecules into chains along the b axis. The absolute configuration was assigned to correspond with that of the known chiral centres in a precursor molecule.

Comment top

In continuation of our structural study of brassinolide analogs (Sheng et al., 2011), we present here the crystal structure of the title compound, (I). In (I) (Fig. 1), ring A shows a distorted chair confirmation, and atoms C1, C2, C3 and C4 are coplanar with the r.m.s. deviation of 0.007 (1) Å for the C=C bond; atoms C5 and C10 deviate at 0.329 (4) Å and -0.423 (4) Å from this mean plane, respectively. Rings B and C have regular chair conformation each; while ring D has an envelope conformation. Weak intermolecular C—H···O interactions (Table 1) link the molecules related by translation along the axis b into chains.

Related literature top

For details of the synthesis, see: McMorris et al. (1993). For the crystal structure of the related compound (22E,24R)-3α,5-cyclo-5α-ergosta-22-en-6-one, see: Sheng et al. (2011).

Experimental top

(22E,24R)-5α-Ergosta-2,22-dien-6-one was synthesized as a powder according to the known method (McMorris et al., 1993). Crystals of (I) suitable for structure analysis were obtained by slow evaporation from a mixture of acetone and 95% ethanol (volume proportion, 1:1) as colourless prisms.

Refinement top

C-bound H atoms were placed at calculated positions (C—H 0.95–1.00 Å) and constrained to ride on their parent atoms, withUiso(H) = 1.2-1.5 Ueq(C). Because of negligible anomalous scattering effects, 2305 Friedel pairs were averaged in the refinement. The absolute configuration was assigned to correspond with that of the known chiral centres in a precursor molecule, which remained unchanged during the synthesis of the title compound.

Computing details top

Data collection: CrystalClear (Rigaku/MSC, 2008); cell refinement: CrystalClear (Rigaku/MSC, 2008); data reduction: CrystalClear (Rigaku/MSC, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I) shown with 30% probability displacement ellipsoids.
(22E,24R)-5α-Ergosta-2,22-dien-6-one top
Crystal data top
C28H44OF(000) = 440
Mr = 396.63Dx = 1.100 Mg m−3
Monoclinic, P21Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ybCell parameters from 3421 reflections
a = 9.812 (3) Åθ = 3.2–27.5°
b = 7.578 (2) ŵ = 0.06 mm−1
c = 16.130 (5) ÅT = 123 K
β = 92.832 (4)°Block, colourless
V = 1197.8 (6) Å30.58 × 0.34 × 0.33 mm
Z = 2
Data collection top
Rigaku AFC10/Saturn724+
diffractometer		2598 reflections with I > 2σ(I)
Radiation source: Rotating AnodeRint = 0.030
graphiteθmax = 27.5°, θmin = 3.2°
Detector resolution: 28.5714 pixels mm-1h = −12→12
phi and ω scansk = −9→9
10906 measured reflectionsl = −20→20
2908 independent reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.042Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.091H-atom parameters constrained
S = 1.03 w = 1/[σ2(Fo2) + (0.0346P)2 + 0.296P]
where P = (Fo2 + 2Fc2)/3
2908 reflections(Δ/σ)max < 0.001
268 parametersΔρmax = 0.29 e Å−3
1 restraintΔρmin = −0.14 e Å−3
Crystal data top
C28H44OV = 1197.8 (6) Å3
Mr = 396.63Z = 2
Monoclinic, P21Mo Kα radiation
a = 9.812 (3) ŵ = 0.06 mm−1
b = 7.578 (2) ÅT = 123 K
c = 16.130 (5) Å0.58 × 0.34 × 0.33 mm
β = 92.832 (4)°
Data collection top
Rigaku AFC10/Saturn724+
diffractometer		2598 reflections with I > 2σ(I)
10906 measured reflectionsRint = 0.030
2908 independent reflectionsθmax = 27.5°
Refinement top
R[F2 > 2σ(F2)] = 0.042H-atom parameters constrained
wR(F2) = 0.091Δρmax = 0.29 e Å−3
S = 1.03Δρmin = −0.14 e Å−3
2908 reflectionsAbsolute structure: ?
268 parametersFlack parameter: ?
1 restraintRogers parameter: ?
Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

