Compound strontium fluoroborate and strontium fluoroborate nonlinear optical crystal, and preparation methods and uses thereof

Abstract

A compound strontium fluoroborate, nonlinear optical crystal of strontium fluoroborate, preparation method thereof; the chemical formula of the compound is SrB5O7F3, its molecular weight is 310.67, and it is prepared by solid-state reaction; the chemical formula of the crystal is SrB5O7F3, its molecular weight is 310.67, the crystal is of the orthorhombic series, the space group is Ccm21, and the crystal cell parameters are=10.016(6) Å, b=8.654(6)(4) Å, c=8.103(5) Å, Z=4, and V=702.4(8) Å3. A SrB5O7F3 nonlinear optical crystal has uses in the preparation of a harmonic light output when doubling, tripling, quadrupling, quintupling, or sextupling the frequency of a 1064-nm fundamental-frequency light outputted by a Nd:YAG laser, or the generation of a deep-ultraviolet frequency doubling light output lower than 200 nm, or in the preparation of a frequency multiplier, upper or lower frequency converter, or an optical parametric oscillator.

Claims

1. A compound strontium fluoroborate, wherein the compound has a chemical formula of SrB.sub.5O.sub.7F.sub.3 with a molecular weight of 310.67, and is prepared via a solid-phase reaction method.

2. The compound strontium fluoroborate according to claim 1, wherein the compound is prepared in the following steps: homogeneously mixing an Sr-containing compound which is Sr(BF.sub.4).sub.2, B-containing compounds which are H.sub.3BO.sub.3 and B.sub.2O.sub.3, and an F-containing compound which is Sr(BF.sub.4).sub.2 at a molar ratio of Sr:B:F=0.5-2:5-7:2-4, adding the mixture into a hydrothermal reactor or a quartz tube for sealing, placing the hydrothermal reactor or the quartz tube into a resistance furnace, heating at a rate of 10-30° C./h to 180-620° C. for 10-48 h, then cooling at a rate of 1-10° C./h to 25° C., and opening the hydrothermal reactor or the quartz tube to give the compound SrB.sub.5O.sub.7F.sub.3.

3. A strontium fluoroborate nonlinear optical crystal, wherein the crystal has a chemical formula of SrB.sub.5O.sub.7F.sub.3 with a molecular weight of 310.67, the crystal belongs to the orthorhombic crystal system with the space group of Cmc2.sub.1, and has cell parameters as follows: a=10.016(6) Å, b=8.654(6)(4) Å, c=8.103(5) Å, Z=4, V=702.4(8) Å.sup.3.

