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Growth of beryllium sulfate tetrahydrate (BST) crystal in hydrate solution
Journal of Crystal Growth 113 (1991) 161—163 North-Holland
161
Growth of beryllium sulfate tetrahydrate (BST) crystal in hydrate solution He Youping, Su Genbo, Pan Feng and Jang Rihong Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, People’s Republic of China
Received 15 March 1991: manuscript received in final form 16 April 1991
The method of solvent evaporation was used to grow BST crystals, and the habits of growth were observed and discussed. The second-harmonic generation (SHG) effects were determined.
It has been reported that beryllium sulfate tetrahydrate (BST), BeSO4’ 4H20, is a potentially useful nonlinear optics material for frequency doubling of high-peak power and high-average power 5321 A radiation due to its transparency and high damage threshold in the UV BST crystals also have a high stability of its phase-matching conditions to local temperature changes in the crystal [1,21. The crystal structure of BST was determined by X-ray methods [3] and by neutron diffraction [4], and its unit cell is tetragonal with a 7.990 A, c 10.688 A and space-group 14c2. Growth of bulk crystals of BST was reported by the method of electrolytic solvent decomposition [5] and by the method of temperature reduction [6] in hydrate solution. In this study, the method of solvent evaporation was used to grow BST crystals, and the habits of growth were observed and discussed. The second-harmonic generation (SHG) effects were also determined. In order to grow the crystal of BeSO 4’ 4H20 by the method of reduction of temperature or evaporation of solvent, the solubility curve was determined as shown in fig. 1. Water was used as the solvent, the nutriant BST had a purity of 99% and the PH value of the solution was 2. From the solubility curve, it is proved that the method of evaporating the solvent is easier to control than that of reduction of temperature. The BST crystals were grown in hydrate solution from their seeds, which had originated from =
spontaneous crystallization or by preparing b-cut 3, by the long rod of seeds, of about 10 x 0.5 atx a10rate mm of was 5 method solvent evaporation, ml/day. The accuracy of temperature control was 0,01°C.About 1000 ml solution were saturated at 46°C, and the rotation rate of the seed-pole was 30 rotations per minute. The crystal shown in fig. 2, has a size of 60 x 43 x 57 mm3, a weight of 42 g and its outline-view with eight faces is shown in fig. 3, which is an example of a successful growth under the above-stated conditions,
=
0022-0248/91/$03.50 © 1991
—
80
60
40
20
00
20
40
60
80 T (°C)
Fig. 1. Solubility curve of BST in water solution.
Elsevier Science Publishers By. (North-Holland)
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He Youping et al. / Growth of beryllium sulfate tetrahydrate in hydrate solution
It was worth noting that the BST crystal exhibited a particular habit of growth under different supersaturation, (a (m m0)/m, where m =
—
and m0 are the solubility in the supersaturation and saturation solutions, respectively). When a = 1.48 x ~ the outline-view of the grown crystal (in fig. 4) was with twelve faces as shown in fig. 5, while, when a = 1.24 X 102, the outline-view of the grown crystal was with eight faces, as shown in fig. 3. The modification of the crystal morphology from twelve faces to eight faces is demonstrated in fig. 6, in which these face indices were determined by X-ray diffraction. Thermal-weight analysis (TWA) of the grown crystal showed that the tetrahydrate (4H20) lost two molecules of water at 117°C, the third hydrate molecule at 214°C, and the last one at 277°C, changing it into the anhydrous BeSO4. Thus the BST crystal is stable at room temperature. On the other hand, the SHG effect of the powder of the BST grown crystal was half of that of NH4H2PO4 (ADP) crystal as measured at 1.06 ~emwave-length of laser pumping. In conclusion, it can be stated that BST crystals with high quality and large size can be grown ideally in a water solution using the method of
163
solvent evaporation. A transparent and optically perfect seed properly selected must be used and the supersaturation value must be carefully controlled. The bulk crystals of BST are stable at room temperature, so that they can be used as active NLO crystal. The particular habits of growth of the BST crystal vary at different values of supersaturation, so that the higher supersaturation, e.g. 1.24 X 10- 2 can be used for fast BST crystal growth with less polyhedral faces. We want to acknowledge the help of Dr. Ling Jiwu, from Fujian Castech Crystals, Inc. (CASTECH), Fuzhou.
References [11G.F.
Dobrzhanskii, M.P. Golovei and G I Kosourov, JETP Letters 10 (1969) 167.
[21K. Kato. Appi. Phys. Letters 33 (1978) 413. [311G. Dance and H.C. Freeman, Acta Cryst. B25 (1969) 304. [4] S.K. Sikka and R. Chidambaram. Acta Cryst. B25 (1969) 310. [51M. Delfino, J. Crystal Growth 32 (1976) 378. [6] M.P. Golovei, G.F. Dobrzhanskii, G.I. Kosourov et al., Kristallografiya 15 (1970) 757.
