Compound chloroiodorubidium and chloroiodoammonium and chloroiodorubidium and chloroiodoammonium birefringent optical crystals and methods of preparation and use

Abstract

This invention relates to the compounds rubidium chloroiodide and ammonium chloroiodide, as well as birefringent optical crystals of rubidium chloroiodide and ammonium chloroiodide, their preparation methods, and applications. The chemical formulas of the compounds are RbICl2 and NH4ICl2, with molecular weights of 283.27 and 215.84, respectively. The chemical formulas of the crystals are RbICl2 and NH4ICl2, with molecular weights of 283.27 and 215.84, respectively. They crystallize in an orthorhombic crystal system with space group [missing information]. Pnma The cell parameters of RbICl2 are: a =10.1376(18)Å, b =6.2403(15)Å, c =8.4701(18)Å, α = β = gamma =90°, V=535.83(20)Å 3 The cell parameters of NH4ICl2 are: a =10.145(7), b =6.155(4)Å, c =8.451(4)Å, α = β = gamma =90°, V=527.70(56)Å 3 The prepared rubidium chloroiodide crystal exhibits a laser damage threshold 8 times that of AgGaS2 and a birefringence 3.7 times that of YVO4, with a value of 0.75 at 546 nm. The ammonium chloroiodide crystal shows a birefringence 3.4 times that of YVO4, with a value of 0.70 at 546 nm. These crystals possess moderate mechanical hardness, are easy to cut, polish, and store, and exhibit high birefringence, making them valuable for applications in optics and communications.

Description

Technical Field

[0001] This invention belongs to the field of birefringent optical crystal materials, and relates to a compound rubidium chloride and ammonium chloride, a birefringent optical crystal of rubidium chloride and ammonium chloride, its preparation method and application. Background Technology

[0002] Birefringent crystal materials are key functional components for achieving polarization control and phase matching in all-solid-state laser systems, and have a decisive impact on the performance of applications such as laser frequency conversion, optical isolation, and sensing. Their birefringence properties directly affect the output efficiency and stability of the laser system; therefore, the exploration and performance optimization of high-birefringent crystal materials has always been an important research direction in the field of laser optics. Currently, oxides and halides are commonly used birefringent materials in the ultraviolet and visible light bands, such as YVO4 (0.204@546 nm), TiO2 (0.256@546 nm), and CaCO3 (0.174@533 nm). α BaB₂O₄ (0.122@546 nm), LiNbO₃ (0.084@633 nm), and MgF₂ (0.012@546 nm) have been commercially applied. However, the birefringence of these materials is generally below 0.3, which to some extent limits their application in compact, high-efficiency optical devices. The core performance indicators of birefringent crystals mainly include high birefringence and suitable transmission band, which depend on the polarization anisotropy of the birefringent active building blocks and the characteristics of their constituent atoms, respectively. By introducing linear structural building blocks with significant optical anisotropy into the crystal structure, the birefringence of the material can be effectively improved. For example, [I₃] ⁻ The birefringence of the linear unit C3H8N6I6·3H2O can reach 2.8; the birefringence of Hg4InS2Cl5 containing the [Hg2S2] unit is 0.35 at 546 nm; the birefringence of RbHg5Br containing the [HgBr2] unit is... 11 The birefringence is also 0.35 at the same wavelength. Among these linear building blocks, especially those containing heavy atoms (X = O, Cl, Br, I, etc.), the chemical bond vibration frequencies are low, which helps extend the infrared transmission range of the material to the mid-infrared and even far-infrared regions. Therefore, for infrared optical applications, there is an urgent need to develop novel birefringent materials with large birefringence, wide transmission range, and good crystal growth habits to meet the ever-increasing performance requirements of advanced laser technology in polarization control and frequency conversion. The rubidium chloroiodide and ammonium chloroiodide infrared birefringent crystals provided in this invention have moderate mechanical hardness, are easy to cut, polish, and store, and have the advantages of large birefringence. Summary of the Invention

[0003] The purpose of this invention is to provide compounds rubidium chloride and ammonium chloride, with the chemical formulas RbICl2 and NH4ICl2, respectively, and molecular weights of 283.27 and 215.84, respectively.

[0004] Another objective of this invention is to provide infrared birefringent optical crystals of rubidium chloride-iodide and ammonium chloride-iodide, with chemical formulas RbICl2 and NH4ICl2, molecular weights of 283.27 and 215.84, respectively, belonging to the orthorhombic crystal system and space group [missing information]. Pnma, The cell parameters of RbICl2 are a = 10.1376(18) Å, b = 6.2403(15) Å, c = 8.4701(18) Å, α = β = γ = 90°, V = 535.83(20) Å 3 The cell parameters of NH4ICl2 are: a = 10.145(7) Å, b = 6.155(4) Å, c = 8.451(4) Å, α = β = γ = 90°, V = 527.70(56) Å 3 .

[0005] Another objective of this invention is to provide a method for preparing infrared birefringent optical crystals of rubidium chloride and ammonium chloride.

[0006] Another object of the present invention is to provide the use of rubidium chloride and ammonium chloride infrared birefringent optical crystals.