4. A method for preparing the strontium fluoroborate nonlinear optical crystal according to claim 3, wherein the crystals are grown by means of a flux method, a Bridgman-Stockbarger method, a room-temperature solution method or a solvothermal method; the flux method for growing the strontium fluoroborate nonlinear optical crystal is particularly carried out in the following steps: a, homogeneously mixing an Sr-containing compound which is Sr(BF.sub.4).sub.2, B-containing compounds which are H.sub.3BO.sub.3 and B.sub.2O.sub.3, and an F-containing compound which is Sr(BF.sub.4).sub.2 at a molar ratio of Sr:B:F=0.5-2:5-7:2-4, adding the mixture into a hydrothermal reactor or a quartz tube for sealing, placing the hydrothermal reactor or the quartz tube into a resistance furnace, heating at a rate of 10-30° C./h to a temperature of 180-620° C., keeping the temperature for 10-48 h, then cooling at a rate of 1-10° C./h to 25° C., and opening the hydrothermal reactor or the quartz tube to give the compound SrB.sub.5O.sub.7F.sub.3; b, adding the resultant compound SrB.sub.5O.sub.7F.sub.3 into a quartz tube of Φ10 mm, vacuumizing the quartz tube to a vacuum degree of 1×10.sup.−3 Pa, performing vacuum packaging with a flamer, placing the quartz tube into a muffle furnace, heating at a rate of 10-30° C./h to a temperature of 200-650° C., keeping the temperature for 12-60 h, then cooling at a rate of 1-5° C./h to 25° C., and opening the quartz tube to give a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal; c, placing the seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal obtained in step b on the bottom of a container which is a quartz tube, then mixing the compound SrB.sub.5O.sub.7F.sub.3 obtained in step a with a flux which is NaF, NaBF.sub.4, NaF—H.sub.3BO.sub.3, NaF—B.sub.2O.sub.3, H.sub.3BO.sub.3 or B.sub.2O.sub.3 at a molar ratio of 1:1-5, placing the mixture into the quartz tube, vacuumizing the quartz tube to a vacuum degree of 1×10.sup.−3 Pa, and performing vacuum packaging with a flamer; and d, sealing the container in step c or adding 10-100 mL of solvent which is deionized water, anhydrous ethanol, or hydrofluoric acid for re-sealing, placing the container into a resistance furnace, heating at a rate of 20-40° C./h to a temperature of 150-650° C., keeping the temperature for 12-60 h, cooling at a rate of 1-3° C./day to 50° C., further cooling at a rate of 1-10° C./h to 25° C., and opening the container to give an SrB.sub.5O.sub.7F.sub.3 crystal with a dimension of 1-20 mm; the Bridgman-Stockbarger method for growing the strontium fluoroborate nonlinear optical crystal is particularly carried out in the following steps: a, homogeneously mixing an Sr-containing compound which is Sr(BF.sub.4).sub.2, B-containing compounds which are H.sub.3BO.sub.3 and B.sub.2O.sub.3, an F-containing compound which is Sr(BF.sub.4).sub.2 at a molar ratio of Sr:B:F=0.5-2:5-7:2-4, adding the mixture into a hydrothermal reactor or a quartz tube for sealing, placing the hydrothermal reactor or the quartz tube into a resistance furnace, heating at a rate of 10-30° C./h to a temperature of 180-620° C., keeping the temperature for 10-48 h, then cooling at a rate of 1-10° C./h to 25° C., and opening the hydrothermal reactor or the quartz tube to give the compound SrB.sub.5O.sub.7F.sub.3; b, adding the resultant compound SrB.sub.5O.sub.7F.sub.3 into the hydrothermal reactor for sealing, placing the hydrothermal reactor into a drying oven, heating at a rate of 20° C./h to a temperature of 200° C., keeping the temperature for 10 h, then cooling at a rate of 1° C./h to 25° C., and opening the hydrothermal reactor to give a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal; c, placing the resultant seed crystal on the bottom of an iridium crucible, then adding the resultant compound SrB.sub.5O.sub.7F.sub.3 into the iridium crucible; and d, sealing the iridium crucible and placing it into a crucible descending furnace, heating to a temperature of 350-600° C., keeping the temperature for 10-20 h, adjusting the position of the container to allow the temperature of spontaneous nucleation or seeding to be 350-600° C., and slowly descending the container at a rate of 0.05-2 mm/h while keeping the growth temperature constant or slowly cooling at a rate of 0-3° C./h, after the completion of growth, cooling the growth furnace to 25° C., removing the container to give an SrB.sub.5O.sub.7F.sub.3 crystal with a dimension of 1-20 mm; the room-temperature solution method for growing the strontium fluoroborate nonlinear optical crystal is particularly carried out in the following steps: a, homogeneously mixing an Sr-containing compound which is Sr(BF.sub.4).sub.2, B-containing compounds which are H.sub.3BO.sub.3 and B.sub.2O.sub.3, an F-containing compound which is Sr(BF.sub.4).sub.2 at a molar ratio of Sr:B:F=0.5-2:5-7:2-4, adding the mixture into a hydrothermal reactor or a quartz tube for sealing, placing the hydrothermal reactor or the quartz tube into a resistance furnace, heating at a rate of 10-30° C./h to a temperature of 180-620° C., keeping the temperature for 10-48 h, then cooling at a rate of 1-10° C./h to 25° C., and opening the hydrothermal reactor or the quartz tube to give the compound SrB.sub.5O.sub.7F.sub.3; b, adding the compound SrB.sub.5O.sub.7F.sub.3 obtained in step a into the hydrothermal reactor for sealing, placing the hydrothermal reactor into a drying oven, heating at a rate of 10-30° C./h to a temperature of 200-600° C., keeping the temperature for 10-48 h, then cooling at a rate of 1-5° C./h to 25° C., and opening the hydrothermal reactor or the quartz tube to give a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal; c, placing the seed crystal obtained in step b on the bottom of a cleaned container, then adding the resultant compound SrB.sub.5O.sub.7F.sub.3 into the container; and d, adding 10-100 mL of solvent which is deionized water, anhydrous ethanol or hydrofluoric acid into the container in step c, which is then subjected to an ultrasonic treatment for sufficient mixing and dissolution, adjusting the pH of the solution to 1-11, filtering the mixture with a qualitative filter paper, encapsulating the container with a PVC film, placing the container in a static environment without shaking, contamination, or air convection, piercing and forming several holes in the seal to adjust the evaporation rate of the solvent in the solution, standing at room temperature, and after the completion of growth, giving an SrB.sub.5O.sub.7F.sub.3 crystal with a dimension of 1-20 mm; the solvothermal method for growing the strontium fluoroborate nonlinear optical crystal is particularly carried out in the following steps: a, homogeneously mixing an Sr-containing compound which is Sr(BF.sub.4).sub.2, B-containing compounds which are H.sub.3BO.sub.3 and B.sub.2O.sub.3, an F-containing compound which is Sr(BF.sub.4).sub.2 at a molar ratio of Sr:B:F=0.5-2:5-7:2-4, adding the mixture into a hydrothermal reactor or a quartz tube for sealing, placing the hydrothermal reactor or the quartz tube into a resistance furnace, heating at a rate of 10-30° C./h to a temperature of 180-620° C., keeping the temperature for 10-48 h, then cooling at a rate of 1-10° C./h to 25° C., and opening the hydrothermal reactor or the quartz tube to give the compound SrB.sub.5O.sub.7F.sub.3; b, adding the compound SrB.sub.5O.sub.7F.sub.3 obtained in step a into the hydrothermal reactor for sealing, placing the hydrothermal reactor into a drying oven, heating at a rate of 10-30° C./h to a temperature of 200-600° C., keeping the temperature for 10-48 h, then cooling at a rate of 1-5° C./h to 25° C., and opening the hydrothermal reactor or the quartz tube to give a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal; c, placing the seed crystal obtained in step b on the bottom of PTFE lining of a clean and non-contaminated hydrothermal reactor with a volume of 23 mL, then adding the resultant compound SrB.sub.5O.sub.7F.sub.3 into the PTFE lining; and d, adding into the PTFE lining a solvent which is deionized water, and sealing the hydrothermal reactor; placing the hydrothermal reactor into a drying oven, heating at a rate of 20° C./h to a temperature of 150° C., keeping the temperature for 24 h, cooling at a rate of 2° C./day to 130° C., and then cooling at a rate of 2° C./h to 25° C., and opening the hydrothermal reactor to give the SrB.sub.5O.sub.7F.sub.3 crystal.

5. The method for preparing the strontium fluoroborate nonlinear optical crystal according to claim 4, wherein in step c of the flux method, the NaF—H.sub.3BO.sub.3 flux system comprises NaF and H.sub.3BO.sub.3 at a molar ratio of 1-3:1-5; and the NaF—B.sub.2O.sub.3 system comprises NaF and B.sub.2O.sub.3 at a molar ratio of 1-2:1-4.

6. A method for producing 2nd, or 3rd, or 4th, or 5th, or 6th harmonic light output based on a fundamental frequency light output of 1064 nm from a Nd:YAG laser, comprising applying a light source with an incident wavelength of 1064 nm from a Nd:YAG laser to the strontium fluoroborate nonlinear optical crystal according to claim 3.

7. A method for producing deep ultraviolet harmonic light output below 200 nm, comprising applying a light source to the strontium fluoroborate nonlinear optical crystal according to claim 3.

8. A method for preparing a harmonic generator, an up-and-down frequency converter, or an optical parametric-oscillator, comprising forming the harmonic generator, the up-and-down frequency converter, or the parametric-oscillator from the strontium fluoroborate nonlinear optical crystal according to claim 3.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a powder XRD spectrum of the compound SrB.sub.5O.sub.7F.sub.3 of the present invention. The spectrum is consistent with the theoretical XRD spectrum, indicating the existence of the compound SrB.sub.5O.sub.7F.sub.3;

(2) FIG. 2 is a working principle diagram of a nonlinear optical device made from the SrB.sub.5O.sub.7F.sub.3 crystal of the present invention, wherein 1 represents a laser, 2 represents an incident light beam, 3 represents an SrB.sub.5O.sub.7F.sub.3 crystal, 4 represents an emission light beam, and 5 represents a filter.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Example 1

(3) Preparation of the Compound:

(4) The compound SrB.sub.5O.sub.7F.sub.3 was synthesized by a solid-phase reaction method according to the equation of 3Sr(BF.sub.4).sub.2+7B.sub.2O.sub.3.fwdarw.3SrB.sub.5O.sub.7F.sub.3+5BF.sub.3↑.

(5) Sr(BF.sub.4).sub.2 and B.sub.2O.sub.3 were homogeneously mixed at a molar ratio of 3:7. The mixture was added into a quartz tube of Φ10 mm. The quartz tube was vacuumized to a vacuum degree of 1×10.sup.−3 Pa, and subjected to vacuum packaging with a flamer. The quartz tube was placed into a muffle furnace, and heated at a rate of 30° C./h to 600° C. for 12 h. Then, the quartz tube was cooled at a rate of 6° C./h to 25° C., and opened to give the compound SrB.sub.5O.sub.7F.sub.3.