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 > 2sigma(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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.41104 (19)−0.0462 (3)0.15251 (10)0.0498 (5)
C10.5886 (2)0.5431 (3)0.17436 (13)0.0335 (5)
H1A0.54440.66060.17290.040*
H1B0.65980.54380.22010.040*
C20.6558 (2)0.5130 (4)0.09327 (13)0.0374 (6)
H20.70450.60820.07040.045*
C30.6508 (2)0.3625 (4)0.05232 (13)0.0378 (6)
H30.69400.35620.00100.045*
C40.5807 (2)0.2008 (4)0.08234 (13)0.0377 (6)
H4A0.64140.09750.07680.045*
H4B0.49670.17970.04720.045*
C50.5433 (2)0.2187 (3)0.17289 (12)0.0295 (5)
H50.63030.20820.20750.035*
C60.4516 (2)0.0705 (3)0.19923 (13)0.0332 (5)
C70.4118 (2)0.0762 (3)0.28843 (13)0.0324 (5)
H7A0.49250.04800.32530.039*
H7B0.3416−0.01500.29700.039*
C80.3559 (2)0.2571 (3)0.31218 (12)0.0258 (4)
H80.26480.27420.28260.031*
C90.4513 (2)0.4064 (3)0.28672 (11)0.0243 (4)
H90.54070.38420.31740.029*
C100.4813 (2)0.4025 (3)0.19277 (12)0.0269 (5)
C110.4016 (2)0.5869 (3)0.31708 (12)0.0300 (5)
H11A0.31670.61920.28500.036*
H11B0.47120.67730.30600.036*
C120.3740 (2)0.5889 (3)0.41042 (12)0.0280 (5)
H12A0.46150.57430.44300.034*
H12B0.33520.70470.42500.034*
C130.27536 (19)0.4423 (3)0.43412 (11)0.0232 (4)
C140.3378 (2)0.2678 (3)0.40546 (12)0.0233 (4)
H140.43180.26250.43230.028*
C150.2560 (2)0.1243 (3)0.44678 (14)0.0361 (5)
H15A0.31070.01520.45480.043*
H15B0.17160.09620.41320.043*
C160.2221 (2)0.2060 (3)0.53128 (13)0.0314 (5)
H16A0.27300.14440.57720.038*
H16B0.12320.19600.54000.038*
C170.26526 (19)0.4034 (3)0.52833 (11)0.0220 (4)
H170.35960.41190.55440.026*
C180.1323 (2)0.4742 (4)0.39396 (12)0.0391 (6)
H18A0.13630.46950.33340.059*
H18B0.09940.59060.41040.059*
H18C0.06980.38300.41240.059*
C190.3521 (2)0.4340 (4)0.13685 (12)0.0396 (6)
H19A0.31160.54770.15080.059*
H19B0.28620.33930.14550.059*
H19C0.37610.43490.07860.059*
C200.1723 (2)0.5195 (3)0.57980 (12)0.0261 (4)
H200.07670.50670.55620.031*
C210.2101 (2)0.7153 (3)0.57749 (13)0.0337 (5)
H21A0.15880.77970.61840.051*
H21B0.18760.76270.52200.051*
H21C0.30820.72890.59060.051*
C220.17560 (19)0.4580 (3)0.66901 (11)0.0250 (4)
H220.26250.45010.69740.030*
C230.06861 (19)0.4144 (3)0.71088 (11)0.0257 (4)
H23−0.01760.41470.68130.031*