[0007] The present invention discloses two compounds, rubidium chloride-iodide and ammonium chloride-iodide, with chemical formulas RbICl2 and NH4ICl2, and molecular weights of 283.27 and 215.84, respectively. Both compounds crystallize in an orthorhombic crystal system with space group [missing information]. Pnma, The cell parameters of RbICl2 are a = 10.1376(18) Å, b = 6.2403(15) Å, c = 8.4701(18) Å, α = β = γ =90°, V = 535.83(20) Å 3 The cell parameters of NH4ICl2 are: a = 10.145(7),b = 6.155(4) Å, c =8.451(4) Å, α = β = γ = 90°, V = 527.70(56) Å 3 Both are yellow crystals with centrosymmetric structures. The structure of rubidium chloride-iodide consists of linear [ICl2] units and [RbCl8] polyhedra; the structure of ammonium chloride-iodide consists of linear [ICl2] units and [NH4] tetrahedra.

[0008] A rubidium chloride-iodide and ammonium chloride-iodide infrared birefringent optical crystal, with the chemical formulas RbICl2 and NH4ICl2 respectively, and molecular weights of 283.27 and 215.84 respectively, both crystallize in an orthorhombic crystal system with space group [missing information]. Pnma, The cell parameters of RbICl2 are a = 10.1376(18) Å, b = 6.2403(15) Å, c = 8.4701(18) Å, α = β = γ =90°, V = 535.83(20) Å 3 The cell parameters of NH4ICl2 are: a = 10.145(7), b = 6.155(4) Å, c =8.451(4) Å, α = β = γ = 90°, V = 527.70(56) Å 3 .

[0009] The method for preparing the chloroiodine-rubidium and chloroiodine-ammonium birefringent optical crystals involves using a hydrothermal method or a room-temperature solvent method. The hydrothermal method was used to prepare rubidium chloride-iodide and ammonium chloride-iodide birefringent optical crystals. The specific operation was carried out according to the following steps: a. Accurately weigh the Rb source / NH3 source, I source, and Cl source. Measure HCl and H2O in a molar ratio of HCl:H2O = 1:5. Place the weighed raw materials into a beaker and stir to dissolve. After complete dissolution, transfer the solution to a 50 ml polytetrafluoroethylene (PTFE) liner. Then, place the PTFE liner in a high-pressure reactor and seal it. The Rb source material is Rb2CO3, RbI, or RbCl; the I source material is I2O5 or HIO3; the Cl source material is ICl or 12 mol / L hydrochloric acid solution; and the NH3 source material is NH4HCO3, (NH4)2CO3, or NH4Cl. b. Place the sealed high-pressure reactor from step a into an oven and heat it to 150-210 ℃ at a heating rate of 1-5 ℃ / min. Hold it at this temperature for 48-72 h. Then, cool it down to room temperature at a cooling rate of 0.1-0.5 ℃ / min. The crystal will spontaneously crystallize during the cooling process, thus obtaining rubidium chloride-iodide and ammonium chloride-iodide birefringent optical crystals. The room-temperature solvent method for growing rubidium chloroiodide and ammonium chloroiodide birefringent optical crystals is carried out according to the following steps: a. Accurately weigh the Rb source / NH3 source, I source, and Cl source, mix them thoroughly and grind them evenly. Measure HCl and H2O in a molar ratio of HCl:H2O = 1:3-7. Place the weighed raw materials into a clean glass beaker and stir at room temperature until completely dissolved to obtain a mixed solution. The Rb source material is Rb2CO3, RbI, or RbCl; the I source material is I2O5 or HIO3; the Cl source material is ICl or 12mol / L hydrochloric acid solution; and the NH3 source material is NH4HCO3, (NH4)2CO3, or NH4Cl. b. Let the mixed solution from step a stand, filter to remove insoluble matter, transfer the clear filtrate to a wide-mouth crystallizing dish, cover the container mouth with a membrane or filter paper with micropores, and allow the solvent to slowly evaporate naturally at room temperature and in a vibration-free environment. c. After the solution in step b evaporates to the point of supersaturation, the crystal will gradually precipitate and grow over two to three weeks, yielding rubidium chloride and ammonium chloride birefringent optical crystals.

[0010] 5. The use of the rubidium chloride-iodide and ammonium chloride-iodide birefringent optical crystals as described in claim 3 in the fabrication of polarizing beam splitters such as Glan prisms, Wollaston prisms, and Lochon prisms, as well as optical devices such as optical isolators, circulators, and beam shifters.

[0011] The compounds rubidium chloride and ammonium chloride described in this invention are prepared according to the following chemical reaction formula: Rb2CO3 + I2O5 + 12HCl = 2RbICl2 + 4Cl2 + CO2 + 6H2O; 2RbCl + I2O5 + 10HCl = 2RbICl2 + 4Cl2 + 5H2O; Rb2CO3 + 2HIO3 + 12HCl = 2RbICl2 + 4Cl2 + CO2 + 7H2O 2NH4HCO3 + I2O5 + 12HCl = 2 NH4ICl2 + 4Cl2 + 2CO2 + 7H2O 2NH4Cl + I2O5 + 10HCl = 2 NH4ICl2 + 4Cl2 + 5H2O (NH4)2CO3 + 2HIO3 + 12HCl = 2 NH4ICl2 + 4Cl2 + CO2 + 7H2O.