Example 2

(6) Preparation of the Compound:

(7) The compound SrB.sub.5O.sub.7F.sub.3 was synthesized by a solid-phase reaction method according to the equation of 3Sr(BF.sub.4).sub.2+14H.sub.3BO.sub.3.fwdarw.3SrB.sub.5O.sub.7F.sub.3+5BF.sub.3↑+21H.sub.2O↑:

(8) Sr(BF.sub.4).sub.2 and H.sub.3BO.sub.3 were homogeneously mixed at a molar ratio of 3:14, and added into the PTFE lining of a clean and non-contaminated hydrothermal reactor with a volume of 23 mL. The hydrothermal reactor was tightly sealed, placed in a drying oven, heated at a rate of 35° C./h to 200° C. for 60 h, then cooled at a rate of 6° C./h to 25° C., and opened to give the compound SrB.sub.5O.sub.7F.sub.3.

Example 3

(9) Synthesis of the SrB.sub.5O.sub.7F.sub.3 nonlinear optical crystal by a room-temperature solution method:

(10) The SrB.sub.5O.sub.7F.sub.3 compound was synthesized according to the equation of 3Sr(BF.sub.4).sub.2+7B.sub.2O.sub.3.fwdarw.3SrB.sub.5O.sub.7F.sub.3+5BF.sub.3↑. The particular operation steps are similar to those in EXAMPLE 1.

(11) The resultant compound SrB.sub.5O.sub.7F.sub.3 was added into a hydrothermal reactor for sealing. The hydrothermal reactor was placed into a drying oven, heated at a rate of 20° C./h to 200° C. for 10 h, then cooled at a rate of 1° C./h to 25° C., and opened to give a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal.

(12) The resultant seed crystal was placed on the bottom of a cleaned beaker, and then the resultant compound SrB.sub.5O.sub.7F.sub.3 was added into the beaker. To the beaker was added 5 mL of solvent hydrofluoric acid. Then, the mixture was subjected to an ultrasonic treatment for sufficient mixing and dissolution. The pH of the solution was adjusted to 4-6, and the solution was filtered with a qualitative filter paper. The container was encapsulated with a PVC film, and placed in a static environment without shaking, contamination, or air convection. The sealing film was pierced with several holes to adjust the evaporation rate of the solvent in the solution, and then the solution stood at room temperature, after the completion of growth, an SrB.sub.5O.sub.7F.sub.3 crystal with a dimension of Φ3 mm×4 mm×5 mm was obtained.

Example 4

(13) Synthesis of the SrB.sub.5O.sub.7F.sub.3 nonlinear optical crystal by a room-temperature solution method:

(14) The SrB.sub.5O.sub.7F.sub.3 compound was synthesized according to the equation of 3Sr(BF.sub.4).sub.2+14H.sub.3BO.sub.3.fwdarw.3SrB.sub.5O.sub.7F.sub.3+5BF.sub.3↑+21H.sub.2O↑. The particular operation steps are similar to those in EXAMPLE 1.

(15) The resultant compound SrB.sub.5O.sub.7F.sub.3 was added into a quartz tube of Φ10 mm which was vacuumized to a vacuum degree of 1×10.sup.−3 Pa, and vacuum packaging was performed with a flamer. The quartz tube was placed into a muffle furnace, heated at a rate of 40° C./h to 600° C. for 48 h, then cooled at a rate of 5° C./h to 25° C., and opened to give a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal.

(16) The resultant seed crystal was placed on the bottom of the container, and then the resultant compound SrB.sub.5O.sub.7F.sub.3was placed into the conical flask.

(17) To the conical flask was added 100 mL of anhydrous ethanol. Then, the mixture was subjected to an ultrasonic treatment for sufficient mixing and dissolution, and filtered with a qualitative filter paper. The container was encapsulated with a PVC film, and placed in a static environment without shaking, contamination, or air convection. The sealing film was pierced with several holes to adjust the evaporation rate of the solvent in the solution, and the solution stood at room temperature. After the completion of growth, an SrB.sub.5O.sub.7F.sub.3 crystal with a dimension of Φ5 mm×2 mm×3 mm was obtained.

Example 5

(18) Growth of SrB.sub.5O.sub.7F.sub.3crystal by a room-temperature solution method:

(19) The SrB.sub.5O.sub.7F.sub.3 compound was synthesized according to the equation of 3Sr(BF.sub.4).sub.2+14H.sub.3BO.sub.3.fwdarw.3SrB.sub.5O.sub.7F.sub.3+5BF.sub.3↑+21H.sub.2O↑. The particular operation steps are similar to those in EXAMPLE 2.

(20) The resultant compound SrB.sub.5O.sub.7F.sub.3 was added into the hydrothermal reactor for sealing. The hydrothermal reactor was placed into a drying oven, heated at a rate of 30° C./h to 280° C. for 20 h, then cooled at a rate of 2° C./h to 25° C., and the hydrothermal reactor was opened to give a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal.

(21) The resultant seed crystal was placed on the bottom of the beaker, and then the compound SrB.sub.5O.sub.7F.sub.3 obtained in step a was added into the beaker.

(22) To the beaker was added deionized water. The mixture was then subjected to an ultrasonic treatment for sufficient mixing and dissolution, and filtered with a qualitative filter paper. The container was encapsulated with a PVC film, and placed in a static environment without shaking, contamination, or air convection. The sealing film was pierced with several holes to adjust the evaporation rate of the solvent in the solution. The solution stood at room temperature. After the completion of growth, an SrB.sub.5O.sub.7F.sub.3 crystal with a dimension of Φ6 mm×6 mm×5 mm was obtained.

Example 6

(23) Growth of SrB.sub.5O.sub.7F.sub.3 crystal by a flux method:

(24) The SrB.sub.5O.sub.7F.sub.3 compound was synthesized according to the equation of 3Sr(BF.sub.4).sub.2+7B.sub.2O.sub.3.fwdarw.3SrB.sub.5O.sub.7F.sub.3+5BF.sub.3↑. The particular operation steps are similar to those in EXAMPLE 2.

(25) The resultant compound SrB.sub.5O.sub.7F.sub.3 was added into a quartz tube of Φ10 mm which was vacuumized to a vacuum degree of 1×10.sup.−3 Pa, and the quartz tube was subjected to vacuum packaging with a flamer. The quartz tube was placed into a muffle furnace, heated at a rate of 30° C./h to 400° C. for 30 h, then cooled at a rate of 2° C./h to 25° C., and the quartz tube was opened to give a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal.