C240.0705 (2)0.3640 (3)0.80131 (12)0.0247 (4)
H240.16670.37250.82450.030*
C25−0.0184 (2)0.4927 (3)0.85049 (13)0.0304 (5)
H25−0.11560.47670.83030.037*
C26−0.0087 (3)0.4528 (4)0.94378 (13)0.0490 (7)
H26A0.08630.46460.96480.073*
H26B−0.04020.33210.95330.073*
H26C−0.06600.53610.97290.073*
C270.0205 (3)0.6848 (3)0.83604 (15)0.0375 (6)
H27A−0.03530.76190.86940.056*
H27B0.00480.71380.77710.056*
H27C0.11720.70210.85230.056*
C280.0230 (3)0.1728 (3)0.81002 (14)0.0368 (6)
H28A−0.07370.16380.79220.055*
H28B0.03540.13600.86810.055*
H28C0.07690.09610.77530.055*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0724 (12)0.0452 (11)0.0322 (9)−0.0115 (10)0.0075 (8)−0.0167 (8)
C10.0334 (11)0.0418 (14)0.0261 (11)0.0016 (10)0.0079 (9)0.0050 (9)
C20.0312 (11)0.0556 (16)0.0260 (10)0.0020 (11)0.0083 (9)0.0100 (11)
C30.0304 (11)0.0628 (18)0.0207 (10)0.0059 (11)0.0053 (9)0.0023 (10)
C40.0363 (12)0.0549 (16)0.0222 (10)0.0028 (11)0.0063 (9)−0.0067 (10)
C50.0288 (11)0.0409 (13)0.0191 (9)0.0024 (10)0.0025 (8)−0.0039 (9)
C60.0398 (12)0.0349 (13)0.0251 (11)0.0022 (10)0.0033 (9)−0.0066 (9)
C70.0399 (12)0.0311 (12)0.0268 (10)−0.0042 (10)0.0072 (9)−0.0064 (9)
C80.0255 (10)0.0324 (12)0.0197 (9)−0.0005 (9)0.0023 (8)−0.0034 (8)
C90.0236 (9)0.0301 (11)0.0194 (9)0.0024 (9)0.0020 (7)0.0016 (8)
C100.0247 (10)0.0380 (13)0.0183 (9)0.0041 (9)0.0026 (8)0.0001 (8)
C110.0364 (11)0.0296 (12)0.0249 (10)0.0058 (10)0.0104 (9)0.0054 (9)
C120.0358 (11)0.0239 (11)0.0254 (10)0.0026 (9)0.0111 (9)0.0004 (8)
C130.0221 (9)0.0296 (11)0.0181 (8)0.0023 (8)0.0031 (7)−0.0011 (8)
C140.0246 (10)0.0257 (11)0.0200 (9)−0.0045 (8)0.0037 (7)−0.0020 (8)
C150.0452 (13)0.0335 (13)0.0307 (11)−0.0161 (11)0.0128 (10)−0.0080 (10)
C160.0367 (12)0.0320 (13)0.0262 (10)−0.0097 (10)0.0101 (9)−0.0033 (9)
C170.0211 (9)0.0264 (11)0.0185 (9)−0.0014 (8)0.0024 (7)−0.0010 (8)
C180.0277 (11)0.0665 (18)0.0231 (10)0.0095 (11)0.0013 (8)0.0017 (11)
C190.0307 (11)0.0685 (18)0.0196 (9)0.0104 (12)0.0023 (8)0.0052 (11)
C200.0207 (9)0.0364 (12)0.0214 (9)0.0020 (9)0.0030 (7)−0.0001 (9)
C210.0399 (12)0.0331 (12)0.0292 (11)0.0106 (10)0.0110 (9)0.0005 (9)
C220.0227 (9)0.0316 (12)0.0206 (9)0.0008 (9)0.0012 (7)−0.0043 (8)
C230.0254 (10)0.0306 (11)0.0211 (9)0.0010 (9)0.0009 (8)−0.0015 (8)