[0012] This invention relates to the compounds rubidium chloride-iodide and ammonium chloride-iodide, as well as birefringent optical crystals of rubidium chloride-iodide and ammonium chloride-iodide, their preparation methods, and applications. The chemical formulas of the compounds are RbICl2 and NH4ICl2, with molecular weights of 283.27 and 215.84, respectively. The chemical formulas of the crystals are RbICl2 and NH4ICl2, with molecular weights of 283.27 and 215.84, respectively. They crystallize in an orthorhombic crystal system with space group [missing information]. Pnma The cell parameters of RbICl2 are: a = 10.1376(18) Å, b = 6.2403(15) Å, c = 8.4701(18) Å, α = β = γ = 90°, V = 535.83(20) Å 3 The cell parameters of NH4ICl2 are: a = 10.145(7), b =6.155(4) Å, c = 8.451(4) Å, α = β = γ = 90°, V = 527.70(56) Å 3The prepared rubidium chloroiodide crystal has a laser damage threshold 8 times that of AgGaS2, a birefringence 3.7 times that of YVO4, and a value of 0.75 at 546 nm; the ammonium chloroiodide crystal has a birefringence 3.4 times that of YVO4, and a value of 0.70 at 546 nm. Both the rubidium chloroiodide and ammonium chloroiodide birefringent crystals possess moderate mechanical hardness, are easy to cut, polish, and store, and exhibit high birefringence. They are suitable for fabricating polarizing beam splitters such as Glan prisms, Wollaston prisms, and Lochtein prisms, as well as optical devices such as optical isolators, circulators, and beam shifters, and have significant application value in the fields of optics and communications.

[0013] The rubidium chloride-iodide and ammonium chloride-iodide infrared birefringent optical crystals described in this invention can be used in the infrared band. Figure 3 Both are biaxial crystals. The laser damage threshold of rubidium chloride-iodide crystal is 8 times that of AgGaS2, and its birefringence is 3.7 times that of YVO4, with a value of 0.75 at 546 nm. Figure 4 The birefringence of ammonium chloride crystal is 3.4 times that of YVO4, and is 0.70 at 546 nm. Figure 5 ). Attached Figure Description

[0014] Figure 1 The crystal structure diagram of RbICl2 is shown below. Figure 2 The crystal structure diagram of NH4ICl2 is shown below. Figure 3 The transmission spectrum of RbICl2; Figure 4 This is the theoretical birefringence diagram of RbICl2; Figure 5 The theoretical birefringence diagram of NH4ICl2; Figure 6 A schematic diagram of a Glan prism for infrared band fabricated from the crystal obtained in this invention; Figure 7 A schematic diagram of a Wollaston prism for the infrared band fabricated from the crystal obtained in this invention; Figure 8 This is a schematic diagram of the wedge-shaped birefringent crystal polarization beam splitter for the infrared band of the present invention, where 1 is the incident light, 2 is the o-ray, 3 is the e-ray, 4 is the optical axis, and 5 is the crystal. Figure 9 This is a schematic diagram of an infrared optical isolator made from the crystal obtained in this invention. In the diagram, Figure a shows the transmission process of a forward incident light beam, Figure b shows the process of the reflected light being blocked, and 6 represents the light transmission direction. Detailed Implementation

[0015] Any feature disclosed in this invention, unless specifically stated otherwise, may be replaced by other equivalent or similar features. Unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features. The descriptions are merely illustrative and should not be construed as limiting the invention.

[0016] The present invention will now be described in detail through the following embodiments. Example 1

[0017] The compound rubidium chloride-iodide was prepared by a hydrothermal method based on the chemical reaction Rb₂CO₃ + I₂O₅ + 12HCl = 2RbICl₂ + 4Cl₂ + CO₂ + 6H₂O. The specific operation is as follows: a. Accurately weigh 0.409 g Rb2CO3 and 0.591 g I2O5, and measure 2 ml HCl and 6 ml H2O in a molar ratio of HCl:H2O=1:3; place the weighed raw materials into a beaker and stir to dissolve. After complete dissolution, transfer the solution to a 25 ml polytetrafluoroethylene (PTFE) liner, and then place the PTFE liner into a high-pressure reactor and seal it. b. Place the sealed high-pressure reactor from step a into an oven and heat it to 150 ℃ at a rate of 1 ℃ / min. Maintain the temperature for 72 h. After washing with deionized water and drying at room temperature, grind the mixture to obtain the compound rubidium chloride. Example 2

[0018] The compound rubidium chloride-iodide was prepared by a hydrothermal method based on the chemical reaction 2RbCl + I₂O₅ + 10HCl = 2RbICl₂ + 4Cl₂ + 5H₂O. The specific operation was carried out according to the following steps: a. Accurately weigh 0.420 g RbCl and 0.580 g I2O5, and measure 2 ml HCl and 10 ml H2O in a molar ratio of HCl:H2O=1:5. Place the weighed raw materials into a beaker and stir to dissolve. After complete dissolution, transfer the solution to a 25 ml polytetrafluoroethylene (PTFE) liner, and then place the PTFE liner into a high-pressure reactor and seal it. b. Place the high-pressure reactor from step a into an oven and heat it to 180 ℃ at a rate of 3 ℃ / min. Hold the temperature for 60 h. After washing with deionized water and drying at room temperature, grind the mixture to obtain the compound rubidium chloride. Example 3

