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Crystal data and thermal expansion of tricalciumborate
Mat. R e s . Bull. Vol. 9, pp. 1379-1382, P r i n t e d in the United States.
1974.
Pergamon Press,
Inc.
CRYSTAL DATA AND THERMAL EXPANSION OF TRICALCIUMBORATE J. Mailing, V. Figusch, F. Hanic, V. Wiglasz and J. ~orba Institute of Inorganic Chemistry, Slovak Academy of Sciences, 309 34 3ratislava, Dubravsk~ cesta, Czechoslovakia
( R e c e i v e d May 13, 1974; R e f e r e e d )
ABSTRAC~ingle crystals of tricalcJumborate were grown by the flux method. CazB~O6 crystallizes in the rhombohedral system with the unit cell parameters a~ = 6.3577(7) ~, ~CR = 85.6S(~)°, Z = 2. The equivalent hexagonal lattice parameters are aM= 8.640(I), c , = 11.854(I) X. The anisotropic thermal expansion paremetersd== (1.00 ÷ 0.14)xI0 -~ = (3.60 ~ 0.47)xi0 were determlned by X-ray methods in the temperature interval 25 - I000°C.
lntrodu~[~on TricMciumborate, Ca~Bz06, is a congruently melting compound which undergoes no polymorphic transformation between the room temperature and the melting point (1479 °C) ( I ) . Formally, CasB20~ has been classifield in a common group with orthorhombic Mg33z06, Co3BzOa and Ni33zO6 (2). Recently, this phase became topical in view of the basic refractory materials. It was found that Ca B 0 is compatible with other phases MgO, CaO, MgzSiO~, Ca2SiO~, Ca3MgSi~OJ, CaMgSiO~ (3). Accordingly, i t can precipitate on the grain boundaries. Its thermal properties may influence the behaviour of the refractory materials. An attempt has been made to grow single crystals of Ca33206 by the flux method. From the CaClz flux, single crystals of CazBOsCI were produced, a compound intermediate in the system Ca33~O6-CaCl z (4). The use of the KCl-flux made it possible to prepare single crystals of the reouired phase.
1379
1380
TRICALCIUMBORATE
Vol. 9, No.
I0
Experimental Single crystals of tricalciumborate were prepared by heating a KCl-flux containing 0.1 wt % Ca~B20~ for half an hour at 1020 "C. The flux was cooled within half an hour to 950~C and then, to 770°C, at rate of cooling 5°C/hour. At 770°C, the sam@le was removed from the furnace. Colourless crystals were extracted from the mixture by treatment with water. The identity of crystals was proved by X-ray diffraction methods. Unit cell parameters were obtained from the precession and Weissenberg photographs and refined by least squares from the reflections of the powder pattern (5) (Table I and 2) taken with CuK#(radiation*on Philips 1540 diffractometer (scanning rate I/4 ° 2@/min, internal standard silicon, ao = 5.43035 ~). The powder sample of Ca38206, used both in single crystal growth and in X-ray powder diffraction measurements, was prepared by reaction of CaO and 8203 at 1100 °C for 5 hours with an excess of CaO starting from water solutions of Ca(N03)~ and H3BO3, Unreacted CaO was dissolved from the ignated mixture by ethylene glycole. The high temperature powder patterns were taken with CuK radiation on RigakuDenki heating device attached to the Mikrometa It diffractometer, at a scanning rate 1/2 o 2~/min in the temperature range 25 to I000°C. The sample was readjusted before each of six temperature levels. The temperature was held constant within 2aC. The indexed lines from the interval 27 - 50 2~ were taken for the refinement of the unit cell parameters in each case. The X-ray powder diffraction data at 25°C are given in Table 2. Results and discussion
