Be2BO3F: A Phase of Beryllium Fluoride Borate Derived from

Jun 22, 2016 - A new phase of beryllium fluoride borate Be2BO3F was discovered. Its structure features infinite planar [Be2BO3F2]∞ layers, which are...
4 downloads 9 Views 3MB Size
Download PDF
Article pubs.acs.org/IC

Be2BO3F: A Phase of Beryllium Fluoride Borate Derived from KBe2BO3F2 with Short UV Absorption Edge Shu Guo,†,‡ Lijuan Liu,*,† Mingjun Xia,† Lei Kang,†,‡ Qian Huang,†,‡ Chao Li,†,‡ Xiaoyang Wang,† Zheshuai Lin,† and Chuangtian Chen† †

Beijing Center for Crystal Research and Development, Key Laboratory of Functional Crystals and Laser Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China ‡ University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China S Supporting Information *

ABSTRACT: A phase of beryllium fluoride borate Be2BO3F (BBF) was successfully developed and grown by spontaneous nucleation from high temperature solution. The crystal belongs to the trigonal space group of R3̅c (No. 167), with lattice parameters a = 4.442(1) Å, c = 24.956(5) Å, and Z = 2. It is constructed by the infinite planar [Be2BO3F2]∞ layers, in which the planar triangle [BO3]3− and the tetrahedral [BeO3F]5− anionic groups are arranged in parallel via cornersharing O atoms in each ab plane. BBF is an incongruent compound and decomposes at about 650 °C. The deepultraviolet (DUV) transmittance spectrum reveals that its UV cutoff wavelength is down to ∼150 nm. Theoretical calculations show that BBF has a large birefringence (Δn = 0.13 at 200 nm), which mainly originates from the infinite planar [Be2BO3F2]∞ layers. In conclusion, BBF may be served as a potential DUV birefringent material.

■

INTRODUCTION Deep-ultraviolet (DUV) coherent light sources (λ < 200 nm) play a key role in advanced science and technology owing to their potential applications in photolithography, laser cooling, attosecond pulse generation, as well as high resolution photoemission spectrometers.1 It is generally known that the most efficient way to produce DUV lasers is by using a nonlinear optical (NLO) crystal through a cascaded frequency conversion process.2 Currently, beryllium borates were found to be applicable in the DUV NLO crystals.3 For example, ABe2BO3F2 (A = K, Rb)4 are the only two DUV NLO crystals that could produce 177.3 and 193.0 nm coherent laser by a direct second harmonic generation (SHG) method. They both have wide transmittance spectra from near IR to DUV region (150−3500 nm). A special prism-coupling technique (PCT) was developed to avoid cutting the crystal along the phasematching angle. The 177.3 nm laser produced by KBBF-PCT has been successfully used in modern instruments such as angle resolved photoemission spectroscopy (ARPES). Encouragingly, many novel physical phenomena were revealed with these advanced instruments, which have never been observed by other traditional techniques.1f,5 However, the KBBF crystal has a serious layering growth habit along the c axis due to the weak K+−F− ionic bonds between interlayers, which hinder growth of thick crystals in the c axis. So the as-grown crystals are plate-like on the millimeter scale. It arouses the interest of researchers in exploring new DUV NLO crystals in the beryllium borates which could © XXXX American Chemical Society

overcome the layering growth habit. Through the molecular engineering method, our group designed and obtained Sr2Be2B2O7 (SBBO) crystal to improve the layering tendency in KBBF and keep the brilliant optical properties of it.6 The network structure of [Be3B3O6]∞ layers with bridging oxygen atoms bonded to beryllium atoms of adjacent layers have overcome the layering growth habit of KBBF. Unfortunately, the structure of SBBO was not exactly determined, and the quality of grown crystal was poor. Be2BO3F (C2-BBF) compound was first reported as the “intermediate” for synthesizing the KBBF compound by the Soviet scientist I. Baidina in 1978.7 Then, its crystal was obtained by a hydrothermal method, and the structure was successfully solved by single-crystal X-ray diffraction. It crystallized into monoclinic space group C2 (No. 5) with cell parameters a = 7.687(4) Å, b = 4.439(3) Å, c = 8.699(4) Å, β = 107.08°, and V = 283.74 Å3. Then, in 2005 our group obtained the pure phase of C2-BBF powder through conventional solid state methods and carried out a series of preliminary experimental and theoretical studies.8 According to the previous results, C2-BBF was first confirmed to be a potential NLO material for UV and DUV laser generation. However, single crystals have not been obtained from the traditional flux growth. Received: March 26, 2016