[0019] The compound rubidium chloride-iodide was prepared by a hydrothermal method based on the chemical reaction Rb₂CO₃ + 2HIO₃ + 12HCl = 2RbICl₂ + 4Cl₂ + CO₂ + 7H₂O. The specific operation was carried out according to the following steps: a. Accurately weigh 0.396 g Rb2CO3 and 0.604 g HIO3, and measure 2 ml HCl and 14 ml H2O in a molar ratio of HCl:H2O=1:7; place the weighed raw materials into a beaker and stir to dissolve. After complete dissolution, transfer the solution to a 25 ml polytetrafluoroethylene (PTFE) liner, and then place the PTFE liner in a high-pressure reactor and seal it. b. Place the sealed high-pressure reactor from step a into an oven and heat it to 210 ℃ at a rate of 5 ℃ / min. Maintain the temperature for 48 h. After washing with deionized water and drying at room temperature, grind the mixture to obtain the compound rubidium chloride iodide. Example 4

[0020] The compound ammonium chloride was prepared by a hydrothermal method based on the chemical reaction 2NH4HCO3 + I2O5 + 12HCl = 2NH4ICl2 + 4Cl2 + 2CO2 + 7H2O. The specific operation is as follows: a. Accurately weigh 0.191 g NH4HCO3 and 0.809 g I2O5, and measure 2 ml HCl and 6 ml H2O in a molar ratio of HCl:H2O=1:3; place the weighed raw materials into a beaker and stir to dissolve. After complete dissolution, transfer the solution to a 25 ml polytetrafluoroethylene (PTFE) liner, and then place the PTFE liner in a high-pressure reactor and seal it. b. Place the sealed high-pressure reactor from step a into an oven and heat it to 150 ℃ at a rate of 1 ℃ / min. Maintain the temperature for 72 h. After washing with deionized water and drying at room temperature, grind the mixture to obtain the compound ammonium chloride. Example 5

[0021] The compound ammonium chloride was prepared by a hydrothermal method based on the chemical reaction 2NH4Cl + I2O5 + 10HCl = 2NH4ICl2 + 4Cl2 + 5H2O. The specific operation is as follows: a. Accurately weigh 0.243 g NH4Cl and 0.757 g I2O5, and measure 2 ml HCl and 10 ml H2O in a molar ratio of HCl:H2O=1:5. Place the weighed raw materials into a beaker and stir to dissolve. After complete dissolution, transfer the solution to a 25 ml polytetrafluoroethylene (PTFE) liner, and then place the PTFE liner into a high-pressure reactor and seal it. b. Place the sealed high-pressure reactor from step a into an oven and heat it to 180 ℃ at a rate of 3 ℃ / min. Maintain the temperature for 60 h. After washing with deionized water and drying at room temperature, grind the mixture to obtain the compound ammonium chloriodide. Example 6

[0022] The compound ammonium chloride was prepared by a hydrothermal method based on the chemical reaction (NH4)2CO3 + 2HIO3 + 12HCl = 2NH4ICl2 + 4Cl2 + CO2 + 7H2O. The specific operation is as follows: a. Accurately weigh 0.215 g (NH4)2CO3 and 0.785 g HIO3, and measure 2 ml HCl and 14 ml H2O in a molar ratio of HCl:H2O=1:7; place the weighed raw materials into a beaker and stir to dissolve. After complete dissolution, transfer the solution to a 25 ml polytetrafluoroethylene (PTFE) liner, and then place the PTFE liner into a high-pressure reactor and seal it. b. Place the sealed high-pressure reactor from step a into an oven and heat it to 210 ℃ at a rate of 5 ℃ / min. Maintain the temperature for 48 h. After washing with deionized water and drying at room temperature, grind the mixture to obtain the compound ammonium chloride. Example 7

[0023] The rubidium chloride-iodide birefringent optical crystal was grown using a hydrothermal method based on the chemical reaction Rb₂CO₃ + I₂O₅ + 12HCl = 2RbICl₂ + 4Cl₂ + CO₂ + 6H₂O. The specific operation was carried out according to the following steps: a. Accurately weigh 0.224 g Rb2CO3 and 0.776 g I2O5, and measure 6 ml HCl and 18 ml H2O in a molar ratio of HCl:H2O=1:3; place the weighed raw materials into a beaker and stir to dissolve. After complete dissolution, transfer the solution to a 50 ml polytetrafluoroethylene (PTFE) liner, and then place the PTFE liner in a high-pressure reactor and seal it. b. Place the sealed high-pressure reactor from step a into an oven and heat it to 150 °C at a rate of 1 °C / min, hold it at that temperature for 72 h, and then cool it to room temperature at a rate of 0.1 °C / min. During the cooling process, spontaneous crystallization occurs. Collect the liner product, wash it with deionized water, and dry it at room temperature to obtain a product with dimensions of 2.68 × 2.82 × 1.48 mm. 3 A chloro-iodine-rubidium birefringent optical crystal. Example 8