(26) The resultant SrB.sub.5O.sub.7F.sub.3 seed crystal was placed on the bottom of the container, and then the resultant compound SrB.sub.5O.sub.7F.sub.3 was mixed with a flux which was NaF at a molar ratio of 1:5. The mixture was placed into the quartz tube, the quartz tube was vacuumized to a vacuum degree of 1×10.sup.−3 Pa, and subjected to vacuum packaging with a flamer.

(27) Then, the quartz tube was placed into a muffle furnace, heated at a rate of 30° C./h to 500° C. for 36 h, then cooled at a rate of 1.5° C./day to 450° C. and then cooled at a rate of 2° C./h to 25° C. The quartz tube was cut to give an SrB.sub.5O.sub.7F.sub.3 crystal with a dimension of Φ5 mm×5 mm×5 mm.

Example 7

(28) Growth of SrB.sub.5O.sub.7F.sub.3 crystal by a flux method:

(29) The SrB.sub.5O.sub.7F.sub.3 compound was synthesized according to the equation of 3Sr(BF.sub.4).sub.2+7B.sub.2O.sub.3.fwdarw.3SrB.sub.5O.sub.7F.sub.3+5BF.sub.3↑. The particular operation steps are similar to those in EXAMPLE 1.

(30) The resultant compound SrB.sub.5O.sub.7F.sub.3 was added into a quartz tube of Φ10 mm. The quartz tube was vacuumized to a vacuum degree of 1×10.sup.−3 Pa, and subjected to vacuum packaging with a flamer. The quartz tube was placed into a muffle furnace, heated at a rate of 20° C./h to 300° C. for 10 h, then cooled at a rate of 1° C./h to 25° C., and the quartz tube was opened to give a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal.

(31) First, a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal was placed on the bottom of a quartz tube of Φ10 mm. Then the compound SrB.sub.5O.sub.7F.sub.3 was mixed with a flux NaF:H.sub.3BO.sub.3 at a molar ratio of 1:1, wherein the flux NaF:H.sub.3BO.sub.3 included NaF and H.sub.3BO.sub.3 at a molar ratio of 1:1. The mixture was placed into the quartz tube, which was vacuumized to a vacuum degree of 1×10.sup.−3 Pa, and subjected to vacuum packaging with a flamer.

(32) Then, the quartz tube was placed into a muffle furnace, heated at a rate of 30° C./h to 450° C. for 24 h, then cooled at a rate of 1.5° C./day to 400° C., and then cooled at a rate of 2° C./h to 25° C. The quartz tube was cut to give an SrB.sub.5O.sub.7F.sub.3 crystal with a dimension of Φ10 mm×7 mm×6 mm.

Example 8

(33) Growth of SrB.sub.5O.sub.7F.sub.3 crystal by a flux method:

(34) The SrB.sub.5O.sub.7F.sub.3 compound was synthesized according to the equation of 3Sr(BF.sub.4).sub.2+14H.sub.3BO.sub.3.fwdarw.3SrB.sub.5O.sub.7F.sub.3+5BF.sub.3↑+21H.sub.2O↑. The particular operation steps are similar to those in EXAMPLE 2.

(35) The resultant compound SrB.sub.5O.sub.7F.sub.3 was added into a quartz tube of Φ10 mm. The quartz tube was vacuumized to a vacuum degree of 1×10.sup.−3 Pa, and subjected to vacuum packaging with a flamer. The quartz tube was placed in to a muffle furnace, heated at a rate of 40° C./h to 500° C. for 40 h, then cooled at a rate of 4° C./h to 25° C., and the quartz tube was opened to give a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal.

(36) The resultant SrB.sub.5O.sub.7F.sub.3 seed crystal was placed on the bottom of the container, then the resultant compound SrB.sub.5O.sub.7F.sub.3 was mixed with a flux which is NaF:B.sub.2O.sub.3 at a molar ratio of 1:3, wherein the NaF—B.sub.2O.sub.3 system included NaF and B.sub.2O.sub.3 at a molar ratio of 1:2. The mixture was placed into the quartz tube, the quartz tube was vacuumized to a vacuum degree of 1×10.sup.−3 Pa, and was subjected to vacuum packaging with a flamer.

(37) Then, the quartz tube was placed into a muffle furnace, heated at a rate of 40° C./h to 450° C. for 20 h, then cooled at a rate of 2° C./day to 400° C. and then cooled at a rate of 3° C./h to 25° C. The quartz tube was cut to give an SrB.sub.5O.sub.7F.sub.3 crystal with a dimension of Φ5 mm×6 mm×8 mm.

Example 9

(38) Growth of SrB.sub.5O.sub.7F.sub.3 crystal by a flux method:

(39) The SrB.sub.5O.sub.7F.sub.3 compound was synthesized according to the equation of 3Sr(BF.sub.4).sub.2+14H.sub.3BO.sub.3.fwdarw.3SrB.sub.5O.sub.7F.sub.3+5BF.sub.3↑+21H.sub.2O↑. The particular operation steps are similar to those in EXAMPLE 1.

(40) The resultant compound SrB.sub.5O.sub.7F.sub.3 was added into a quartz tube of Φ10 mm, the quartz tube was vacuumized to a vacuum degree of 1×.sup.−3 Pa, and was subjected to vacuum packaging with a flamer. The quartz tube was placed into a muffle furnace, heated at a rate of 25° C./h to 300° C. for 30 h, then cooled at a rate of 3° C./h to 25° C., and the quartz tube was opened to give a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal.

(41) First, a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal was placed on the bottom of a quartz tube of φ10 mm. Then, the SrB.sub.5O.sub.7F.sub.3 compound was mixed with a flux NaBF.sub.4 at a molar ratio of 1:5. The mixture was placed into the quartz tube, and the quartz tube was vacuumized to a vacuum degree of 1×10.sup.−3 Pa, and was subjected to vacuum packaging with a flamer.

(42) Then, the quartz tube was placed into a muffle furnace, heated at a rate of 40° C./h to 600° C. for 48 h, then cooled at a rate of 3° C./day to 550° C., and then cooled at a rate of 10° C./h to 25° C. The quartz tube was cut to give an SrB.sub.5O.sub.7F.sub.3 crystal with a dimension of Φ8 mm×7 mm×6 mm.

Example 10

(43) Growth of SrB.sub.5O.sub.7F.sub.3 crystal by a flux method:

(44) The SrB.sub.5O.sub.7F.sub.3 compound was synthesized according to the equation of 3Sr(BF.sub.4).sub.2+7B.sub.2O.sub.3.fwdarw.3SrB.sub.5O.sub.7F.sub.3+5BF.sub.3↑. The particular operation steps are similar to those in EXAMPLE 1.