A

DOI: 10.1021/acs.inorgchem.6b00755 Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry

■

RESULTS AND DISCUSSION Crystal Growth and Thermal Behavior. As shown in Figure 1, the DSC curve exhibits one broad endothermic peak

In this work, we intended to grow C2-BBF crystals by the flux method and evaluate its NLO properties and a new phase of it, namely, R3̅c-BBF, was unexpectedly obtained. Its crystal growth, structure, thermal behaviors, as well as optical properties are studied for the first time.

■

Article

EXPERIMENTAL SECTION

Crystal Growth of Be2BO3F. NaBF4 (Tianjin Jinke Chemical Reagent Co., Ltd.,AR), BeO (Sinopharm, 2N), LiF (Sinopharm, AR) and H3BO3 (Tianjin Fengchuan Chemical Reagent Co., Ltd., 5N) were used as received. Considering the high toxicity of the BeO powders, a ventilation environment was provided during all the operating processes. Single crystals were obtained from a high temperature self-flux system through spontaneous crystallization. Mixture of NaBF4/BeO/B2O3/LiF with molar ratios of 1−1.5:1− 2:0.5−1.5:1−3 were fully ground and placed in a platinum crucible. First, the mixture was heated in a computer controlled electric furnace at 800 °C for 2 days until the melts became homogeneous. The saturation temperature was estimated by observing the spontaneous nucleation on the surface of the solution (∼730 °C). Then, it was slowly decreased at a rate of 10 °C/day in the process of crystal growth. Finally, the as-grown crystal was obtained by dealing with hot hydrochloric acid for 2 days. Single-Crystal X-ray Diffraction. A colorless crystal (0.21 mm × 0.18 mm × 0.11 mm) was selected and fixed on a glass fiber for singlecrystal X-ray diffraction. The diffraction data was collected on a Gemini E single-crystal diffractometer equipped with a graphitemonochromatic Mo Kα radiation (λ= 0.71073 Å) at 153 K and an Eos CCD detector. Then, the intensity data records, cell refinement, and data reduction were collected with the CrystalClear program. Finally, the structure was analyzed by the direct method and refined by fullmatrix least-squares techniques with SHELXL-97.9 Relevant crystallographic date for R3̅c-BBF are given in Table S1. Selected atomic coordinates, bond distances, and isotropic displacement parameters are deposited in the Tables S2 and 3. Powder X-ray Diffraction (PXRD). The powder samples were characterized by powder X-ray diffraction measurement on a Bruker D8 ADVANCE X-ray diffractometer using Cu Kα radiation (λ = 1.5418 Å) at room temperature in the range 2θ = 5−80°. Thermal Analysis. The thermal properties were measured by the differential scanning calorimetric (DSC) and the thermogravimetric analysis (TGA) using a NETZSCH STA 409C/CD thermal analyzer. In detail, a 14.3 mg powder sample was thoroughly ground, carefully placed in a platinum crucible, and heated from room temperature to 1140 °C at a rate of 10 °C/min in a flowing N2 atmosphere. The remaining melts were examined by PXRD. The powder of Al2O3 was used as standard. IR Spectroscopy. An infrared (IR) spectrum was measured at room temperature by a Bio-Rad FTS-60 FTIR spectrometer in the range 400−4000 cm−1 with a resolution of 1 cm−1. The sample was mixed thoroughly with dried KBr at a mass ratio of 1:100. DUV Transmission Spectrum. The DUV transmission spectrum was recorded at room temperature using a McPherson VUVas2000 spectrophotometer in the wavelength range 120−220 nm. A transparent R3̅c-BBF crystal with size 7.0 × 5.0 × 0.7 mm3 was used for the measurement without polishing. First-Principles Calculations. The first-principles calculations are carried out by the plane-wave pseudopotential method10 implemented in the CASTEP package11 based on the density functional theory.12 The ion−electron interactions are modeled by the optimized normalconserving pseudopotentials for all elements.13 The generalized gradient approximation (GGA) with Perdew−Burke−Ernzerhof (PBE) functionals is adopted.14 The kinetic energy cutoffs of 1000 eV and Monkhorst−Pack k-point meshes15 with spanning of less than 0.04/Å3 in the Brillouin zone are chosen.