Crystallographic data on Ca3B20 ~ are summarized in Table I. Conditions limiting possible reflections (-h*k+~ = 3n for hexagonal hkl reflections, ~ = 2n for hO~ reflections) restrict the possible space groups to R3c (C~v) or R~c (D~). According to the measured density D,,~(Table I), the hexagonal unit cell contains eighteen calcium, twelwe boron and thirty six oxygen atoms. From the space group symmetry R3c or R~c and cell content alone (Table I), i t TABLE I follows that twelwe boron atoms are most probably situated on rotation Crystallographic Data for Ca3B20# triads. The physical properties of crystals differ in a,and cM directions. Cell Dimensions a R = 6.3577(7) This clearly follows from Table 3 and ~c~= 85.68(8)' (at 25°C) Fig. I. In the temperature interval aM= 8.640(I) 25 - I000°C, the thermal expansion c, = 11.854(I) coefficients are: c~a = (I .00~0.I 4)xi0- }/aC, Cell Volume V, = 766.33 Xj -3 oCe= (3.60CK).47)x10-~/°C. The direction Calculated Density Dx-- 3.09 gcm Measured Density D.~= 3.10(2) g cm"3 of the maximum expansion is parallel ZM = 6 to the cN axis. Cell Content Probable Space Groups R3c or R~c oCa = (I.00+0.14)xi0"_ The trigonal structure of Ca3B;tO6 Linear Coefficients of Thermal Expansion o(~¢ = (3.60~.O.47)x10"Srepresents a new structural type in the related group of compounds of the composition M~B206(M = Mg, Co, Ni) (6 - 8). The reasonS+this distinction may consist in the difference in ionic radii: Caz+ 0 . ~ ~, . ~ 0.65 ~, Coz* 0.72 ~, Ni 2~ 0.70 X (9)- While the Coz+, Ni2fand MBz+ ions display octahedral coordination, the Caz+ ions tend to increase their coordination number above six. The structure analysis of Ca3B206 is in progress. * ~ = 1.54178
Vol. 9, N o
i0
TRICALCIUk/IBORATE
1381
c. v. x~.~ 8.10 .12.4
V~
cl.
810 800 790 780 770 760
/x ~
+ i "8.9 "1Z3 "1Z2 .12.1
8.6 -12.0 8.5 -//.9 I
I
I
200
4.00
600
I
800
I
1000"C
FIG. 1 Dependence of the Cell Parameters aw and c H and Cell Volume V, of Tricalciumborate on Temperature TABLE 2 X-Rav Powder Diffraction Data for Ca3BzO6 at 25 °C d o@s
deal'
4.643 4.316 2.916 2.756 2.553 2.493 2.1596 2.0444 1.9770 1.9580 1.8949 1.8169 1.7968 1.6987 1.6480 I .6329 1.5489
4.644 4.320 2.915 2.755 2.552 2.494 2.1599 2.0441 1.9757 1.9586 I .8953 1.8169 1.7967 1.6988 1.6488 1.6328 1.5487
(hkl) w
I/Io
dob s
d:~,
012 110 113 104 122 300 220 131 006 312 223 125 116 321 232 410 306
15 15 100 ~5 1 50 25 25 20 10 90 10 10 7 5 3 20
1.4854 1.4575 1.4396 1.3349 1.3123 1.2600 I .2468 1.2051 1.1638 1.1466 1.1360 1.1246 1.0649 1.0645 1.0523 1.041 9
1.4854 1.4578 1 -4399 I .3353 1.3125 I .2599 1.2470 1.2056 1.1637 1.1466 1.1361 I .1245 1.0649 1.0645 1.0527 1.041 8
(hkl ).
t/I o
324 226 330 511 128 119 600 327 336 523 434 229 164
20 7 5 1 3 7 10 3 5 3 1 I I
517 443
3 3
606
TABLE 3 Thermal Expansion of Ca~B206
25 200 400 600 800 1000
8.640(t) 8.655(10) 8.657 ( 2 0 ) 8.691 (13) 8.704 (8) 8.725(7)
11.854(1 ) 11.924(12) 11.980(24) 12.083 (16) 12.270(10 ) 12.270(8)
5
1382
TRICALCIUk'IBORATE
Vol. 9, No. I0
References I. E. T. Carlson, Bur. Stand. J. Research ~.~ 825 (1932). 2. V. V. Kondratyeva, Rent~enometricheskii Opredelitel Boratov. Izd. Nedra
Leningrad (1969). 3. M. I. Taylor, W. F. Ford and J. White, Trans. Brit. Ceram. Soc. 68, 173 (1969). 4. J. Majling, V. Figu~, J. ~orba and F. Hanic, J. AppI. Cryst., submitted for publication. 5. O. Lindkvist and F. Wengelin, Ark. Kemi 28, 179 (1967). 6. J. Pardo, M. Mart~nez-Ripo11 and S. Garcia-B1anco, Anales de Fisica 6_7, 399 (1971). 7. W. Goetz, Naturwissenschaften..5.O, 567 (1963). 8. S. V. Berger, Acta Chem. Scand. I , 660 (1949).