[0024] A rubidium-iodine birefringent optical crystal was grown using a hydrothermal method based on the chemical reaction 2RbCl + I₂O₅ + 10HCl = 2RbICl₂ + 4Cl₂ + 5H₂O. The specific operation was carried out according to the following steps: a. Accurately weigh 0.420 g RbCl and 0.580 g I2O5, and measure 4 ml HCl and 20 ml H2O in a molar ratio of HCl:H2O=1:5. Place the weighed raw materials into a beaker and stir to dissolve. After complete dissolution, transfer the solution to a 50 ml polytetrafluoroethylene (PTFE) liner, and then place the PTFE liner into a high-pressure reactor and seal it. b. Place the sealed high-pressure reactor from step a into an oven and heat it to 180 °C at a rate of 3 °C / min, hold it at that temperature for 60 h, and then cool it to room temperature at a rate of 0.3 °C / min. During the cooling process, spontaneous crystallization occurs. Collect the liner product, wash it with deionized water, and dry it at room temperature to obtain a product with dimensions of 1.86 × 3.67 × 1.46 mm. 3 A chloro-iodine-rubidium birefringent optical crystal. Example 9

[0025] The rubidium chloride-iodide birefringent optical crystal was grown using a hydrothermal method based on the chemical reaction Rb₂CO₃ + 2HIO₃ + 12HCl = 2RbICl₂ + 4Cl₂ + CO₂ + 7H₂O. The specific operation was carried out according to the following steps: a. Accurately weigh 0.396 g Rb2CO3 and 0.604 g HIO3, and measure 4 ml HCl and 28 ml H2O in a molar ratio of HCl:H2O=1:7; place the weighed raw materials into a beaker and stir to dissolve. After complete dissolution, transfer the solution to a 50 ml polytetrafluoroethylene (PTFE) liner, and then place the PTFE liner into a high-pressure reactor and seal it. b. Place the sealed high-pressure reactor from step a into an oven and heat it to 210 °C at a rate of 5 °C / min, hold it at that temperature for 48 h, and then cool it to room temperature at a rate of 0.5 °C / min. During the cooling process, spontaneous crystallization occurs. Collect the liner product, wash it with deionized water, and dry it at room temperature to obtain a product with dimensions of 4.58 × 3.69 × 1.22 mm. 3 A chloro-iodine-rubidium birefringent optical crystal. Example 10

[0026] The ammonium chloride-iodide birefringent optical crystal was grown using the hydrothermal method based on the chemical reaction 2NH4HCO3 + I2O5 + 12HCl = 2NH4ICl2 + 4Cl2 + 2CO2 + 7H2O. The specific operation was carried out according to the following steps: a. Accurately weigh 0.191g NH4HCO3 and 0.809g I2O5, and measure 6 ml HCl and 18 ml H2O in a molar ratio of HCl:H2O=1:3; place the weighed raw materials into a beaker and stir to dissolve. After complete dissolution, transfer the solution to a 50 ml polytetrafluoroethylene (PTFE) liner, and then place the PTFE liner in a high-pressure reactor and seal it. b. Place the sealed high-pressure reactor from step a into an oven and heat it to 150 °C at a rate of 1 °C / min, hold it at that temperature for 72 h, and then cool it to room temperature at a rate of 0.1 °C / min. During the cooling process, spontaneous crystallization occurs. Collect the liner product, wash it with deionized water, and dry it at room temperature to obtain a product with dimensions of 1.68 × 3.42 × 1.02 mm. 3 Ammonium chloride-iodide birefringent optical crystal. Example 11

[0027] An ammonium chloride-iodide birefringent optical crystal was grown using the hydrothermal method based on the chemical reaction 2NH4Cl + I2O5 + 10HCl = 2NH4ICl2 + 4Cl2 + 5H2O. The specific operation was carried out according to the following steps: a. Accurately weigh 0.243 g NH4Cl and 0.757 g I2O5, and measure 4 ml HCl and 20 ml H2O in a molar ratio of HCl:H2O=1:5. Place the weighed raw materials into a beaker and stir to dissolve. After complete dissolution, transfer the solution to a 50 ml polytetrafluoroethylene (PTFE) liner, and then place the PTFE liner into a high-pressure reactor and seal it. b. Place the sealed high-pressure reactor from step a into an oven and heat it to 180 °C at a rate of 3 °C / min, hold it at that temperature for 60 h, and then cool it to room temperature at a rate of 0.3 °C / min. During the cooling process, spontaneous crystallization occurs. Collect the liner product, wash it with deionized water, and dry it at room temperature to obtain a product with dimensions of 3.18 × 1.42 × 1.46 mm. 3 Ammonium chloride-iodide birefringent optical crystal. Example 12