(45) The resultant compound SrB.sub.5O.sub.7F.sub.3 was added into the hydrothermal reactor for sealing, the hydrothermal reactor was placed into a drying oven, heated at a rate of 25° C./h to 210° C. for 15 h, then cooled at a rate of 3° C./h to 25° C., and the hydrothermal reactor was opened to give a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal.

(46) First, a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal was placed on the bottom of a quartz tube of φ10 mm, then the compound SrB.sub.5O.sub.7F.sub.3 was mixed with a flux NaF:H.sub.3BO.sub.3 at a molar ratio of 1:5, wherein the flux NaF:H.sub.3BO.sub.3 included NaF and H.sub.3BO.sub.3 at a molar ratio of 2:3. The mixture was placed into a quartz tube, and the quartz tube was vacuumized to a vacuum degree of 1×10.sup.−3 Pa, and was subjected to vacuum packaging with a flamer.

(47) Then, the quartz tube was placed into a muffle furnace, heated at a rate of 30° C./h to 450° C. for 24 h, then cooled at a rate of 1.5° C./day to 400° C., and then cooled at a rate of 2° C./h to 25° C. The quartz tube was cut to give an SrB.sub.5O.sub.7F.sub.3 crystal with a dimension of Φ5 mm×5 mm×4 mm.

Example 11

(48) Growth of SrB.sub.5O.sub.7F.sub.3 crystal by a flux method:

(49) The SrB.sub.5O.sub.7F.sub.3 compound was synthesized according to the equation of 3Sr(BF.sub.4).sub.2+7B.sub.2O.sub.3.fwdarw.3SrB.sub.5O.sub.7F.sub.3+5BF.sub.3↑. The particular operation steps are similar to those in EXAMPLE 2.

(50) The resultant compound SrB.sub.5O.sub.7F.sub.3 was added into a quartz tube of Φ10 mm, the quartz tube was vacuumized to a vacuum degree of 1×10.sup.−3 Pa, and was subjected to vacuum packaging with a flamer. The quartz tube was placed into a muffle furnace, heated at a rate of 40° C./h to 500° C. for 46 h, then cooled at a rate of 4° C./h to 25° C., and the quartz tube was opened to give a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal.

(51) The resultant SrB.sub.5O.sub.7F.sub.3 seed crystal was placed on the bottom of a quartz tube. Then, the resultant compound SrB.sub.5O.sub.7F.sub.3 was mixed with a flux which was NaF:B.sub.2O.sub.3 at a molar ratio of 1:5, wherein NaF—B.sub.2O.sub.3 system included NaF and B.sub.2O.sub.3 at a molar ratio of 1:4. The mixture was placed into the quartz tube, and the quartz tube was vacuumized to a vacuum degree of 1×10.sup.−3 Pa, and was subjected to vacuum packaging with a flamer.

(52) Then, the quartz tube was placed into a muffle furnace, heated at a rate of 40° C./h to 400° C. for 20 h, then cooled at a rate of 2° C./day to 350° C., and then cooled at a rate of 3° C./h to 25° C. The quartz tube was cut to give an SrB.sub.5O.sub.7F.sub.3 crystal with a dimension of Φ5 mm×4 mm×7 mm.

Example 12

(53) Growth of SrB.sub.5O.sub.7F.sub.3 crystal by a flux method:

(54) The SrB.sub.5O.sub.7F.sub.3 compound was synthesized according to the equation of 3Sr(BF.sub.4).sub.2+14H.sub.3BO.sub.3.fwdarw.3SrB.sub.5O.sub.7F.sub.3+5BF.sub.3↑+21H.sub.2O↑. The particular operation steps are similar to those in EXAMPLE 1.

(55) The resultant compound SrB.sub.5O.sub.7F.sub.3 was added into the hydrothermal reactor for sealing, the hydrothermal reactor was placed into a drying oven, heated at a rate of 25° C./h to 220° C. for 30 h, then cooled at a rate of 3° C./h to 25° C., and the hydrothermal reactor was opened to give a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal;

(56) First, a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal was placed on the bottom of a quartz tube of φ10 mm. Then, the SrB.sub.5O.sub.7F.sub.3 compound was mixed with a flux H.sub.3BO.sub.3 at a molar ratio of 1:5. The mixture was placed into the quartz tube, and the quartz tube was vacuumized to a vacuum degree of 1×10.sup.−3 Pa, and was subjected to vacuum packaging with a flamer.

(57) Then, the quartz tube was placed into a muffle furnace, heated at a rate of 40° C./h to 600° C. for 48 h, then cooled at a rate of 3° C. /day to 550° C. and then cooled at a rate of 10° C./h to 25° C. The quartz tube was cut to give an SrB.sub.5O.sub.7F.sub.3 crystal with a dimension of φ5 mm×6 mm×4 mm.

Example 13

(58) Growth of SrB.sub.5O.sub.7F.sub.3 crystal by a flux method:

(59) The SrB.sub.5O.sub.7F.sub.3 compound was synthesized according to the equation of 3Sr(BF.sub.4).sub.2+14H.sub.3BO.sub.3.fwdarw.3SrB.sub.5O.sub.7F.sub.3+5BF.sub.3↑+21H.sub.2O↑. The particular operation steps are similar to those in EXAMPLE 2.

(60) The resultant compound SrB.sub.5O.sub.7F.sub.3 was added into a quartz tube of Φ10 mm, the quartz tube was vacuumized to a vacuum degree of 1×10.sup.−3 Pa, and was subjected to vacuum packaging with a flamer. The quartz tube was placed into a muffle furnace, heated at a rate of 35° C./h to 550° C. for 40 h, then cooled at a rate of 5° C./h to 25° C., and the quartz tube was opened to give a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal.

(61) The resultant SrB.sub.5O.sub.7F.sub.3 seed crystal was placed on the bottom of a quartz tube. Then, the resultant compound SrB.sub.5O.sub.7F.sub.3 was mixed with a flux which is NaF:B.sub.2O.sub.3 at a molar ratio of 1:5, wherein NaF—B.sub.2O.sub.3 system included NaF and B.sub.2O.sub.3 at a molar ratio of 2:3. The mixture was placed into the quartz tube, and the quartz tube was vacuumized to a vacuum degree of 1×10.sup.−3 Pa, and was subjected to vacuum packaging with a flamer.

(62) Then, the quartz tube was placed into a muffle furnace, heated at a rate of 35° C./h to 450° C. for 36 h, then cooled at a rate of 4° C./day to 400° C., and then cooled at a rate of 10° C./h to 30° C. The quartz tube was cut to give an SrB.sub.5O.sub.7F.sub.3 crystal with a dimension of Φ6 mm×7 mm×4 mm.