1974.
Pergamon Press,
Inc.
CRYSTAL DATA AND THERMAL EXPANSION OF TRICALCIUMBORATE J. Mailing, V. Figusch, F. Hanic, V. Wiglasz and J. ~orba Institute of Inorganic Chemistry, Slovak Academy of Sciences, 309 34 3ratislava, Dubravsk~ cesta, Czechoslovakia
( R e c e i v e d May 13, 1974; R e f e r e e d )
ABSTRAC~ingle crystals of tricalcJumborate were grown by the flux method. CazB~O6 crystallizes in the rhombohedral system with the unit cell parameters a~ = 6.3577(7) ~, ~CR = 85.6S(~)°, Z = 2. The equivalent hexagonal lattice parameters are aM= 8.640(I), c , = 11.854(I) X. The anisotropic thermal expansion paremetersd== (1.00 ÷ 0.14)xI0 -~ = (3.60 ~ 0.47)xi0 were determlned by X-ray methods in the temperature interval 25 - I000°C.
lntrodu~[~on TricMciumborate, Ca~Bz06, is a congruently melting compound which undergoes no polymorphic transformation between the room temperature and the melting point (1479 °C) ( I ) . Formally, CasB20~ has been classifield in a common group with orthorhombic Mg33z06, Co3BzOa and Ni33zO6 (2). Recently, this phase became topical in view of the basic refractory materials. It was found that Ca B 0 is compatible with other phases MgO, CaO, MgzSiO~, Ca2SiO~, Ca3MgSi~OJ, CaMgSiO~ (3). Accordingly, i t can precipitate on the grain boundaries. Its thermal properties may influence the behaviour of the refractory materials. An attempt has been made to grow single crystals of Ca33206 by the flux method. From the CaClz flux, single crystals of CazBOsCI were produced, a compound intermediate in the system Ca33~O6-CaCl z (4). The use of the KCl-flux made it possible to prepare single crystals of the reouired phase.
1379
1380
TRICALCIUMBORATE
Vol. 9, No.
I0
Experimental Single crystals of tricalciumborate were prepared by heating a KCl-flux containing 0.1 wt % Ca~B20~ for half an hour at 1020 "C. The flux was cooled within half an hour to 950~C and then, to 770°C, at rate of cooling 5°C/hour. At 770°C, the sam@le was removed from the furnace. Colourless crystals were extracted from the mixture by treatment with water. The identity of crystals was proved by X-ray diffraction methods. Unit cell parameters were obtained from the precession and Weissenberg photographs and refined by least squares from the reflections of the powder pattern (5) (Table I and 2) taken with CuK#(radiation*on Philips 1540 diffractometer (scanning rate I/4 ° 2@/min, internal standard silicon, ao = 5.43035 ~). The powder sample of Ca38206, used both in single crystal growth and in X-ray powder diffraction measurements, was prepared by reaction of CaO and 8203 at 1100 °C for 5 hours with an excess of CaO starting from water solutions of Ca(N03)~ and H3BO3, Unreacted CaO was dissolved from the ignated mixture by ethylene glycole. The high temperature powder patterns were taken with CuK radiation on RigakuDenki heating device attached to the Mikrometa It diffractometer, at a scanning rate 1/2 o 2~/min in the temperature range 25 to I000°C. The sample was readjusted before each of six temperature levels. The temperature was held constant within 2aC. The indexed lines from the interval 27 - 50 2~ were taken for the refinement of the unit cell parameters in each case. The X-ray powder diffraction data at 25°C are given in Table 2. Results and discussion
