# Fileset [JJAP-AlLB14 (L=Li or Na) 修正済.docx](https://mdr.nims.go.jp/filesets/df58ef6d-f483-4ec6-a1a6-9beb71e7d71b/download) ## Creator Takeshi Hagiwara, Kaoru Kouzu, Shigeru Okada, Akiko Nomura, Kunio Yubuta, Toetsu Shishido, Akira Yoshikawa, [Takao Mori](https://orcid.org/0000-0003-2682-1846) ## Rights This is the version of the article before peer review or editing, as submitted by an author to Japanese Journal of Applied Physics.  IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it.  The Version of Record is available online at https://dx.doi.org/10.35848/1347-4065/ad6659[In Copyright](http://rightsstatements.org/vocab/InC/1.0/) ## Other metadata [Syntheses of AlLB14(L=Li or Na) crystals using alkali fluorides and its properties](https://mdr.nims.go.jp/datasets/76dfe81f-53ff-4f51-a77c-7136874af956) ## Fulltext Syntheses of AlLB14 (L=Li or Na) crystals using alkali fluorides and its propertiesTakeshi Hagiwara, Kaoru Kouzu1,*, Shigeru Okada, Akiko Nomura2, Kunio Yubuta3, Toetsu Shishido2, Akira Yoshikawa2 and Takao Mori4Faculty of Engineering, Kanagawa University, 3-27-1 Rokkakubashi, Kanagawa-ku, Yokohama 221-8686, Japan1Faculty of Science and Engineering, Kokushikan University, 4-28-1 Setagaya, Setagaya-ku, Tokyo 154-8515, Japan 2Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan3Faculty of Engineering, Kyushu University,744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan4Materials Nanoarchitechtonics Center, National Institute for Materials Science (NIMS), Namiki, Tsukuba, Ibaraki 305-0044, JapanAlLB14 (L=Li or Na or K) crystals were grown using LiF or NaF or KF and crystalline boron powders as the starting materials using high-temperature Al melt at soaking temperature 1573~1773 K for soaking time 5 h under an Ar atmosphere. A new compound AlNaB14 and AlLiB14 crystals were obtained from LiF or NaF and B powders, and the atomic ratios (n=B/L=2.0~4.0) of starting materials. AlKB14 crystal was not obtained from KF and B powders as starting materials. The micro-Vickers hardness of AlLB14 crystals is 24(±1) GPa for AlLiB14 and 25(±1) GPa for AlNaB14. The oxidation initiation temperature of AlLiB14 was about 815 K, and the peak due to the exothermic reaction was about 960 K for AlLiB14 and about 990 K for AlNaB14. The final oxidation products were Li2B2O4, Al4B2O9, B2O3 and amorphous phases. The values for the electrical resistivity of the AlLB14 compound were 2.4~157 Ω·cm. *Present address: Faculty of Science and Engineering, Kokushikan University, 4-28-1 Setagaya, Setagaya-ku, Tokyo 154-8515, Japan.*email: kouzu@kokushikan.ac.jp1. IntroductionIn the ternary Al-L-B (L=Li or Na) system, one type of ternary structure, namely AlLB14 with AlMgB14-type (orthorhombic; space group Imma) have been reported.1~3) Higher borides containing the B12 icosahedron unit have been studied because of their many interesting properties, including potential applications to thermoelectric materials and photodetectors.4) In the case of higher borides, it may be difficult to synthesize from the alkali metal-B-Al system by arc-melting method. However, the ternary borides AlLB14 have yet been fully studied well, and there is little information about the physical and chemical properties of AlLB14. Crystal of the ternary boride AlLiB14 is obtained by adding relatively large amount of Li metal.1,5,6) But, owing to the high vapor pressure of Li at high temperature, optimum conditions for growing AlLiB14 crystal are not established. Formerly we successfully prepared single crystals of the ternary borides AlLB14 (L=Li or Na) from the high-temperature Al melt using Li2B4O7 or Na2B4O7 and boron powders as the raw materials.7~10) Here, AlNaB14 crystal is a new compound found by the authors earlier.8~10) In addition, the magnetic susceptibility, microhardness, and oxidation resistance of ALiB14 