Example 14

(63) Growth of SrB.sub.5O.sub.7F.sub.3 crystal by a flux method:

(64) The SrB.sub.5O.sub.7F.sub.3 compound was synthesized according to the equation of 3Sr(BF.sub.4).sub.2+14H.sub.3BO.sub.3.fwdarw.3SrB.sub.5O.sub.7F.sub.3+5BF.sub.3↑+21H.sub.2O↑. The particular operation steps are similar to those in EXAMPLE 1.

(65) The resultant compound SrB.sub.5O.sub.7F.sub.3 was added into a quartz tube of Φ10 mm, the quartz tube was vacuumized to a vacuum degree of 1×10.sup.−3 Pa, and was subjected to vacuum packaging with a flamer. The quartz tube was placed into a muffle furnace, heated at a rate of 40° C./h to 550° C. for 25 h, then cooled at a rate of 4° C./h to 25° C. The quartz tube was cut to give a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal.

(66) First, a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal was placed on the bottom of a quartz tube of φ10 mm, then the compound SrB.sub.5O.sub.7F.sub.3 was mixed with a flux NaF:H.sub.3BO.sub.3 at a molar ratio of 1:10, wherein the flux NaF:H.sub.3BO.sub.3 included NaF and H.sub.3BO.sub.3 at a molar ratio of 3:5. The mixture was placed into a quartz tube, and the quartz tube was vacuumized to a vacuum degree of 1×10.sup.−3 Pa, and was subjected to vacuum packaging with a flamer.

(67) Then, the quartz tube was placed into a muffle furnace, heated at a rate of 40° C./h to 550° C. for 40 h, then cooled at a rate of 3° C./day to 500° C., and then cooled at a rate of 8° C./h to 25° C. The quartz tube was cut to give an SrB.sub.5O.sub.7F.sub.3 crystal with a dimension of Φ9 mm×7 mm×6 mm.

Example 15

(68) Growth of SrB.sub.5O.sub.7F.sub.3 crystal by a flux method:

(69) The SrB.sub.5O.sub.7F.sub.3 compound was synthesized according to the equation of 3Sr(BF.sub.4).sub.2+14H.sub.3BO.sub.3.fwdarw.3SrB.sub.5O.sub.7F.sub.3+5BF.sub.3↑+21H.sub.2O↑. The particular operation steps are similar to those in EXAMPLE 1.

(70) The resultant compound SrB.sub.5O.sub.7F.sub.3 was added into a quartz tube of Φ10 mm, the quartz tube was vacuumized to a vacuum degree of 1×10.sup.−3 Pa, and was subjected to vacuum packaging with a flamer. The quartz tube was placed into a muffle furnace, heated at a rate of 30° C./h to 500° C. for 15 h, then cooled at a rate of 5° C./h to 25° C., and the hydrothermal reactor or the quartz tube was opened to give a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal.

(71) First, a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal was placed on the bottom of a quartz tube of φ10 mm. Then, the SrB.sub.5O.sub.7F.sub.3 compound was mixed with a flux B.sub.2O.sub.3 at a molar ratio of 1:10. The mixture was placed into the quartz tube, and the quartz tube was vacuumized to a vacuum degree of 1×10.sup.−3 Pa, and was subjected to vacuum packaging with a flamer.

(72) Then, the quartz tube was placed into a muffle furnace, heated at a rate of 40° C./h to 500° C. for 45 h, then cooled at a rate of 3° C. /day to 450° C., and then cooled at a rate of 6° C./h to 25° C. The quartz tube was cut to give an SrB.sub.5O.sub.7F.sub.3 crystal with a dimension of Φ7 mm×6 mm×4 mm.

(73) Example 16

(74) Growth of SrB.sub.5O.sub.7F.sub.3 crystal by a Bridgman-Stockbarger method:

(75) The SrB.sub.5O.sub.7F.sub.3 compound was synthesized according to the equation of 3Sr(BF.sub.4).sub.2+7B.sub.2O.sub.3.fwdarw.3SrB.sub.5O.sub.7F.sub.3+5BF.sub.3↑. The particular operation steps are similar to those in EXAMPLE 1.

(76) The resultant compound SrB.sub.5O.sub.7F.sub.3 was added into a quartz tube of Φ10 mm, the quartz tube was vacuumized to a vacuum degree of 1×10.sup.−3 Pa, and was subjected to vacuum packaging with a flamer. The quartz tube was placed in to a muffle furnace, heated at a rate of 40° C./h to 600° C. for 60 h, then cooled at a rate of 5° C./h to 25° C., and the hydrothermal reactor or the quartz tube was opened to give a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal.

(77) The resultant seed crystal was placed on the bottom of a platinum crucible, and then the resultant compound SrB.sub.5O.sub.7F.sub.3 was added into the platinum crucible. The platinum crucible was sealed and placed in a crucible descending furnace, heated to 300° C. for 10 h. The position of the container was adjusted to achieve the spontaneous nucleation temperature, and the container was slowly descended at a rate of 0.05 mm/h while the growing temperature was kept constant. After the completion of growth, the growth furnace was cooled to 25° C., and removed to give a crystal with a dimension of Φ6 mm×5 mm×4 mm.

Example 17

(78) Growth of SrB.sub.5O.sub.7F.sub.3 crystal by a Bridgman-Stockbarger method:

(79) The SrB.sub.5O.sub.7F.sub.3 compound was synthesized according to the equation of 3Sr(BF.sub.4).sub.2+7B.sub.2O.sub.3.fwdarw.3SrB.sub.5O.sub.7F.sub.3+5BF.sub.3↑. The particular operation steps are similar to those in EXAMPLE 1.

(80) The resultant compound SrB.sub.5O.sub.7F.sub.3 was added into the hydrothermal reactor for sealing, the hydrothermal reactor was placed into a drying oven, heated at a rate of 20° C./h to 200° C. for 10 h, then cooled at a rate of 1° C./h to 25° C., and the hydrothermal reactor was opened to give a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal.

(81) The resultant seed crystal was placed on the bottom of an iridium crucible, and then the resultant compound SrB.sub.5O.sub.7F.sub.3 was added into the iridium crucible.

(82) The iridium crucible was sealed and placed into a crucible descending furnace, and heated to 650° C. for 20 h. The position of the iridium crucible was adjusted, so that the seeding temperature was 350° C., and then the container was slowly descended at a rate of 2 mm/h and was cooled slowly at a rate of 3° C./h. After the completion of growth, the growth furnace was cooled to 25° C. The iridium crucible was removed to give an SrB5O.sub.7F.sub.3 crystal with a dimension of Φ7 mm×6 mm×5 mm.