C240.0233 (10)0.0306 (12)0.0204 (10)−0.0026 (8)0.0026 (8)−0.0008 (8)
C250.0266 (10)0.0385 (13)0.0266 (10)−0.0015 (9)0.0064 (8)−0.0039 (9)
C260.0652 (16)0.0556 (17)0.0278 (11)−0.0009 (15)0.0192 (11)−0.0005 (12)
C270.0403 (13)0.0354 (13)0.0374 (12)0.0047 (10)0.0066 (10)−0.0054 (10)
C280.0439 (14)0.0339 (13)0.0326 (12)−0.0090 (10)0.0021 (10)0.0014 (10)
Geometric parameters (Å, °) top
O1—C61.216 (3)C15—H15A0.9900
C1—C21.511 (3)C15—H15B0.9900
C1—C101.537 (3)C16—C171.556 (3)
C1—H1A0.9900C16—H16A0.9900
C1—H1B0.9900C16—H16B0.9900
C2—C31.318 (4)C17—C201.539 (3)
C2—H20.9500C17—H171.0000
C3—C41.497 (4)C18—H18A0.9800
C3—H30.9500C18—H18B0.9800
C4—C51.529 (3)C18—H18C0.9800
C4—H4A0.9900C19—H19A0.9800
C4—H4B0.9900C19—H19B0.9800
C5—C61.513 (3)C19—H19C0.9800
C5—C101.559 (3)C20—C221.511 (3)
C5—H51.0000C20—C211.530 (3)
C6—C71.510 (3)C20—H201.0000
C7—C81.532 (3)C21—H21A0.9800
C7—H7A0.9900C21—H21B0.9800
C7—H7B0.9900C21—H21C0.9800
C8—C141.526 (3)C22—C231.318 (3)
C8—C91.537 (3)C22—H220.9500
C8—H81.0000C23—C241.507 (3)
C9—C111.540 (3)C23—H230.9500
C9—C101.558 (2)C24—C281.531 (3)
C9—H91.0000C24—C251.552 (3)
C10—C191.538 (3)C24—H241.0000
C11—C121.543 (3)C25—C271.526 (3)
C11—H11A0.9900C25—C261.533 (3)
C11—H11B0.9900C25—H251.0000
C12—C131.534 (3)C26—H26A0.9800
C12—H12A0.9900C26—H26B0.9800
C12—H12B0.9900C26—H26C0.9800
C13—C181.536 (3)C27—H27A0.9800
C13—C141.539 (3)C27—H27B0.9800
C13—C171.556 (2)C27—H27C0.9800
C14—C151.525 (3)C28—H28A0.9800
C14—H141.0000C28—H28B0.9800
C15—C161.548 (3)C28—H28C0.9800
C2—C1—C10113.2 (2)C16—C15—H15A111.0
C2—C1—H1A108.9C14—C15—H15B111.0
C10—C1—H1A108.9C16—C15—H15B111.0
C2—C1—H1B108.9H15A—C15—H15B109.0
C10—C1—H1B108.9C15—C16—C17106.68 (16)
H1A—C1—H1B107.7C15—C16—H16A110.4
C3—C2—C1123.9 (2)C17—C16—H16A110.4
C3—C2—H2118.0C15—C16—H16B110.4
C1—C2—H2118.0C17—C16—H16B110.4
C2—C3—C4123.5 (2)H16A—C16—H16B108.6
C2—C3—H3118.2C20—C17—C13119.12 (16)
C4—C3—H3118.2C20—C17—C16111.31 (16)
C3—C4—C5111.8 (2)C13—C17—C16104.04 (16)
C3—C4—H4A109.3C20—C17—H17107.3
C5—C4—H4A109.3C13—C17—H17107.3
C3—C4—H4B109.3C16—C17—H17107.3
C5—C4—H4B109.3C13—C18—H18A109.5
H4A—C4—H4B107.9C13—C18—H18B109.5
C6—C5—C4112.09 (19)H18A—C18—H18B109.5
C6—C5—C10111.21 (16)C13—C18—H18C109.5