Figure 1. DSC curves for R3̅c-BBF.

at about 1023.9 °C during the heating process, but no obvious exothermic peak was observed when cooling down. After cooling down, the analysis of the PXRD pattern of melted residues shows a clear BeO peak and was different from the initial powder (Figure S1), demonstrating the incongruent melting behavior of it. With the heating process, it exhibits decomposition in two steps. The first step occurs in the interval 600−1000 °C, which is attributed to the decomposition of R3̅c-BBF. The second step is attributed to the decomposition of Be3B2O3 and occurs above 1000 °C (Figure S1). The decomposition can be written as follows: Be2BO3F → 1/2Be3B2O6 + 1/2BeF2

(1)

Be3B2O6 → B2O3 + 3BeO

(2)

Hence, the flux method was chosen to grow large crystals of R3̅c-BBF. Transparent crystals up to 7.0 × 5.0 × 0.7 mm3 were obtained by a spontaneous nucleation method using a NaBF4− LiF-B2O3 flux system (Figures 2 and 6). When the R3̅c-BBF crystals were exposed to the wet air for about 15 days, no apparent weight change was found in the crystals. Upon submerging the R3̅c-BBF crystals into the hot hydrochloric solution (∼70 °C, 5%) for about 2 h, the crystals have not been obviously dissolved. So, the crystals remain stable in air and hot diluted hydrochloric acid, indicating that they are non-

Figure 2. Photo of R3c̅ -BBF crystals. B

DOI: 10.1021/acs.inorgchem.6b00755 Inorg. Chem. XXXX, XXX, XXX−XXX

Article

Inorganic Chemistry

Figure 3. Crystal structure of R3̅c-BBF. (a) Unit cell. (b) The infinite lattice layer [Be2BO3F2]∞ (viewed along the c axis). (c) Basic building blocks [BeO3F]5− and [BO3]3−.

Figure 4. Comparison of the crystal structure in (a) hambergite, (b) C2-BBF, (c) R3̅c-BBF, and (d) R32-KBBF.

one crystallographically unique position. The B atoms are surrounded by three O atoms to form a normal triangular [BO3]3− with the B−O distances of 1.371(1) Å and O−B−O bond angles of 120.0(1)° (Figure 3c). The Be atoms are all four-coordinated to from an irregular [BeO3F]5− tetrahedron with the Be−O distance of 1.621(1) Å and Be−F distance of 1.568(1) Å, respectively. As shown in Figure 3b, the infinite lattice [Be2BO3F2]∞ layers in the ab plane with [BO3]3− and

hygroscopic with high chemical stability. Moreover, the layering tendency problem that appeared in KBBF crystal growth has been effectively improved in the growth of R3̅c-BBF. Crystal Structure. The structure of R3̅c-BBF is depicted in Figure 3a. It crystallizes in trigonal symmetry, space group R3̅c, with lattice parameters a = 4.442(1) Å, c = 24.956(5) Å, and Z = 2, and was different from the previously reported C2-BBF structure. In the asymmetric unit, B, Be, O, and F occupy only C

DOI: 10.1021/acs.inorgchem.6b00755 Inorg. Chem. XXXX, XXX, XXX−XXX

Article

Inorganic Chemistry Table 1. Structural Characteristics and Optical Properties of Beryllium Borates crystals R3c̅ -BBF C2-BBF R32-KBBF R3̅c-KBBF a

space group R3c̅ C2 R32 R3̅c

interlayer bridging

crystal growth method

Be−F−Be Be−F−Be K+−F− K+−F−

flux hydrothermal flux hydrothermal

interlayer distances (Å) a

4.159 4.158a 6.248a 6.254a

birefrigence Δnf

UV edge (nm)

0.13a ∼0.13b 0.10c ∼0.10b

∼150a ∼150d ∼147c ∼148e

This work. bData from anionic group theory. cData from ref 2. dData from ref 8. eData from Figure S6. fAt the wavelength of 200 nm.