[0028] An ammonium chloride-iodide birefringent optical crystal was grown using the chemical reaction (NH4)2CO3 + 2HIO3 + 12HCl = 2NH4ICl2 + 4Cl2 + CO2 + 7H2O. The specific operation was carried out according to the following steps: a. Accurately weigh 0.215 g (NH4)2CO3 and 0.785 g HIO3, and measure 4 ml HCl and 28 ml H2O in a molar ratio of HCl:H2O=1:7; place the weighed raw materials into a beaker and stir to dissolve. After complete dissolution, transfer the solution to a 50 ml polytetrafluoroethylene (PTFE) liner, and then place the PTFE liner into a high-pressure reactor and seal it. b. Place the sealed high-pressure reactor from step a into an oven and heat it to 210 °C at a rate of 5 °C / min, hold it at that temperature for 48 h, and then cool it to room temperature at a rate of 0.5 °C / min. During the cooling process, spontaneous crystallization occurs. Collect the liner product, wash it with deionized water, and dry it at room temperature to obtain a product with dimensions of 1.24 × 4.16 × 2.02 mm. 3 Ammonium chloride-iodide birefringent optical crystal. Example 13

[0029] A rubidium chloride-iodide birefringent optical crystal was grown using the chemical reaction Rb₂CO₃ + I₂O₅ + 12HCl = 2RbICl₂ + 4Cl₂ + CO₂ + 6H₂O at room temperature via solvent evaporation. The specific operation was carried out according to the following steps: a. Accurately weigh 0.409 g Rb2CO3 and 0.591 g I2O5, and measure 6 ml HCl and 18 ml H2O in a molar ratio of HCl:H2O=1:3; place the weighed raw materials in a clean glass beaker and stir at room temperature until completely dissolved to obtain a mixed solution; b. Let the mixed solution from step a stand, filter to remove insoluble matter, transfer the clear filtrate to a wide-mouth crystallizing dish, cover the mouth of the container with a membrane with micropores, and allow the solvent to slowly evaporate naturally at room temperature and in a vibration-free environment. c. After evaporating the solution from step b until supersaturation occurs, crystals gradually precipitate and grow over 21 days, yielding crystals with dimensions of 4.62 × 3.20 × 1.18 mm. 3 A chloro-iodine-rubidium birefringent optical crystal. Example 14

[0030] A rubidium-iodine birefringent optical crystal was grown using the room-temperature solvent evaporation method based on the chemical reaction 2RbCl + I₂O₅ + 10HCl = 2RbICl₂ + 4Cl₂ + 5H₂O. The specific operation was carried out according to the following steps: a. Accurately weigh 0.420 g RbCl and 0.580 g I2O5, and measure 4 ml HCl and 20 ml H2O in a molar ratio of HCl:H2O=1:5; place the weighed raw materials in a clean glass beaker and stir at room temperature until completely dissolved to obtain a mixed solution; b. Let the mixed solution from step a stand, filter to remove insoluble matter, transfer the clear filtrate to a wide-mouth crystallizing dish, cover the mouth of the container with filter paper with micropores, and allow the solvent to slowly evaporate naturally at room temperature and in a vibration-free environment. c. After evaporating the solution from step b until supersaturation occurs, crystals gradually precipitate and grow over 17 days, yielding crystals with dimensions of 5.62 × 2.60 × 1.46 mm. 3 A chloro-iodine-rubidium birefringent optical crystal. Example 15

[0031] A rubidium chloride-iodide birefringent optical crystal was grown using the room-temperature solvent evaporation method based on the chemical reaction Rb₂CO₃ + 2HIO₃ + 12HCl = 2RbICl₂ + 4Cl₂ + CO₂ + 7H₂O. The specific operation was carried out according to the following steps: a. Accurately weigh 0.396 g Rb2CO3 and 0.604 g HIO3, and measure 4 ml HCl and 28 ml H2O in a molar ratio of HCl:H2O=1:7; place the weighed raw materials in a clean glass beaker and stir at room temperature until completely dissolved to obtain a mixed solution; b. Let the mixed solution in step b stand, filter to remove insoluble matter, transfer the clear filtrate to a wide-mouth crystallizing dish, cover the mouth of the container with a membrane with micropores, and allow the solvent to slowly evaporate naturally at room temperature and in a vibration-free environment. c. After evaporating the solution from step b until supersaturation occurs, crystals gradually precipitate and grow over 14 days, yielding crystals with dimensions of 2.62 × 2.60 × 1.46 mm. 3 A chloro-iodine-rubidium birefringent optical crystal. Example 16

[0032] An ammonium chloride-iodide birefringent optical crystal was grown using the chemical reaction 2NH4HCO3 + I2O5 + 12HCl = 2NH4ICl2 + 4Cl2 + 2CO2 + 7H2O, employing a room-temperature solvent evaporation method. The specific operation was carried out according to the following steps: a. Accurately weigh 0.191 g NH4HCO3 and 0.809 g I2O5, and measure 6 ml HCl and 18 ml H2O in a molar ratio of HCl:H2O = 1:3; place the weighed raw materials in a clean glass beaker and stir at room temperature until completely dissolved to obtain a mixed solution; b. Let the solution from step a stand, filter it to remove insoluble matter, transfer the clear filtrate to a wide-mouth crystallizing dish, cover the mouth of the container with filter paper with micropores, and allow the solvent to slowly evaporate naturally at room temperature and in a vibration-free environment. c. After evaporating the solution from step b until supersaturation occurs, crystals gradually precipitate and grow over 21 days, yielding crystals with dimensions of 3.12 × 1.60 × 2.46 mm. 3 Ammonium chloride-iodide birefringent optical crystal. Example 17