C4—C5—C10112.96 (19)H18A—C18—H18C109.5
C6—C5—H5106.7H18B—C18—H18C109.5
C4—C5—H5106.7C10—C19—H19A109.5
C10—C5—H5106.7C10—C19—H19B109.5
O1—C6—C7121.3 (2)H19A—C19—H19B109.5
O1—C6—C5123.2 (2)C10—C19—H19C109.5
C7—C6—C5115.59 (18)H19A—C19—H19C109.5
C6—C7—C8112.10 (19)H19B—C19—H19C109.5
C6—C7—H7A109.2C22—C20—C21109.17 (18)
C8—C7—H7A109.2C22—C20—C17110.62 (17)
C6—C7—H7B109.2C21—C20—C17112.97 (17)
C8—C7—H7B109.2C22—C20—H20108.0
H7A—C7—H7B107.9C21—C20—H20108.0
C14—C8—C7110.76 (18)C17—C20—H20108.0
C14—C8—C9109.04 (16)C20—C21—H21A109.5
C7—C8—C9111.18 (16)C20—C21—H21B109.5
C14—C8—H8108.6H21A—C21—H21B109.5
C7—C8—H8108.6C20—C21—H21C109.5
C9—C8—H8108.6H21A—C21—H21C109.5
C8—C9—C11111.22 (15)H21B—C21—H21C109.5
C8—C9—C10113.13 (17)C23—C22—C20125.81 (18)
C11—C9—C10113.82 (17)C23—C22—H22117.1
C8—C9—H9106.0C20—C22—H22117.1
C11—C9—H9106.0C22—C23—C24125.98 (18)
C10—C9—H9106.0C22—C23—H23117.0
C1—C10—C19109.40 (19)C24—C23—H23117.0
C1—C10—C9109.81 (17)C23—C24—C28109.84 (17)
C19—C10—C9112.18 (15)C23—C24—C25110.81 (17)
C1—C10—C5107.53 (16)C28—C24—C25111.51 (17)
C19—C10—C5109.67 (19)C23—C24—H24108.2
C9—C10—C5108.13 (16)C28—C24—H24108.2
C9—C11—C12113.11 (18)C25—C24—H24108.2
C9—C11—H11A109.0C27—C25—C26109.5 (2)
C12—C11—H11A109.0C27—C25—C24111.72 (17)
C9—C11—H11B109.0C26—C25—C24111.6 (2)
C12—C11—H11B109.0C27—C25—H25107.9
H11A—C11—H11B107.8C26—C25—H25107.9
C13—C12—C11112.29 (18)C24—C25—H25107.9
C13—C12—H12A109.1C25—C26—H26A109.5
C11—C12—H12A109.1C25—C26—H26B109.5
C13—C12—H12B109.1H26A—C26—H26B109.5
C11—C12—H12B109.1C25—C26—H26C109.5
H12A—C12—H12B107.9H26A—C26—H26C109.5
C12—C13—C18110.85 (19)H26B—C26—H26C109.5
C12—C13—C14106.36 (15)C25—C27—H27A109.5
C18—C13—C14112.21 (18)C25—C27—H27B109.5
C12—C13—C17116.88 (16)H27A—C27—H27B109.5
C18—C13—C17109.92 (15)C25—C27—H27C109.5
C14—C13—C17100.14 (16)H27A—C27—H27C109.5
C15—C14—C8118.85 (17)H27B—C27—H27C109.5
C15—C14—C13104.80 (16)C24—C28—H28A109.5
C8—C14—C13114.15 (17)C24—C28—H28B109.5
C15—C14—H14106.0H28A—C28—H28B109.5
C8—C14—H14106.0C24—C28—H28C109.5
C13—C14—H14106.0H28A—C28—H28C109.5
C14—C15—C16103.90 (17)H28B—C28—H28C109.5
C14—C15—H15A111.0
C10—C1—C2—C3−16.3 (3)C11—C12—C13—C1455.7 (2)
C1—C2—C3—C4−1.6 (4)C11—C12—C13—C17166.48 (17)
C2—C3—C4—C5−12.2 (3)C7—C8—C14—C15−52.7 (3)