and AlNaB14 were measured. The temperature dependence of the magnetic susceptibility was measured down to 2 K. The measured magnetic susceptibility of AlLB14 was -4.4×10-7 emu/g for AlLiB14 and -4.0×10-7 emu/g for AlNaB14, which were the same value at room temperature,9,11) and shows an increase at low temperatures indicative of the paramagnetic contribution, which we attribute to impurities.9,11) In addition, the syntheses of AlLB14 compounds from metal salts or oxides or metal carbonates and boron powders were reported using the same melt.11,12) Authors found that AlLB14 can be synthesized from alkali fluoride and boron element. In this paper, we report the synthesis conditions for growing relatively large crystals of AlLB14 (L=Li or Na or K) from LiF or NaF or KF and B powders as the starting materials using high-temperature Al melt. There are few reported examples for syntheses of AlLB14 using alkali fluoride and boron in the same melt. The metal fluorides of LiF or NaF and KF were more suitable as the source of Li or Na or K elements than Li or Na or K metals that had high vapor pressure,13) because of relatively good solubility in the Al melts at high temperature. The morphology and crystallographic data of the AlLB14 (L=Li or Na) crystals obtained were determined. In addition, micro-Vickers hardness at room temperature, electrical resistivity and oxidation resistance by heating of the as-grown crystals were investigated. Furthermore, some properties of the AlLB14 crystals obtained in this study were compared with the previously reported results. Fig. 1 shows the crystal structure of AlLB14. The structure of AlLB14 compound is made up of four B12 icosahedron units and eight single boron atoms per unit cell. The L and Al atoms are accommodated in the largest and smaller holes outside the B12 icosahedral units.8) 2. Experimental Details2.1 Preparation of AlLB14 crystals The reagents used to prepare the AlLB14 compounds were LiF or NaF or KF (purity 99~99.9%, Wako Pure Chemical Industries Ltd. Mitsuwa Pure Chemical Co. Japan), and crystalline boron (purity 99%, Mitsuwa Pure Chemical Co. Japan) powders and Al (purity 99.99%, Nippon Light Metal Co. Japan) metal buttons. The reagents and B were weighted at atomic ratios n=B/L=2.0~4.0. Al metal were added to each mixture at mass ratio 1:15~20. The quantity of alkaline fluorides in the starting material was fixed at 1.5 g throughout all experiments. The reaction equation (1) for obtaining AlLB14 from alkaline fluorides and B powders were as follows.3LF + (3n + 1)B → 3LBn + BF3 -------------(1) The mixture was placed in a dense alumina crucible (Nikkato Co. SSA-H). The crucible was inserted in a vertical electric furnace with a SiC heater and then heated under an argon gas. The mixture was heated at a rate of 300 K·h-1, raised to 1573~1773 K, kept for 5 h and then cooled to room temperature at a rate of 50 K·h-1. The crystals were removed from the solidified melt by dissolving the matrix with dilute hydrochloric acid. The crystals obtained as described above were dried in a dryer. After drying, the resulting crystals were selected with a stereomicroscope.2.2 X-ray and chemical analyses of AlLB14 crystals The crystal structure and lattice constants of the compounds were examined by the powder X-ray diffraction (XRD) (Rigaku, Ultima Ⅲ) with monochromatic CuKα radiation.14) The values of lattice constants were used as the internal standard with high-purity Si (purity 99.99%, High-Purity Chemical Co.). The morphology, size, chemical composition and impurity content of the crystals were observed by a stereomicroscope, the scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX) (Horiba Co. EMAX-2770) and electron probe microanalysis (EPMA) (JEOL, JXA-8621MX).15) 2.3 Properties2.3.1 Determination of micro-Vickers hardness, electrical