[0033] An ammonium chloride-iodide birefringent optical crystal was grown using the room-temperature solvent evaporation method based on the chemical reaction 2NH4Cl + I2O5 + 10HCl = 2NH4ICl2 + 4Cl2 + 5H2O. The specific operation was carried out according to the following steps: a. Accurately weigh 0.243 g NH4Cl and 0.757 g I2O5, and measure 4 ml HCl and 20 ml H2O in a molar ratio of HCl:H2O=1:5. Place the weighed raw materials in a clean glass beaker and stir at room temperature until completely dissolved to obtain a mixed solution. b. Let the mixed solution from step a stand, filter to remove insoluble matter, transfer the clear filtrate to a wide-mouth crystallizing dish, cover the mouth of the container with a membrane with micropores, and allow the solvent to slowly evaporate naturally at room temperature and in a vibration-free environment. c. After evaporating the solution from step b until supersaturation occurs, crystals gradually precipitate and grow over 17 days, yielding crystals with dimensions of 4.12 × 2.88 × 2.02 mm. 3 Ammonium chloride-iodide birefringent optical crystal. Example 18

[0034] An ammonium chloride-iodide birefringent optical crystal was grown using the chemical reaction (NH4)2CO3 + 2HIO3 + 12HCl = 2NH4ICl2 + 4Cl2 + CO2 + 7H2O, employing a room-temperature solvent evaporation method. The specific operation was carried out according to the following steps: a. Accurately weigh 0.215 g (NH4)2CO3 and 0.785 g HIO3, and measure 4 ml HCl and 28 ml H2O in a molar ratio of HCl:H2O=1:7; place the weighed raw materials in a clean glass beaker and stir at room temperature until completely dissolved to obtain a mixed solution; b. Let the solution from the mixed solution in step a stand, filter it to remove insoluble matter, transfer the clear filtrate to a wide-mouth crystallizing dish, cover the mouth of the container with filter paper with micropores, and allow the solvent to slowly evaporate naturally at room temperature and in a vibration-free environment. c. After evaporating the solution from step b until supersaturation occurs, crystals gradually precipitate and grow over 14 days, yielding crystals with dimensions of 3.12 × 6.68 × 1.62 mm. 3 Ammonium chloride-iodide birefringent optical crystal. Example 19

[0035] A Glan prism is made from any of the rubidium chloride / ammonium chloride infrared birefringent optical crystals from Examples 7-18: The birefringent crystal is processed into two identical crystal prisms. Figure 6 The prisms are designed such that their optical axes are perpendicular to the incident light, and the incident plane contains the other two crystallographic axes of the crystal. The inclined planes of the two prisms are connected by a thin layer of air or an optical adhesive layer with different refractive indices, forming polarizing prism structures with different apex angles. By adjusting the prism apex angle, the prism can be designed specifically for the crystal's light transmission range. When a beam of light enters the prism perpendicularly to the incident plane, in the first prism, the two polarized beams with mutually perpendicular vibration directions maintain their original propagation directions, and their incident angle at the inclined plane is exactly equal to the prism apex angle (i.e., the angle between the inclined plane and the right-angled plane). By rationally designing the prism apex angle, one beam of polarized light can undergo total internal reflection at the inclined plane, while the other beam of polarized light passes through the intermediate connecting layer and enters the second prism, ultimately exiting along the exit direction. Example 20

[0036] Wollaston prisms were fabricated using any of the rubidium chloride-iodide / ammonium chloride-iodide birefringent crystals from Examples 7-18. The crystal is processed into two prisms with the same vertices but different crystallographic axes, and then bonded together to form a Wollaston prism. Figure 7 When incident light enters the end face of a prism perpendicularly, within the first prism, two polarized beams with mutually perpendicular vibration directions propagate in the same direction but at different speeds due to their different refractive indices. When the light enters the second prism from the first, the refractive indices of the two beams change due to the 90° rotation of the crystallographic axis of the second prism relative to the incident direction, causing them to separate due to birefringence. Subsequently, when they enter air from the second prism, birefringence occurs again, further widening the separation angle. The greater the birefringence of the crystal itself, the more pronounced the beam separation, and the more advantageous it is for achieving effective polarization-based beam splitting. Example 21

[0037] A polarization beam splitter was fabricated using any of the rubidium chloride / ammonium chloride birefringent crystals from Examples 7-18: A polarization beam splitter can be fabricated using a wedge-shaped birefringent crystal, as shown in the schematic diagram below. Figure 8 As shown, the crystal wedge angle is set along its y-axis. When a beam of natural light is incident along the y-axis (i.e., the direction of the optical principal axis), it is separated into two linearly polarized beams with mutually perpendicular vibration directions inside the crystal. This separation effect originates from the birefringence property of the crystal: the greater the birefringence, the more obvious the spatial separation distance between the two beams upon exiting, which is more beneficial for beam separation and collection in practical applications. Example 22

[0038] An optical isolator was fabricated using any of the rubidium chloride / ammonium chloride birefringent crystals from Examples 7-18: An optical isolator can be constructed by adding a Faraday rotator that rotates the polarization plane of the incident light by 45° between a pair of birefringent crystal deflectors placed at a 45° angle. This device allows only forward-propagating light beams to pass through, while effectively blocking backward-propagating light beams. Figure 9 a illustrates the transmission process of a normally incident light beam. Figure 9 b shows the state where reflected light is blocked.