I I I I
161
Growth of beryllium sulfate tetrahydrate (BST) crystal in hydrate solution He Youping, Su Genbo, Pan Feng and Jang Rihong Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, People’s Republic of China
Received 15 March 1991: manuscript received in final form 16 April 1991
The method of solvent evaporation was used to grow BST crystals, and the habits of growth were observed and discussed. The second-harmonic generation (SHG) effects were determined.
It has been reported that beryllium sulfate tetrahydrate (BST), BeSO4’ 4H20, is a potentially useful nonlinear optics material for frequency doubling of high-peak power and high-average power 5321 A radiation due to its transparency and high damage threshold in the UV BST crystals also have a high stability of its phase-matching conditions to local temperature changes in the crystal [1,21. The crystal structure of BST was determined by X-ray methods [3] and by neutron diffraction [4], and its unit cell is tetragonal with a 7.990 A, c 10.688 A and space-group 14c2. Growth of bulk crystals of BST was reported by the method of electrolytic solvent decomposition [5] and by the method of temperature reduction [6] in hydrate solution. In this study, the method of solvent evaporation was used to grow BST crystals, and the habits of growth were observed and discussed. The second-harmonic generation (SHG) effects were also determined. In order to grow the crystal of BeSO 4’ 4H20 by the method of reduction of temperature or evaporation of solvent, the solubility curve was determined as shown in fig. 1. Water was used as the solvent, the nutriant BST had a purity of 99% and the PH value of the solution was 2. From the solubility curve, it is proved that the method of evaporating the solvent is easier to control than that of reduction of temperature. The BST crystals were grown in hydrate solution from their seeds, which had originated from =
spontaneous crystallization or by preparing b-cut 3, by the long rod of seeds, of about 10 x 0.5 atx a10rate mm of was 5 method solvent evaporation, ml/day. The accuracy of temperature control was 0,01°C.About 1000 ml solution were saturated at 46°C, and the rotation rate of the seed-pole was 30 rotations per minute. The crystal shown in fig. 2, has a size of 60 x 43 x 57 mm3, a weight of 42 g and its outline-view with eight faces is shown in fig. 3, which is an example of a successful growth under the above-stated conditions,
=
0022-0248/91/$03.50 © 1991
—
80
60
40
20
00
20
40
60
80 T (°C)
Fig. 1. Solubility curve of BST in water solution.
Elsevier Science Publishers By. (North-Holland)
I
1111111
(J.~
_ ____ /_-
~~77C’
I
,
//
2.
_~~~~~~:~~~1~’~
J
B
~
~.
a C’ a
~.J
~
9
50
I
He Youping et al. / Growth of beryllium sulfate tetrahydrate in hydrate solution
It was worth noting that the BST crystal exhibited a particular habit of growth under different supersaturation, (a (m m0)/m, where m =
—
and m0 are the solubility in the supersaturation and saturation solutions, respectively). When a = 1.48 x ~ the outline-view of the grown crystal (in fig. 4) was with twelve faces as shown in fig. 5, while, when a = 1.24 X 102, the outline-view of the grown crystal was with eight faces, as shown in fig. 3. The modification of the crystal morphology from twelve faces to eight faces is demonstrated in fig. 6, in which these face indices were determined by X-ray diffraction. Thermal-weight analysis (TWA) of the grown crystal showed that the tetrahydrate (4H20) lost two molecules of water at 117°C, the third hydrate molecule at 214°C, and the last one at 277°C, changing it into the anhydrous BeSO4. Thus the BST crystal is stable at room temperature. On the other hand, the SHG effect of the powder of the BST grown crystal was half of that of NH4H2PO4 (ADP) crystal as measured at 1.06 ~emwave-length of laser pumping. In conclusion, it can be stated that BST crystals with high quality and large size can be grown ideally in a water solution using the method of
163
solvent evaporation. A transparent and optically perfect seed properly selected must be used and the supersaturation value must be carefully controlled. The bulk crystals of BST are stable at room temperature, so that they can be used as active NLO crystal. The particular habits of growth of the BST crystal vary at different values of supersaturation, so that the higher supersaturation, e.g. 1.24 X 10- 2 can be used for fast BST crystal growth with less polyhedral faces. We want to acknowledge the help of Dr. Ling Jiwu, from Fujian Castech Crystals, Inc. (CASTECH), Fuzhou.
References [11G.F.
Dobrzhanskii, M.P. Golovei and G I Kosourov, JETP Letters 10 (1969) 167.
[21K. Kato. Appi. Phys. Letters 33 (1978) 413. [311G. Dance and H.C. Freeman, Acta Cryst. B25 (1969) 304. [4] S.K. Sikka and R. Chidambaram. Acta Cryst. B25 (1969) 310. [51M. Delfino, J. Crystal Growth 32 (1976) 378. [6] M.P. Golovei, G.F. Dobrzhanskii, G.I. Kosourov et al., Kristallografiya 15 (1970) 757.
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