resistivity, and oxidation resistivity heated in airAs-grown AlLB14 crystals were measured using the micro-Vickers hardness in air. The hardness of the crystal was determined from the average value at room temperature with the load of 1.96 or 2.94 N and a load time of 15 s using about 8 to 12 positions on a well-developed face of each crystal. The values of electrical resistivity were measured by the direct-current four-probe technique at room temperature in air atmosphere. For hardness and electrical resistance measurement, the crystals were embedded in the resin, polished, and then measured. The electrical resistance was measured using KEITHLEY as the power supply and ESSTECH (ESS Tech Co.) as the small prober system. The crystals were powdered in an Al2O3 mortar and then heated to 1473 K in air using the differential thermal analyses and thermogravimetric (DTA-TG, Seiko Instrument) apparatus for oxidation resistance. After inserting the sample into the quartz cell, it was heated in air at a constant rate of 10 K·min-1. The oxidation products were analyzed by powder XRD measurements. 3. Results and Discussion3.1 Syntheses of AlLB14 crystalsAlLB14 crystals could be grown under the conditions using LiF or NaF or KF and boron powders as starting materials by high temperature Al metal. Here, AlLB14 was performed based on experimental conditions obtained from L2B4O7 (L=Li or Na) and B powders. AlLB14 crystals could be grown under the conditions of the atomic ratios n=B/L=2.0~4.0 from LiF or NaF and B powders as starting materials (Table Ⅰ). However, while synthesis of AlKB14 was attempted by utilizing KF and boron powders, AlKB14 was not obtained in the Al-K-B system as shown in Fig. 2. In this case, mixed crystals of grayish black α-AlB12 (tetragonal, space group P41212 or P43212)16,17) and amber color β-AlB12-type18,19) were formed. It can be inferred that the cause of this is that potassium and boron atoms do not react in the high temperature Al melt. Alternatively, it can be inferred that the AlKB14 phase was not formed because the K atom has a larger atomic radius (2.31 Å) or ionic radius (+1) Corresponding Number (CN) (6) 1.52 Å20) than the Li or Na atoms. The XRD patterns of AlLiB14 and AlNaB14 were shown in Fig. 3. From this, AlLB14 phase and alumina were identified. Al2O3 phase is thought to be a contamination derived from the alumina crucible used for crystal synthesis and the alumina mortar used for XRD measurements. AlLB14 crystals could be grown under the conditions of the atomic ratios n=B/L=2.0~4.0. AlLB14 crystals having the typical crystal form are shown in Fig. 4. AlLiB14 and AlNaB14 crystals were obtained as plate-like shape with the pink-grey color. In addition, the lattice constant value of AlNaB14 is related to the size of the atomic radius (for Li, 1.52 Å; for Na, 1.86 Å) or ionic radius (for Li, (+1) CN (6) 0.76 Å; for Na, (+1) CN (6) 1.02 Å13,20) of the metal in the crystal structure, and it can be inferred that it is larger than that of AlLiB14 and AlNaB14. 3.2 Lattice constants and chemical analysis Table Ⅱ shows the lattice constant values of AlLB14. From this, it can be seen that the lattice constant of AlNaB14 is slightly higher than that of AlLiB14. As described in Section 3.1, it can be inferred that this is a difference in the size of metal atoms or metal ions contained in the AlLB14 compound. In addition, the lattice constants of AlLB14 are very similar to those reported synthesized from different starting materials; AlLiB14 (for example, AlLiB14 obtained from Li2B4O7; a=5.847(1), b=10.354(1), c=8.143(1) Å, V=493.0(1) Å3,7) AlLiB14 obtained from metal Li; a=5.8469(9), b=10.3542(6), c=8.1429(8) Å, V=492.97(9) Å3,2) and AlNaB14 obtained from Na2B4O7; a=5.844(1), b=10.465(1), c=8.231(1) Å, V=503.4(1) Å3.8) Chemical analysis for the AlNaB14 crystal corresponds