Figure 5. Project of R3̅c-BBF and R32-KBBF along c.

calculated bond valence of the Be−F bonds in R3̅c-BBF is 0.46, indicating a strong covalent bond.16,21 During our preliminary crystal growth process, layering growth habit has been declined in R3̅c-BBF. As is reported, the excellent NLO properties of KBBF mainly originate from the coplanar [BO3]3− groups in the infinite [Be2BO3F2]∞ layer. Clearly, aligned [Be2BO3F2]∞ layers and high [BO3]3− densities are key factors to obtain a large SHG effect. Unfortunately, R3̅c-BBF consists of the [Be2BO3F2]∞ layers with opposite direction in the [BO3]3− groups between the adjacent layers, which counteract all of the NLO effect (Figure 5). Interestingly, the interlayer distances of R3̅c-BBF are shorter than that in KBBF (Table 1). The strategy of reducing interlayer spacing is beneficial to increase the density of the [BO3]3− and then to obtain the larger NLO effects and birefringence.3d The preliminary theoretical calculation results reveal that the birefringence of R3̅c-BBF is larger than that of KBBF (Table 1). It inspires us to introduce different size and charge of cations or other groups in the interlayers of layered beryllium borates to control the interlayer spacing and the orientation of [BO3]3− groups. Furthermore, considering that different growth conditions may have an effect on the rotation of [BO3]3− groups, the desired Be2BO3F phase with parallel aligned [Be2BO3F2]∞ layers may exist in an appropriate growth condition, and more work is continuing. Physical Characterization. The PXRD pattern of the crystalline R3c̅ -BBF coincided well with that calculated from the single-crystal data (Figure S4). The vibrational spectra of the R3̅c-BBF and R32-KBBF are compared in Figure S5, which confirms that the similar [BO3]3− and [BeO3F]5− groups exist in the two different crystal structures. The strong peaks around 1311.1 cm−1 in the two curves correspond to the B−O stretching vibrations of the [BO3]3− triangles. The bands between 650 and 1000 cm−1 can be classified into the vibrational signature of the [BeO3F]5− tetrahedron.22

[BeO3F]5− anionic groups are arranged in an orderly manner. The bond valence sums (BVS) of each atom in R3c̅ -BBF were calculated to confirm the oxidation states of every atom.16 The results of the bond valence calculation (Be, 2.029; B, 3.08; O, −2.043; F, −0.921) show good agreement with the expected oxidation states. It is known that [BO3]3− and [BO4]5− are the basic building blocks of the borate family.17 Multiple structures were formed by the different connections of [BO3]3− and [BO4]5− groups. On the basis of the anionic group theory,17,18 the [BO3]3− groups in borates have made major contribution to the large birefringence and band gap, which were quite important to a DUV NLO crystal. During our earlier study, we found two phases exist in KBBF crystals, which were obtained by two different growth methods, namely, R32-KBBF and R3̅c-KBBF.19 The structure of R3̅c-BBF was compared with previously reported C2-BBF, Be2BO3(OH)0.96F0.0420 (hambergite, space group Pbca), and KBBF as shown in Figure 4. Interestingly, the layers in R3̅c-BBF are totally different from that found in its hydroxide analogue hambergite. The [Be2BO3F2]∞ layers in both R3̅c-BBF and C2-BBF are nearly arranged in parallel while [Be2BO3(OH)1.92F0.08]∞ layers in hambergite are bended to a wave-like surface to some degree. The layers in hambergite were bridged by sharing OH anions, and the hydrogen bonds link neighboring OH positions. The bond angle of Be−O−Be is 133.38° in hambergite, and the bond angles of Be−F−Be are 178.49° and 180° in C2-BBF and R3c̅ -BBF, respectively (Figure S2). C2-BBF and R3̅c-BBF show the same layers, bridged bonds, and approximate interlayer distances. The optical properties such as birefringence and absorption edge are also very close to each other (Table 1). Unlike the weak K+−F− ionic bonds in KBBF, the layers of R3̅c-BBF are connected by stronger Be−F−Be covalent bonds to form a three-dimensional skeleton structure, which efficiently mitigates the layering growth tendency (Figure 4b,c). Also, the D

DOI: 10.1021/acs.inorgchem.6b00755 Inorg. Chem. XXXX, XXX, XXX−XXX

Article

Inorganic Chemistry As shown in Figure 6, the short UV absorption edge of R3̅cBBF is located at about 150 nm, demonstrating that it may be a promising material in this region.

conduction bands than O and B. Clearly, the electronic transition inside the coplanar [BO3]3− and [BeO3F]5− anionic groups contribute directly to the magnitude of the energy band gaps (the calculated value is about 5.98 eV) for the R3c̅ -BBF crystal.23 Furthermore, the imaginary part of the dielectric function has been calculated from the electronic transition from the VB to CB caused by the interaction with photons according to the obtained electronic structures. Consequently, the real part of the dielectric function is determined by a Kramers− Kronig transform. Then, the refractive indices n (and the birefringence Δn) are calculated, as plotted in Figure 8. The

Figure 6. DUV transmission spectrum of R3̅c-BBF.