Claims

1. A compound rubidium chloride and ammonium chloride, characterized in that, The compounds have the chemical formulas RbICl2 and NH4ICl2, with molecular weights of 283.27 and 215.84, respectively. Both crystallize in an orthorhombic crystal system with space group [missing information]. Pnma, The cell parameters of RbICl2 are a = 10.1376(18) Å, b = 6.2403(15) Å, c = 8.4701(18) Å, α = β = γ =90°, V = 535.83(20) Å 3 The cell parameters of NH4ICl2 are: a = 10.145(7), b = 6.155(4) Å, c =8.451(4) Å, α = β = γ = 90°, V = 527.70(56) Å 3 Both are yellow crystals with centrosymmetric structures. The structure of rubidium chloride-iodide consists of linear [ICl2] units and [RbCl8] polyhedra; the structure of ammonium chloride-iodide consists of linear [ICl2] units and [NH4] tetrahedra.

2. A rubidium chloride-iodide and ammonium chloride-iodide infrared birefringent optical crystal, characterized in that, The crystals have the chemical formulas RbICl2 and NH4ICl2, with molecular weights of 283.27 and 215.84, respectively. Both crystallize in an orthorhombic crystal system with space group [missing information]. Pnma, The cell parameters of RbICl2 are a = 10.1376(18) Å, b = 6.2403(15) Å, c = 8.4701(18) Å, α = β = γ = 90°, V = 535.83(20) Å 3 The cell parameters of NH4ICl2 are: a = 10.145(7), b = 6.155(4) Å, c =8.451(4) Å, α = β = γ = 90°, V = 527.70(56) Å 3 .

3. The method for preparing the rubidium chloride-iodide and ammonium chloride-iodide birefringent optical crystal according to claim 2, characterized in that, Birefringent optical crystals are prepared using either a hydrothermal method or a room-temperature solvent method. The hydrothermal method was used to prepare rubidium chloride-iodide and ammonium chloride-iodide birefringent optical crystals. The specific operation was carried out according to the following steps: a. Accurately weigh the Rb source / NH3 source, I source, and Cl source. Measure HCl and H2O in a molar ratio of HCl:H2O = 1:

5. Place the weighed raw materials into a beaker and stir to dissolve. After complete dissolution, transfer the solution to a 50 ml polytetrafluoroethylene (PTFE) liner. Then, place the PTFE liner in a high-pressure reactor and seal it. The Rb source material is Rb2CO3, RbI, or RbCl; the I source material is I2O5 or HIO3; the Cl source material is ICl or 12 mol / L hydrochloric acid solution; and the NH3 source material is NH4HCO3, (NH4)2CO3, or NH4Cl. b. Place the high-pressure reactor sealed in step a into an oven and heat it to 150-210℃ at a heating rate of 1-5℃ / min. Hold it at this temperature for 48-72 h. Then cool it down to room temperature at a cooling rate of 0.1-0.5℃ / min. The crystal will spontaneously crystallize during the cooling process to obtain rubidium chloride-iodide and ammonium chloride-iodide birefringent optical crystals. The room-temperature solvent method for growing rubidium chloroiodide and ammonium chloroiodide birefringent optical crystals is carried out according to the following steps: a. Accurately weigh the Rb source / NH3 source, I source, and Cl source, mix them thoroughly and grind them evenly. Measure HCl and H2O in a molar ratio of HCl:H2O = 1:3-7. Place the weighed raw materials into a clean glass beaker and stir at room temperature until completely dissolved to obtain a mixed solution. The Rb source material is Rb2CO3, RbI, or RbCl; the I source material is I2O5 or HIO3; the Cl source material is ICl or 12 mol / L hydrochloric acid solution; and the NH3 source material is NH4HCO3, (NH4)2CO3, or NH4Cl. b. Let the mixed solution from step a stand, filter to remove insoluble matter, transfer the clear filtrate to a wide-mouth crystallizing dish, cover the container mouth with a membrane or filter paper with micropores, and allow the solvent to slowly evaporate naturally at room temperature and in a vibration-free environment. c. After the solution in step b evaporates to the point of supersaturation, the crystal will gradually precipitate and grow over two to three weeks, yielding rubidium chloride and ammonium chloride birefringent optical crystals.

4. The use of the rubidium chloride-iodide and ammonium chloride-iodide birefringent optical crystals as described in claim 3 in the preparation of polarization beam splitters such as Glan prisms, Wollaston prisms, and Lochon prisms, as well as optical devices such as optical isolators, circulators, and beam shifters.

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