to atomic ratio Al:L:B=1:1:14 (see Table Ⅲ). However, chemical analysis of AlLiB14 has not been performed. The chemical analysis value of AlNaB14 crystals seems to have fewer Na and Al atoms than the atomic ratio Al:Na:B=1:1:14 of stoichiometry ratio. The values of the chemical analysis of AlNaB14 obtained from Na2B4O7 and boron in Al metal reported earlier are consistent with the stoichiometric ratio of the atomic ratio Al:Na:B=1.00:0.95:14.8) According to the results of this experiment, the chemical analysis value of AlNaB14 crystal seems to have slightly fewer Na and Al atoms than the atomic ratio Al:Na:B=1:1:14 in the stoichiometric ratio. As a result, it can be inferred that the change in the composition ratio of the AlNaB14 crystal is the difference of Na2B4O7 or NaF in the starting materials.3.3 Properties 3.3.1 Measurement of micro-hardness and oxidation resistance by heating in airTable IV shows the micro-Vickers hardness values of AlLiB14 and AlNaB14 crystals together with the values of AlLB14 reported by the authors. From them AlLiB14 and AlNaB14 are approximately the same hardness value. The values of the crystals are in comparatively good agreement with the values of these faces for AlLiB14 and AlNaB14 in the literature.2,7,9) Higher borides containing B12 icosahedron unit have been reported to have relatively high hardness. For instance, B6O (Hv=34~38 GPa), B4C (Hv=34.5~40 GPa), cBN (Hv=50~60 GPa),21) and Al1.1Be0.7B22, Al1.4Mg0.45B22, AlxCuyB105 (x=2.8~3.3, y=2.9~1.0) and Al1.3Cu1.1B25 (Hv=25.4(±0.5)~27.8(±1.7) GPa) crystals.22,23) However, the authors report on the hardness of TmAlB4 and YbAlB4 with YCrB4-type compounds and the novel solid solution Tm(Al,Mo)B4 and Yb(Al,T)B4 (T=Cr, Fe, Mn, Mo). These hardness values were 14.5(±1.4) GPa for TmAlB4, 13.0(±1.5)~15.5(±2.4) GPa for Tm(Alx-1Mox)B4 (x=0~0.01), 14.2(±1.4) GPa for YbAlB4 and 13.0(±0.6)~16.8(±1.5) GPa for Yb(Al1-xTx)B4 (x=0~0.1; T=Fe, Cr, Mn).15,24~26) It can be seen that the hardness of AlLB14 crystals is higher than that of YCrB4-type compounds. The crystal structure of YCrB4-type is similar to that of AlB2-type, but YCrB4-type is layered in the c-plane direction by the 5-membered and 7-membered rings of boron atoms (the structure of AlB2 is the 6-membered ring of boron atoms).4) It can be inferred that this is due to the difference between these structures and the crystal structure of AlLB14. AlLB14 crystals have the same values in the hardness of higher borides that have B12 icosahedral unit in the crystal. The oxidation process of AlLiB14 and AlNaB14 crystals were studied at temperatures below 1473 K by DTA-TG analyses in air atmosphere. Oxidation of the AlLiB14 crystals were starts at about 805 K (see Fig. 5). From the TG curve, the oxidation initiation temperature was about 815 K for AlLiB14 and 814 K for AlNaB14. The final oxidation products, as analyzed by powder XRD, were Li2B2O4, Al4B2O9, B2O3 and amorphous phases, and so the exothermic peaks (for AlLiB14 about 960 K; for AlNaB14 about 990 K) are attributed to oxidation products.3.3.2 Electrical resistivityThe results for measured resistance (Ω) and the electrical resistivity values (Ω·cm) of AlLiB14 and AlNaB14 crystals are shown in Table Ⅴ. Comparing these results with the electrical resistivity of higher boride and metal borides, it is as follows: B12P2 (p-type) 5.2×104 Ω·cm, B12P2 (p-type) 9.0×104 Ω·cm;27) B4C 1.0 Ω·cm;28) B4C 0.1~10 Ω·cm;29) hBN 1.7×1013 Ω·cm, cBN 1×1016 Ω·cm, ScB2 13×10-6 Ω·cm, TiB2 5.7×10-6 Ω·cm, VB2 38×10-6 Ω·cm, YB2 39×10-6 Ω·cm, TaB2 14×10-6 Ω·cm;29) DyB12 25.56×10-6 Ω·cm, HoB12 13.18×10-6 Ω·cm, ErB12 12.40×10-6 Ω·cm, TmB12 14.04×10-6 Ω·cm, LuB12 11.5×10-6 Ω·cm;29) LuAlB4 86(±6)×10-6 Ω·cm, Lu2AlB6 31(±3)×10-6 Ω·cm;30) PrRh4.8B2 670×10-6 Ω·cm.31) From this result, it can be understood that the electrical resistivity