Theoretical Calculations. As shown in Figure 7, the partial density of states (PDOS) of R3̅c-BBF was used to discuss the Figure 8. Calculated dispersion curves of refractive index of R3c̅ -BBF.

refractive indices curves display strong anisotropy and have a tendency for no > ne, indicating R3̅c-BBF is a negative uniaxial crystal. The theoretical calculations indicates that R3̅c-BBF possesses a large birefringence (Δn = no − ne = 0.20−0.13 from 150 to 200 nm). It is worth mentioning that the same calculated method was successfully applied in the KBBF family and obtained good agreement between theoretical and experimental values.23 As a potential DUV birefringent material, the following three minimum requirements are prerequisites: (1) a relatively large birefringence (>0.1), (2) wide transmittance from DUV to IR region, and (3) good chemical and mechanical stability and ease of growth.24 To further evaluate the birefringence performance of R3̅c-BBF in the DUV region, it is compared with that of the commercially successful birefringent crystal aBBO.25 According to our theoretical calculations, R3̅c-BBF displays a large birefringence (Δn = 0.13 at 200 nm) comparable to that of commercial a-BBO (Δn > 0.10) . In addition, R3̅c-BBF maintains the favorable structural features of KBBF, which extends the UV cutoff edge to 150 nm (29 nm shorter than α-BBO).26 Moreover, the adjacent [Be2BO3F2]∞ layers in R3̅c-BBF were connected by stronger Be−F−Be bonds compared with the weak K+−F− ionic bonds in KBBF, thus mitigating the layering growth tendency in the former crystal to some extents. During our preliminary trials of crystal growth, R3̅c-BBF crystals with the dimensions of 7.0 × 5.0 × 0.7 mm3 were obtained, much thicker than the KBBF in the initial growth stage (0.3 mm).27 On the basis of the above results, one may conclude that R3̅c-BBF may find the applications as birefringence crystals in the DUV region.

Figure 7. Partial density of states (PDOS) of R3̅c-BBF.

internal causes of optical properties. Accordingly, some characteristic were deduced from Figure 7 in detail as follows. First, the bands lower than −15 eV are mainly occupied by the s orbitals in the inner electronic shells. Specifically, the O 2s and F 2s orbitals are strongly localized at about −17 and −20 eV, respectively, and are free of interaction with the adjacent atoms. Then, the region of the valence band (VB) between −10 and 0 eV is mostly composed of the p orbitals of the constituent atoms. The upper part of the VB is mainly made up of the O 2p and F 2p orbitals atoms, in which the orbitals of B and Be atoms have made relatively small contributions. However, the O orbitals have dominant contributions to the VB maximum. Next, the conduction band (CB) bottoms are mainly occupied by valence orbitals of O and B atoms, while the Be 2p orbitals have less contribution to the upper

■

CONCLUSIONS A phase of Be2BO3F with space group R3̅c was obtained from the high temperature flux method by spontaneous nucleation for the first time. Its structure is composed of two-dimensional [Be2BO3F2]∞ layers bridged with strong F−Be−F covalent E

DOI: 10.1021/acs.inorgchem.6b00755 Inorg. Chem. XXXX, XXX, XXX−XXX

Article

Inorganic Chemistry bonds. The perfectly parallel [BO3]3− planar units in the ab plane make major contribution to anisotropic polarizabilities, thus generating a large birefringence (Δn = 0.20−0.13 in the range of 150−200 nm) by theoretical calculation. The as-grown crystal shows a better growth habit without a layering tendency. The incongruent melting behavior of the crystal was confirmed by DSC and PXRD. Moreover, the transmission spectrum indicates the UV absorption edge of the crystal is down to 150 nm. To our understanding it may be a potential DUV birefringent material.