(83) Example 18

(84) Growth of SrB.sub.5O.sub.7F.sub.3 crystal by a Bridgman-Stockbarger method:

(85) The SrB.sub.5O.sub.7F.sub.3 compound was synthesized according to the equation of 3Sr(BF.sub.4).sub.2+7B.sub.2O.sub.3.fwdarw.3SrB.sub.5O.sub.7F.sub.3+5BF.sub.3↑. The particular operation steps are similar to those in EXAMPLE 1.

(86) The resultant compound SrB.sub.5O.sub.7F.sub.3 was added into a quartz tube of Φ10 mm, the quartz tube was vacuumized to a vacuum degree of 1×10.sup.−3 Pa, and was subjected to vacuum packaging with a flamer. The quartz tube was placed into a muffle furnace, heated at a rate of 30° C./h to 400° C. for 36 h, then cooled at a rate of 3° C./h to 25° C. The quartz tube was cut to give a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal.

(87) The resultant seed crystal was placed on the bottom of a ceramic crucible, and then the resultant compound SrB.sub.5O.sub.7F.sub.3 was added into the ceramic crucible. The ceramic crucible was sealed and placed in a crucible descending furnace, and heated to 450° C. for 15 h. The position of the ceramic crucible was adjusted, so that the seeding temperature was 400° C., and then the ceramic crucible was slowly descended at a rate of 0.5 mm/h while the growing temperature was kept constant. After the completion of growth, the growth furnace was cooed to 25° C. The ceramic crucible was removed to give a crystal with a dimension of Φ6 mm×8 mm×12mm.

Example 19

(88) Growth of SrB.sub.5O.sub.7F.sub.3 crystal by a Bridgman-Stockbarger method:

(89) The SrB.sub.5O.sub.7F.sub.3 compound was synthesized according to the equation of 3Sr(BF.sub.4).sub.2+7B.sub.2O.sub.3.fwdarw.3SrB.sub.5O.sub.7F.sub.3+5BF.sub.3↑. The particular operation steps are similar to those in EXAMPLE 1.

(90) The resultant compound SrB.sub.5O.sub.7F.sub.3 was added into a hydrothermal reactor for sealing, the hydrothermal reactor was placed into a drying oven, heated at a rate of 20° C./h to 200° C. for 10 h, then cooled at a rate of 1° C./h to 25° C., and the hydrothermal reactor was opened to give a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal.

(91) The resultant seed crystal was placed on the bottom of a quartz tube, and then the resultant compound SrB.sub.5O.sub.7F.sub.3 was placed into a quartz tube.

(92) The quartz tube was vacuumized to a vacuum degree of 1×10.sup.−3 Pa, and was subjected to vacuum packaging with a flamer. The quartz tube was placed into a crucible descending furnace, and heated to 600° C. for 20 h. The position of the quartz tube was adjusted, so that the seeding temperature was 600° C., and then the quartz tube was slowly descended at a rate of 1 mm/h and was cooled slowly at a rate of 2° C./h. After the completion of growth, the growth furnace was cooled to 25° C. The quartz tube was removed to give an SrB.sub.5O.sub.7F.sub.3 crystal with a dimension of Φ7 mm×6 mm×5 mm.

(93) Example 20

(94) Growth of SrB.sub.5O.sub.7F.sub.3 crystal by a solvothermal method:

(95) The SrB.sub.5O.sub.7F.sub.3 compound was synthesized according to the equation of 3Sr(BF.sub.4).sub.2+7B.sub.2O.sub.3.fwdarw.3SrB.sub.5O.sub.7F.sub.3+5BF.sub.3↑. The particular operation steps are similar to those in EXAMPLE 2.

(96) The resultant compound SrB.sub.5O.sub.7F.sub.3 was added into a hydrothermal reactor for sealing. The hydrothermal reactor was placed into a drying oven, heated at a rate of 20° C./h to 150° C. for 10 h, then cooled at a rate of 1° C./h to 25° C., and the hydrothermal reactor was opened to give a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal.

(97) The resultant seed crystal was placed on the bottom of the PTFE lining of a clean and non-contaminated hydrothermal reactor with a volume of 23 mL. Then, the resultant compound SrB.sub.5O.sub.7F.sub.3 was added into the PTFE lining.

(98) A solvent which was deionized water was added into the PTFE lining. The hydrothermal reactor was tightly sealed and placed into a drying oven, heated at a rate of 20° C./h to 150° C. for 24 h, then cooled at a rate of 2° C./day to 130° C., and then cooled at a rate of 2° C./h to 25° C., and the hydrothermal reactor was opened to give an SrB.sub.5O.sub.7F.sub.3 crystal with a dimension of Φ5 mm×6 mm×8 mm.

Example 21

(99) Growth of SrB.sub.5O.sub.7F.sub.3 crystal by a solvothermal method:

(100) The SrB.sub.5O.sub.7F.sub.3 compound was synthesized according to the equation of 3Sr(BF.sub.4).sub.2+14H.sub.3BO.sub.3.fwdarw.3SrB.sub.5O.sub.7F.sub.3+5BF.sub.3↑+21H.sub.2O↑. The particular operation steps are similar to those in EXAMPLE 2.

(101) The resultant compound SrB.sub.5O.sub.7F.sub.3 was placed on the bottom of the PTFE lining of a clean and non-contaminated hydrothermal reactor with a volume of 23 mL. The hydrothermal reactor was placed into a drying oven, heated at a rate of 20° C./h to 230° C. for 10 h, then cooled at a rate of 1° C./h to 25° C., and the hydrothermal reactor was opened to give a seed crystal of S SrB.sub.5O.sub.7F.sub.3 crystal.

(102) The resultant seed crystal was placed on the bottom of the PTFE lining of the hydrothermal reactor, and then the resultant compound SrB.sub.5O.sub.7F.sub.3 was added into the PTFE lining of the hydrothermal reactor.

(103) To the PTFE lining of the hydrothermal reactor was added 10 mL of solvent which was hydrofluoric acid. The hydrothermal reactor was tightly sealed and placed into a drying oven, heated at a rate of 20° C./h to 200° C. for 24 h, then cooled at a rate of 2° C./day to 100° C., and then cooled at a rate of 2° C./h to 25° C., and the hydrothermal reactor was opened to give an SrB.sub.5O.sub.7F.sub.3 crystal with a dimension of Φ5 mm×6 mm×4 mm.

Example 22

(104) Growth of SrB.sub.5O.sub.7F.sub.3 crystal by a solvothermal method:

(105) The SrB.sub.5O.sub.7F.sub.3 compound was synthesized according to the equation of 3Sr(BF.sub.4).sub.2+14H.sub.3BO.sub.3.fwdarw.3SrB.sub.5O.sub.7F.sub.3+5BF.sub.3↑+21H.sub.2O↑. The particular operation steps are similar to those in EXAMPLE 2.