values of AlLB14 crystals were relatively close to the value of B4C with B12 icosahedral units. Namely, the electrical resistivity of the AlLB14 compounds were close to that of the semiconductor region, in contrast to the insulating RB66 (R=rare earth) compounds which also have B12 icosahedral units. AlLB14 has a structure similar to that of NaBB14 (NaB15 orthorhombic, space group Cmcm),31) and the basic structural units of the NaBB14 structure are the B12 icosahedron units and the boron atoms. In NaBB14, free boron atoms are stored at the site corresponding to the Al site in AlNaB14. Although this structure is close to the structure of AlLB14, there are few reported examples of various physical properties due to the difficulty of synthesis. In addition, B4C (rhombohedron, space group R-3m) is classified as β-rhombohedral boron,21) but the structure of B4C is located at the midpoint of the lattice point and the ridge of the B12 icosahedral lattice, and there are two B28 units on the diagonal of the rhombohedral lattice. There is a single boron atom between the two units. It was found that B4C having such the structure has an electrical resistivity close to that of AlLB14.4. ConclusionsAlLB14 (L=Li or Na or K) crystals were grown using LiF or NaF or KF and crystalline boron powders as the starting materials using a high-temperature Al melt at soaking temperature 1573~1773 K for soaking time 5 h in an Ar atmosphere. Mixtures of these materials in various atomic ratios (n=B/L=2.0~4.0). The results are as follows.1) AlKB14 crystal is not obtained from KF and B powders. In that case, α-AlB12 and β-AlB12-type crystals are obtained.2) AlLiB14 and a new compound AlNaB14 crystals obtained have the plate-like shape. The lattice constant values of the obtained AlLB14 compounds were in good agreement with the previously reported values of AlLB14 obtained from L2B4O7 or lithium metal and B powders as starting materials.3) The results of micro-Vickers hardness measurements of as-grown AlLB14 crystals are discussed. In particular, the hardness values of AlLiB14 and AlNaB14 were equivalent to the higher borides with B12 icosahedral units of Al1.1Be0.7B22, Al1.4Mg0.45B22, Al1.3Cu1.1B25 and AlxCuyB105 (x=2.8~3.3, y=2.9~1.0) crystals. 4) The oxidation resistance in air up to 1473 K of as-grown AlLiB14 and AlNaB14 crystals were investigated. 5) The electrical resistivity of the AlLB14 compound are the values of 146~157 Ω·cm for AlLiB14 and 2.4~57 Ω·cm for AlNaB14. These values for the electrical resistivity of AlLB14 are in the semiconductor region.AcknowledgmentsThe authors are indebted to IMR in Tohoku University for their technical contributions and Ms. Yoko Imai of Kanagawa University for their help in the experiments. 1) I. Higashi, M. Kobayashi, Y. Takahashi, S. Okada and K. Hamano: J. Cryst. Growth 99 (1990) 998. 2) I. Higashi, M. Kobayashi, S. Okada, K. Hamano and T. Lundström: J. Cryst. Growth 128 (1993) 1113.3) S. Okada, K. Kudou, T. Mori, T. Shishido, I. Higashi, N. Kamegashira, K. Nakajima and T. Lundström: Materials Science Forum 449-452 (2004) 365. 4) V. I. Matkovich (Ed.): Boron and Refractory Borides, Springer-Verlag, 1977, p.439.5) I. Higashi and Y. Takahashi: J. Less-Common Met. 81 (1981) 133.6) I. Higashi: J. Less-Common Met. 82 (1981) 317.7) K. Kudou, S. Okada, T. Mori, K. Iizumi, T. Shishido, T. Tanaka, I. Higashi and K. Nakajima, P. Rogl, Y. B. Andersson and T. Lundström: Jpn. J. Appl. Phys. 41 (2002) L928.8) S. Okada, T. Tanaka, A. Sato, T. Shishido, K. Kudou, K. Nakajima and T. Lundström: J. Alloys compd. 395 (2005) 231.9) S. Okada, T. Mori, K. Kudou, T. Tanaka, T. Shishido and T. Lundström: J. Euro. Ceram. Soc. 26 (2006) 631.10) S. Okada, K. Kudou, T. Shishido, K. Yubuta and T. Mori: J. Solid State Phenomena 170 (2011) 150.11) S. Okada, T. Shishido, T. Mori, K. Iizumi, K. Kudou and K. Nakajima: J. Alloys Compd. 