12. U Meyer. R Rohner and H Zollinger, Melliand Textilber , 65 (1984) 47 13. T Hori et al., Proc. Korea-Japan Joint Meeting on Fiber Sci. and Techno1

(1983) P93. 14. R Rohner, PhD thesis (ETH Zurich, 1983). 15. N Mataga, Bull. Chem. SOC. Japan, 30 (19571 375. 16. T Hashitani and R Tamamushi, Trans. Faraday SOC., 63 (1967) 369. 17. R H Stokes, J . Amer. Chem. SOC.. 73 (1951) 3527. 18. H Uedaira et al., J . Phys. Chem., 74 (1970) 2211. 19. A Bondi, J. Phys. Chem., 68 (1964) 441 20. H Uedaira and H Uedaira, Bull. Chem Soc Japan, 37 (1964) 1885 21. A Katayama et al., Sen-i Gakkaishi, 21 (1965) 499 22. G Zundel, Angew. Chem. International, Edn, 8 (1969) 499.

REFERENCES 1 H Uedaira and H Uedaira, Bull. Chem. Soc. Japan, 38 (1965) 2192 2 R McGregor, R H Peters and K Varol, J .S D.C, 86 (1970) 437, 442. 3 M Mitsuishi and A Datyner, Sen-i Gakkaishi, 36 (1980) T175. 4 T Hori. M Mizuno and T Shimizu, Colloid Polymer sci., 258 (1980) 1070. 5 T Hori, S lkeoh and T Shimizu, Sen-i Gakkaishi, 38 (1982) T83 b H Uedaira, Bull. Chem Soc. Japan, 46 (1973) 401. 7 J A Albely et al., Trans Faraday SOC., 63 (1967) 360. 8 L G Longthworth, J . Phys. Chem., 67 (1963) 689. 9. E McLauchlin, Chem. Phys., 50 (1964) 1254.

10 C M Gray-Bobo et a l , J. Phys Chem., 73 (1969) 1155. 1 I G Aviv et al., Textilveredlung, 16 (1981) 89.

Crystal data for C.I. Pigment Yellow 10 A Whitaker

Department of Physics, Brunel Uniuersity, Uxbridge, Middlesex UB8 3PH

The single crystal data and X-ray powder pattern are reported for C.I. Pigment Yellow 10[1 -phenyl-3-methyl-4- (2',5'-dichlorophenylazo)-5-pyrazolone]. The powder pattern has been indexed from cell dimensions given by single crystal measurements. The problems of multiple indexing have been reduced by comparing the powder data with observed single crystal intensities.

INTRODUCTION This note is one of a seriesll-31 in which have been reported X-ray powder diffraction data obtained from crushed single crystals, with the aim of providing accurate X-ray data for analytical purposes. One earlier paper [l] examined the usefulness of X-ray powder diffraction to colour chemistry and gave a complete list of articles to that date.

ORIGIN OF SPECIMEN C.I. Pigment Yellow 10 has the molecular structure shown in Figure 1. No X-ray data have been reported on this pigment.

Single crystals were prepared by making a saturated solution of the commercial pigment Hansa Yellow R (HOE) in toluene at 85°C. This was placed in an oven and the temperature increased to 95°C to ensure complete solution and then cooled to room temperature over a period of two and a half weeks.

Figure 1 - C.I. Pigment Yellow 10

OPTICAL EXAMINATION The recrystallisation gave predominantly blade-shaped crystals up to 1.8x0.5x0.3 mm in size, but there were some needle-shaped crystals and also a few massive crystals up to 5 x 3 x 1 mm. Those crystals of sufficient thickness to

270 JSDC Volume 103 July/August 1987

observe the orientation of all three crystallographic axes indicated that the crystal class was triclinic.

The blade-shaped crystals had a monoclinic aspect with a monoclinic angle of about 119". In addition the crystals contained striations (growth lines) parallel to the width of the crystal, and the crystals cleaved easily along these lines. For the purposes of completing the morphological examina- tion a was defined along the length, b across the breadth of the blade and c through the thickness. With this orientation a=94O, p=86" and y=119".

The colour was very variable and was dependent upon thickness; thin crystals were pale yellow, but as the crystals became thicker the colour became darker and more red, the colour changing to yellow-orange (thickness about 0.2 mm), orange (thickness about 0.4 mm), while the thickest crystals (about 1 mm thick) were deep red.