Crystallographic data on Ca3B20 ~ are summarized in Table I. Conditions limiting possible reflections (-h*k+~ = 3n for hexagonal hkl reflections, ~ = 2n for hO~ reflections) restrict the possible space groups to R3c (C~v) or R~c (D~). According to the measured density D,,~(Table I), the hexagonal unit cell contains eighteen calcium, twelwe boron and thirty six oxygen atoms. From the space group symmetry R3c or R~c and cell content alone (Table I), i t TABLE I follows that twelwe boron atoms are most probably situated on rotation Crystallographic Data for Ca3B20# triads. The physical properties of crystals differ in a,and cM directions. Cell Dimensions a R = 6.3577(7) This clearly follows from Table 3 and ~c~= 85.68(8)' (at 25°C) Fig. I. In the temperature interval aM= 8.640(I) 25 - I000°C, the thermal expansion c, = 11.854(I) coefficients are: c~a = (I .00~0.I 4)xi0- }/aC, Cell Volume V, = 766.33 Xj -3 oCe= (3.60CK).47)x10-~/°C. The direction Calculated Density Dx-- 3.09 gcm Measured Density D.~= 3.10(2) g cm"3 of the maximum expansion is parallel ZM = 6 to the cN axis. Cell Content Probable Space Groups R3c or R~c oCa = (I.00+0.14)xi0"_ The trigonal structure of Ca3B;tO6 Linear Coefficients of Thermal Expansion o(~¢ = (3.60~.O.47)x10"Srepresents a new structural type in the related group of compounds of the composition M~B206(M = Mg, Co, Ni) (6 - 8). The reasonS+this distinction may consist in the difference in ionic radii: Caz+ 0 . ~ ~, . ~ 0.65 ~, Coz* 0.72 ~, Ni 2~ 0.70 X (9)- While the Coz+, Ni2fand MBz+ ions display octahedral coordination, the Caz+ ions tend to increase their coordination number above six. The structure analysis of Ca3B206 is in progress. * ~ = 1.54178
Vol. 9, N o
i0
TRICALCIUk/IBORATE
1381
c. v. x~.~ 8.10 .12.4
V~
cl.
810 800 790 780 770 760
/x ~
+ i "8.9 "1Z3 "1Z2 .12.1
8.6 -12.0 8.5 -//.9 I
I
I
200
4.00
600
I
800
I
1000"C
FIG. 1 Dependence of the Cell Parameters aw and c H and Cell Volume V, of Tricalciumborate on Temperature TABLE 2 X-Rav Powder Diffraction Data for Ca3BzO6 at 25 °C d o@s
deal'
4.643 4.316 2.916 2.756 2.553 2.493 2.1596 2.0444 1.9770 1.9580 1.8949 1.8169 1.7968 1.6987 1.6480 I .6329 1.5489
4.644 4.320 2.915 2.755 2.552 2.494 2.1599 2.0441 1.9757 1.9586 I .8953 1.8169 1.7967 1.6988 1.6488 1.6328 1.5487
(hkl) w
I/Io
dob s
d:~,
012 110 113 104 122 300 220 131 006 312 223 125 116 321 232 410 306
15 15 100 ~5 1 50 25 25 20 10 90 10 10 7 5 3 20
1.4854 1.4575 1.4396 1.3349 1.3123 1.2600 I .2468 1.2051 1.1638 1.1466 1.1360 1.1246 1.0649 1.0645 1.0523 1.041 9
1.4854 1.4578 1 -4399 I .3353 1.3125 I .2599 1.2470 1.2056 1.1637 1.1466 1.1361 I .1245 1.0649 1.0645 1.0527 1.041 8
(hkl ).
t/I o
324 226 330 511 128 119 600 327 336 523 434 229 164
20 7 5 1 3 7 10 3 5 3 1 I I
517 443
3 3
606
TABLE 3 Thermal Expansion of Ca~B206
25 200 400 600 800 1000
8.640(t) 8.655(10) 8.657 ( 2 0 ) 8.691 (13) 8.704 (8) 8.725(7)
11.854(1 ) 11.924(12) 11.980(24) 12.083 (16) 12.270(10 ) 12.270(8)
5
1382
TRICALCIUk'IBORATE
Vol. 9, No. I0
References I. E. T. Carlson, Bur. Stand. J. Research ~.~ 825 (1932). 2. V. V. Kondratyeva, Rent~enometricheskii Opredelitel Boratov. Izd. Nedra
Leningrad (1969). 3. M. I. Taylor, W. F. Ford and J. White, Trans. Brit. Ceram. Soc. 68, 173 (1969). 4. J. Majling, V. Figu~, J. ~orba and F. Hanic, J. AppI. Cryst., submitted for publication. 5. O. Lindkvist and F. Wengelin, Ark. Kemi 28, 179 (1967). 6. J. Pardo, M. Mart~nez-Ripo11 and S. Garcia-B1anco, Anales de Fisica 6_7, 399 (1971). 7. W. Goetz, Naturwissenschaften..5.O, 567 (1963). 8. S. V. Berger, Acta Chem. Scand. I , 660 (1949).