(106) The resultant compound SrB.sub.5O.sub.7F.sub.3 was placed on the bottom of a clean and non-contaminated hydrothermal reactor equipped with a platinum sleeving and a stainless steel lining and having a volume of 50 mL. The hydrothermal reactor was placed in to a muffle furnace, heated at a rate of 30° C./h to 300° C. for 15 h, then cooled at a rate of 2° C./h to 25° C., and the hydrothermal reactor was opened to give a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal.

(107) The resultant seed crystal was placed on the bottom of a hydrothermal reactor equipped with a platinum sleeving and a stainless steel lining, and then the resultant compound SrB.sub.5O.sub.7F.sub.3 was added into the hydrothermal reactor equipped with a platinum sleeving and a stainless steel lining.

(108) To the hydrothermal reactor equipped with a platinum sleeving and a stainless steel lining platinum was added 50 mL of solvent which was deionized water. The hydrothermal reactor was tightly sealed and placed into a muffle furnace, heated at a rate of 30° C./h to 250° C. for 24 h, and then cooled at a rate of 2° C./day to 200° C., and then cooled at a rate of 5° C./h to 25° C., and the hydrothermal reactor was opened to give an SrB.sub.5O.sub.7F.sub.3 crystal with a dimension of Φ5 mm×4 mm×3 mm.

Example 23

(109) Growth of SrB.sub.5O.sub.7F.sub.3 crystal by a solvothermal method:

(110) The SrB.sub.5O.sub.7F.sub.3 compound was synthesized according to the equation of 3Sr(BF.sub.4).sub.2+14H.sub.3BO.sub.3.fwdarw.3SrB.sub.5O.sub.7F.sub.3+5BF.sub.3↑+21H.sub.2O↑. The particular operation steps are similar to those in EXAMPLE 2.

(111) The resultant compound SrB.sub.5O.sub.7F.sub.3 was placed on the bottom of a clean and non-contaminated hydrothermal reactor equipped with a platinum sleeving and a stainless steel lining and having a volume of 23 mL. The hydrothermal reactor was placed into a muffle furnace, heated at a rate of 35° C./h to 500° C. for 48 h, then cooled at a rate of 4° C./h to 25° C., and the hydrothermal reactor was opened to give a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal.

(112) The resultant seed crystal was placed on the bottom of a hydrothermal reactor equipped with a platinum sleeving and a stainless steel lining, and then the resultant compound SrB.sub.5O.sub.7F.sub.3 was added into the hydrothermal reactor equipped with a platinum sleeving and a stainless steel lining.

(113) To the hydrothermal reactor equipped with a platinum sleeving and a stainless steel lining was added 80 mL of solvent which was hydrofluoric acid. The hydrothermal reactor was tightly sealed, placed in a muffle furnace, heated at a rate of 40° C./h to 600° C. for 48 h, and then cooled at a rate of 3° C./day to 550° C., and then cooled at a rate of 10° C./h to 25° C., and the hydrothermal reactor was opened to give an SrB.sub.5O.sub.7F.sub.3 crystal with a dimension of Φ5 mm×6 mm×8 mm.

Example 24

(114) Growth of SrB.sub.5O.sub.7F.sub.3 crystal by a solvothermal method:

(115) The SrB.sub.5O.sub.7F.sub.3 compound was synthesized according to the equation of 3Sr(BF.sub.4).sub.2+14H.sub.3BO.sub.3.fwdarw.3SrB.sub.5O.sub.7F.sub.3+5BF.sub.3↑+21H.sub.2O↑. The particular operation steps are similar to those in EXAMPLE 2.

(116) The resultant compound SrB.sub.5O.sub.7F.sub.3 was placed on the bottom of the PTFE lining of a clean and non-contaminated hydrothermal reactor with a volume of 23 mL. The hydrothermal reactor was placed into a resistance furnace, heated at a rate of 40° C./h to 220° C. for 48 h, then cooled at a rate of 5° C./h to 25° C., and the hydrothermal reactor was opened to give a seed crystal of SrB.sub.5O.sub.7F.sub.3 crystal.

(117) The resultant seed crystal was placed on the bottom the PTFE lining of the hydrothermal reactor, and then the resultant compound SrB.sub.5O.sub.7F.sub.3 was added into the PTFE lining of the hydrothermal reactor.

(118) To the PTFE lining of the hydrothermal reactor was added 10 mL of solvent which was deionized water. The hydrothermal reactor was tightly sealed, placed into a drying oven, heated at a rate of 40° C./h to 210° C. for 35 h, and then cooled at a rate of 3° C./day to 160° C. and then cooled at a rate of 4° C./h to 25° C., and the hydrothermal reactor was opened to give an SrB.sub.5O.sub.7F.sub.3 crystal with a dimension of Φ5 mm×6 mm×3 mm.

Example 25

(119) Any of SrB.sub.5O.sub.7F.sub.3 crystals obtained in Examples 1-24 was processed in the phase-matching direction, and positioned at the site 3 as shown in FIG. 2. At room temperature, a Q-switched Nd:YAG laser was used as a light source with an incident wavelength of 1064 nm. The Q-switched Nd:YAG laser 1 emitted an infrared light beam 2 with a wavelength of 1064 nm into the SrB.sub.5O.sub.7F.sub.3 single crystal 3, thereby producing a green harmonic light with a wavelength of 532 nm with an output intensity which was 1.5 times of KDP on equal conditions.

(120) Example 26

(121) Any of SrB.sub.5O.sub.7F.sub.3 crystals obtained in Examples 1-24 was processed in the phase-matching direction, and positioned at the site 3 as shown in FIG. 2. At room temperature, a Q-switched Nd:YAG laser was used as a light source with an incident wavelength of 532 nm. The Q-switched Nd:YAG laser 1 emitted an infrared light beam 2 with a wavelength of 532 nm into the SrB.sub.5O.sub.7F.sub.3 single crystal 3, thereby producing a harmonic light with a wavelength of 266 nm with an output intensity which was about 0.3 time of BBO on equal conditions.

(122) Example 27

(123) Any of SrB.sub.5O.sub.7F.sub.3 crystals obtained in Examples 1-24 was processed in the phase-matching direction, and positioned at the site 3 as shown in FIG. 2. At room temperature, a Q-switched Nd:YAG laser was used as a light source with an incident wavelength of 355 nm. The Q-switched Nd:YAG laser 1 emitted an infrared light beam 2 with a wavelength of 355 nm into the SrB.sub.5O.sub.7F.sub.3 single crystal 3, and the output of a deep UV harmonic light with a wavelength of 177.3 nm was observed.

(124) Of course, the present invention can further have various embodiments. Without departing from the spirit and essence of the present invention, those of ordinary skill in the art can make various corresponding changes and modifications according to the disclosure of the present invention. However, these corresponding changes and modifications should all fall within the protection scope of the claims in the present invention.