The blade-shaped crystals were pleochroic. When the breadth of the crystals was perpendicular to the plane of polarisation they were slightly redder (typical change yellow to yellowish-orange) compared to when the breadth of the crystal was parallel to the plane of polarisation. These crys- tals exhibited oblique extinction on the blade face with an extinction angle of about 50" from the length in the acute angle of the aspect.

Some of the acicular crystals lay on the same face as the blades and gave the same observations; others gave an almost rectangular aspect (p=86"). Some of these con- tained growth lines passing through the acute angle of the aspect at an angle of 26" to the length. Crystals lying in this way were more obviously pleochroic than blades, the col- our changing from yellow to orange-red as the plane of polarisation was moved from perpendicular to the striations to parallel to them. These crystals also exhibited oblique extinction on the face with an extinction about 50" from the length in the acute angle of the aspect.

TABLE 1

010 9 024 57 011 6860 65

101 5742 16 002 4832 40

011 6359 13 3012

X-ray powder data for C.I. Pigment Yellow 65

' 220 3033 222 3014

113 3 005 . 221 3004

030 3008

9.67 9.05 6.89 6.38 5.76 4.83 4.49

4.37

4.04

3.93

3.80

3.69

3.57

3.452

1.792 '

332 1.794 423 1.792 430 1.789 248 1.784

I 22i 2.796 2.765 02* 3.974 14 2.786 I 3io

zio 3.950 210 3800 } 45 2720 { igi 2728 211 3789 2 721 202 3 698 6 2 667 201 3600 1 2655 1 :$ 2652 121 3568 1 11 038 2645 112 3568 1 2557 321 2557 122 3451 3 104 2493 211 3360

2473 { 320 2471 1 3308b 1 211 3329 1 100 2428 123 2430

1212 3306 I 113 3200 } 320 2362 2372

3189 ' 022 3179 2322 132 2321 2281 014 2290

8 I 232 2.226 I 401 2.213 1

12 402 2.171 312 2.166

2.221 141 2.221 (

2.163

6 2.120 142 2.123

9 2.102 042 2.106

2'082

2'038 { 223 2.036 1 { 223 2.082

240 2.039 6

c)

I242 2.019 1

(322 1.995 1

4

1.923 3

2 2 1.890

b - broad diffuse line

X-RAY EXAMINATION No symmetry was detected on Laue photographs, confirm- ing the triclinic class. Crystals mounted with a, b and c along the rotation axis gave a =9.01 tO.O9A, b =8.94-+0.09A and c=9.88t0.10!1.

The intensity measurements for the crystal structure determination were obtained using an automatic diffracto- meter. This was programmed to give a different unit cell, one in which a, j3 and y were as close to 90" as possible. The density (D,J was obtained by flotation in a mixture of trichloroethylene and carbon tetrachloride, and compared with the density calculated from the unit cell data, D,.

a = 8.879t0.003 A a =95.25-+0.02" b = 9.073t0.002 A p =75.26?0.02" c =10.021-+0.002 A y =94.09+0.02" V=776.5?0.5 A3 D , = 1.485-+0.001 g/cm3

Do = 1.478k0.005 g/cm3

The results of these measurements were:

I 33i 1.931 i24 1.926 015 1.920 204 1.911 422 1.895 214 1.884 015 1.861

6

4

4 3

3

4

3

2

3

3

342 1.838 134 1.837 432 1.836 I 334 1.828

- 1 -

2

3

3

3

2

4

3 4

Space group P1 or Pi.

agreement. The observed and calculated densities are in reasonable

POWDER DATA The X-ray pattern was obtained using an 11.46 cm diam- eter Debye-Scherrer camera and filtered cobalt radation (CoK,,=1.79021 A) and the film photometered. The observed and calculated interplanar spacings and relative intensities are listed in Table 1. The Miller indices given are based on the unit cell from the diffractometer data. The problem of multiple indexing was reduced by reference to the observed single crystal intensities. The patterns of the 'as received' and recystallised samples were in agreement.

REFERENCES 1. A Whitaker, J.S.D.C., 102 (1986) 66. 2. A Whitaker, J.S.D.C., 102 (1986) 109. 3. A Whitaker, J.S.D.C., 102 (1986) 136.

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