C3—C4—C5—C6170.17 (19)C9—C8—C14—C15−175.30 (18)
C3—C4—C5—C1043.6 (2)C7—C8—C14—C13−177.17 (16)
C4—C5—C6—O1−1.4 (3)C9—C8—C14—C1360.2 (2)
C10—C5—C6—O1126.1 (2)C12—C13—C14—C15167.55 (17)
C4—C5—C6—C7178.9 (2)C18—C13—C14—C15−71.1 (2)
C10—C5—C6—C7−53.6 (2)C17—C13—C14—C1545.47 (18)
O1—C6—C7—C8−129.2 (2)C12—C13—C14—C8−60.7 (2)
C5—C6—C7—C850.5 (3)C18—C13—C14—C860.6 (2)
C6—C7—C8—C14−171.04 (17)C17—C13—C14—C8177.18 (16)
C6—C7—C8—C9−49.7 (2)C8—C14—C15—C16−163.18 (19)
C14—C8—C9—C11−52.8 (2)C13—C14—C15—C16−34.2 (2)
C7—C8—C9—C11−175.21 (17)C14—C15—C16—C179.2 (2)
C14—C8—C9—C10177.62 (16)C12—C13—C17—C2082.5 (2)
C7—C8—C9—C1055.2 (2)C18—C13—C17—C20−44.9 (3)
C2—C1—C10—C19−74.4 (2)C14—C13—C17—C20−163.16 (17)
C2—C1—C10—C9162.09 (17)C12—C13—C17—C16−152.84 (18)
C2—C1—C10—C544.7 (2)C18—C13—C17—C1679.7 (2)
C8—C9—C10—C1−174.10 (17)C14—C13—C17—C16−38.54 (18)
C11—C9—C10—C157.7 (2)C15—C16—C17—C20148.14 (17)
C8—C9—C10—C1964.0 (2)C15—C16—C17—C1318.6 (2)
C11—C9—C10—C19−64.2 (2)C13—C17—C20—C22179.15 (17)
C8—C9—C10—C5−57.0 (2)C16—C17—C20—C2258.1 (2)
C11—C9—C10—C5174.73 (17)C13—C17—C20—C21−58.1 (2)
C6—C5—C10—C1172.97 (17)C16—C17—C20—C21−179.16 (18)
C4—C5—C10—C1−60.0 (2)C21—C20—C22—C23110.1 (2)
C6—C5—C10—C19−68.2 (2)C17—C20—C22—C23−125.0 (2)
C4—C5—C10—C1958.9 (2)C20—C22—C23—C24−175.9 (2)
C6—C5—C10—C954.5 (2)C22—C23—C24—C28−116.4 (2)
C4—C5—C10—C9−178.51 (17)C22—C23—C24—C25119.9 (2)
C8—C9—C11—C1251.5 (2)C23—C24—C25—C27−52.4 (2)
C10—C9—C11—C12−179.31 (17)C28—C24—C25—C27−175.10 (19)
C9—C11—C12—C13−54.1 (2)C23—C24—C25—C26−175.45 (19)
C11—C12—C13—C18−66.5 (2)C28—C24—C25—C2661.9 (2)
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C1—H1A···O1i0.992.593.574 (3)173
Symmetry codes: (i) x, y+1, z.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C1—H1A···O1i0.992.593.574 (3)173
Symmetry codes: (i) x, y+1, z.
Acknowledgements top

This project was supported by the Science Foudation for Excellent Youth Scholars of the Department of Education of Zhejiang Province (grant No. G0901116050610). The authors acknowledge Professor Kai-bei Yu at the State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, for the data collection.

references
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