■

(6) Chen, C.; Wang, Y.; Wu, B.; Wu, K.; Zeng, W.; Yu, L. Nature 1995, 373, 322−324. (7) Baidina, I.; Bakakin, V.; Podberezskaya, N.; Alekseev, V.; Batsanova, L.; Pavlyuchenko, V. J. Struct. Chem. 1978, 19, 105−108. (8) Wenbing, X.; Zhe-shuai, L.; Yi-cheng, W.; Chuang-tian, C. J. Synthetic Cryst. 2005, 34, 597−600. (9) Sheldrick, G. SHELXS-97, Program for Crystal Structure Solution; University of Göttingen: Göttingen, Germany, 1997. (10) Payne, M. C.; Teter, M. P.; Allan, D. C.; Arias, T.; Joannopoulos, J. Rev. Mod. Phys. 1992, 64, 1045. (11) Clark, S. J.; Segall, M. D.; Pickard, C. J.; Hasnip, P. J.; Probert, M. I.; Refson, K.; Payne, M. C. Z. Kristallogr. - Cryst. Mater. 2005, 220, 567−570. (12) Hohenberg, P.; Kohn, W.; Sham, L. J. Phys. Rev. 1965, 140, 1133. (13) Rappe, A. M.; Rabe, K. M.; Kaxiras, E.; Joannopoulos, J. Phys. Rev. B: Condens. Matter Mater. Phys. 1990, 41, 1227. (14) Perdew, J. P.; Wang, Y. Phys. Rev. B: Condens. Matter Mater. Phys. 1992, 45, 13244. (15) Monkhorst, H. J.; Pack, J. D. Phys. Rev. B 1976, 13, 5188. (16) (a) Brown, I. D.; Altermatt, D. Acta Crystallogr., Sect. B: Struct. Sci. 1985, 41, 244−247. (b) Brese, N. E.; O'Keeffe, M. Acta Crystallogr., Sect. B: Struct. Sci. 1991, 47, 192−197. (c) O'Keeffe, M.; Brese, N. E. Acta Crystallogr., Sect. B: Struct. Sci. 1992, 48, 152−154. (17) (a) Chen, C. T.; et al. Nolinear Optical Borate Crystal; WileyVCH: Germany, 2012. (b) Becker, P. Adv. Mater. 1998, 10, 979−992. (18) Chen, C.; Lin, Z.; Wang, Z. Appl. Phys. B: Lasers Opt. 2005, 80, 1−25. (19) (a) Xu, T.; Liu, L.; Wang, X.; Chen, C.; Zhou, H.; He, X.; Zhang, C.; Sun, J. Dalton Trans. 2014, 43, 16411−5. (b) Yu, J.; Liu, L.; Jin, S.; Zhou, H.; He, X.; Zhang, C.; Zhou, W.; Wang, X.; Chen, X.; Chen, C. J. Solid State Chem. 2011, 184, 2790−2793. (20) Gatta, G.; McIntyre, G. J.; Bromiley, G.; Guastoni, A.; Nestola, F. Am. Mineral. 2012, 97, 1891−1897. (21) Brese, N.; O’keeffe, M. Acta Crystallogr., Sect. B: Struct. Sci. 1991, 47, 192−197. (22) Weir, C. J. Res. Natl. Bur. Stand., Sect. A 1966, 70, 153−164. (23) Kang, L.; Luo, S.; Huang, H.; Zheng, T.; Lin, Z.; Chen, C. J. Phys.: Condens. Matter 2012, 24, 335503. (24) (a) Zhang, H.; Zhang, M.; Pan, S.; Yang, Z.; Wang, Z.; Bian, Q.; Hou, X.; Yu, H.; Zhang, F.; Wu, K.; Yang, F.; Peng, Q.; Xu, Z.; Chang, K. B.; Poeppelmeier, K. R. Cryst. Growth Des. 2015, 15 (1), 523−529. (b) Wang, X.; Xia, M.; Li, R. K. Opt. Mater. 2014, 38, 6−9. (25) Appel, R.; Dyer, C. D.; Lockwood, J. N. Appl. Opt. 2002, 41 (13), 2470−2480. (26) (a) Wu, S.; Wang, G.; Xie, J.; Wu, X.; Zhang, Y.; Lin, X. J. Cryst. Growth 2002, 245 (1), 84−86. (b) Guoqing, Z.; Jun, X.; Xingda, C.; Heyu, Z.; Siting, W.; Ke, X.; Peizhen, D.; Fuxi, G. J. Cryst. Growth 1998, 191 (3), 517−519. (27) Chen, C.; Wu, B.; Wang, Y.; Wenrong, Z.; Mei, L.; Yu, L.; Xia, Y.; Tang, D.; Wu, K. J. Appl. Phys. 1995, 77, 2268−2272.

ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.inorgchem.6b00755. Crystallographic data for Be2BO3F (CIF) Additional data and figures showing coordination environment and 3D framework (PDF)

■

AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. Notes

The authors declare no competing financial interest.

■

ACKNOWLEDGMENTS This work is supported by grants from the National Natural Science Foundation of China (51132008, 61138004, 51402316, 51502307), and the National Instrumentation Program (2012YQ120048).

■

REFERENCES

(1) (a) Cyranoski, D. Nature 2009, 457, 953−955. (b) Schaeffer, R. D.; Hannon, T. Laser Foc. 2001, 37, 115−120. (c) Chen, C.; Xu, Z.; Deng, D.; Zhang, J.-y.; Wong, G.; Wu, B.; Ye, N.; Tang, D. Appl. Phys. Lett. 1996, 68, 2930−2932. (d) Kiss, T.; Kanetaka, F.; Yokoya, T.; Shimojima, T.; Kanai, K.; Shin, S.; Onuki, Y.; Togashi, T.; Zhang, C.; Chen, C.; Watanabe, S. Phys. Rev. Lett. 2005, 94, 057001. (e) Yatsenko, L.; Shore, B.; Halfmann, T.; Bergmann, K.; Vardi, A. Phys. Rev. A: At., Mol., Opt. Phys. 1999, 60, R4237. (f) Kiss, T.; Shimojima, T.; Kanetaka, F.; Kanai, K.; Yokoya, T.; Shin, S.; Onuki, Y.; Togashi, T.; Zhang, C.; Chen, C.; Watanabe, S. J. Electron Spectrosc. Relat. Phenom. 2005, 144, 953−956. (g) Sekikawa, T.; Kosuge, A.; Kanai, T.; Watanabe, S. Nature 2004, 432, 605−608. (h) Keszler, D. A. Curr. Opin. Solid State Mater. Sci. 1996, 1, 204−211. (2) Chen, C. T.; Wang, G. L.; Wang, X. Y.; Xu, Z. Y. Appl. Phys. B: Lasers Opt. 2009, 97, 9−25. (3) (a) Kang, L.; Luo, S.; Peng, G.; Ye, N.; Wu, Y.; Chen, C.; Lin, Z. Inorg. Chem. 2015, 54 (22), 10533−10535. (b) Huang, H.; Yao, J.; Lin, Z.; Wang, X.; He, R.; Yao, W.; Zhai, N.; Chen, C. Angew. Chem., Int. Ed. 2011, 50 (39), 9141−9144. (c) Wang, X.; Liu, L.; Wang, X.; Bai, L.; Chen, C. CrystEngComm 2015, 17 (4), 925−929. (d) Huang, H.; Liu, L.; Jin, S.; Yao, W.; Zhang, Y.; Chen, C. J. Am. Chem. Soc. 2013, 135 (49), 18319−18322. (e) Yan, X.; Luo, S. Y.; Lin, Z. S.; Yao, J. Y.; He, R.; Yue, Y. C.; Chen, C. T. Inorg. Chem. 2014, 53, 1952−1954. (f) Wang, S. C.; Ye, N. J. Am. Chem. Soc. 2011, 133, 11458−11461. (4) (a) Chen, C.; Wang, G.; Wang, X.; Xu, Z. Appl. Phys. B: Lasers Opt. 2009, 97, 9−25. (b) Huang, H.; Chen, C.; Wang, X.; Zhu, Y.; Wang, G.; Zhang, X.; Wang, L.; Yao, J. J. Opt. Soc. Am. B 2011, 28, 2186−2190. (c) Mei, L.; Wang, Y.; Chen, C. Mater. Res. Bull. 1994, 29, 81−87. (d) Chen, C.; Luo, S.; Wang, X.; Wang, G.; Wen, X.; Wu, H.; Zhang, X.; Xu, Z. J. Opt. Soc. Am. B 2009, 26, 1519−1525. (5) Zhang, W.; Liu, G.; Zhao, L.; Liu, H.; Meng, J.; Dong, X.; Lu, W.; Wen, J.; Xu, Z.; Gu, G.; et al. Phys. Rev. Lett. 2008, 100, 107002. F

DOI: 10.1021/acs.inorgchem.6b00755 Inorg. Chem. XXXX, XXX, XXX−XXX