458 (2008) 297.12) S. Okada, K. Kouzu, T. Yamasaki, T. Mori, K. Yubuta, A. Nomura, T. Shishido, A. Yoshikawa and P. Rogl: J. Flux Growth 13 No.1, (2018) 9 [in Japanese].13) David R. Lide Editor-in-Chief, Howard T. Evans, Jr: CRC Handbook of Chemistry and Physics 1995-1996, 76th Edition, CRC press, New York, p.12-14.14) K. Kouzu, S. Okada, K. Hagiwara, A. Nomura, T. Shishido, A. Yoshikawa, K. Yubuta, C. Bourgés and T. Mori: J. Jpn. Soc. Powder Powder Metallurgy 70 (2023) 461 [in Japanese].15) K. Kouzu, T. Yamasaki, S. Okada, T. Mori, Q. Quo, K. Yubuta, A. Nomura, T. Shishido, A. Yoshikawa and P. Rogl: J. Jpn. Soc. Powder Powder Metallurgy 66 (2019) 525.16) I. Higashi and T. Ito: J. Less-Common Met. 92 (1983) 239.17) I. Higashi: J. Solid State Chem. 154 (2000) 168.18) J. A. Kohn and D. W. Eckart: Anal. Chem. 32 (1960) 296.19) S. Okada and T. Atoda: Yogyo Kyokai-shi 88 (1980) 547 [in Japanese].20) K. Niwa el al.: The ceramic Society Japan, Handbook of Ceramics 2nd Edition, Gihodo Shuppan Co. (2002) p.683.21) K. Takagi, R. Uno, K. Kimura, I. Higashi, T. Tanaka, T. Shishido, T. Mori, Y. Ishizawa, S. Okada et al.: Fundamentals and Application of Boron, Borides and Related Materials, CMC (2008) p.3.22) S. Okada, T. Mori, T. Shishido, K. Iizumi, K. Kudou, K. Nakajima and P. Rogl: J. Alloys Compd. 442 (2007) 320.23) S. Okada: J. Technical Association of Refractories, Japan 32 [4] 239 (2012) [in Japanese].24) S. Okada, K. Kudou, Y. Yu, T. Lundström: Jpn. J. Appl. Phys. 33 No.5A (1994) 2663.25) S. Okada, K. Kouzu, T. Yamasaki, T. Mori, Q. Guo, T. Shiashido, K. Yubuta, G. Rogl and P. Rogl: Solid State Phenomena 289 (2019) 65.26) S. Okada, K. Kudou, Y. Yu and T. Lundström: Pro. 11th Int. Symposium on Boron, Borides and Related Compounds, Tsukuba 1993 JJAP Series 10, (1994) 136.27) Y. Kumashiro, H. Yoshizawa and K. Shirai: Jpn. J. Appl. Phys. 10 (1994) 166.28) G. V. Samsonov and I. M. Vinitskii: Handbook of Refractory Compounds, IFI/Plenum, New York, 1980, p. 233.29) Y. Paderno, V. Filippov and N. S. Shitsevalova: Pro. 11th Int. Symp. Boron, Borides and Related Compounds, Tsukuba 1993 JJAP Series 10 (1994) 154.30) S. Okada, Y. Yu, T. Lundström, K. Kudou and T. Tanaka: Jpn, J. Appl. Phys. 35 (1996) 4718.31) S. Okada, T. Shishido, K. Kudou, I. Higashi, M. Ogawa, H. Horiuchi and T. Fukuda: J. Ceram. Soc. Japan 107 (1999) 184.32) R. Naslain, A. Guette and P. Hagenmuller: J. Less-Common Met. 47 (1976) 1.Table Ⅰ. Synthesis conditions of AlLB14 compounds obtained from LF and B powders as starting materials at soaking temperature 1573~1773 K for soaking time 5 h. 　 B/L Soaking temperature 　 Alkali fluorides (atomic ratios) (K) Phases identified LiF 2.0, 4.0, 6.0 1573, 1673, 1773 AlLiB14 NaF 2.0, 4.0, 6.0 1573, 1673, 1773 AlNaB14 KF 2.0, 4.0, 6.0 1573, 1673, 1773 α-AlB12, β-AlB12-type Table Ⅱ. The results for lattice constants of AlLB14 compounds. Compounds ― Lattice constants (Å) AlLB14 Alkalifluorides a b c V (Å3) AlLiB14 LiF 5.850(1) 10.359(1) 8.145(1) 493.6(1) AlNaB14 NaF 5.851(2) 10.455(4) 8.243(3) 504.2(3)Table Ⅲ. The results for chemical analysis of AlNaB14. Compound Crystal Chemical analysis(mass%) In total Chemicalcomposition Al Na B AlNaB14 Plate 5.55 4.96 89.49 100 Al0.87Na0.78B14Table Ⅳ. The values for micro-Vickers hardness of AlLB14 crystals. Compounds Micro-hardness values Reference AlLB14 metal salts or metal (GPa) AlLiB14 LiF 24(±1) this work ˶ Li 25(±1)~29(±1) 2) ˶ Li2B4O7 20(±1)~29(±1) 7) AlNaB14 NaF 25(±1) this work ˶ Na2B4O7 23(±1)~28(±1) 9)Table Ⅴ. Results of resistance (Ω) and electrical resistivity (Ω·cm) of AlLiB14 and AlNaB14 crystals. Compounds resistance (Ω) Electrical resistivity /ρ (Ω・cm) AlLiB14 64~594 146~157 AlNaB14 17~399 2.4~57Figure captionsFig. 1 Crystal structure of AlLB14 compound: a-plane perspective and three-dimensional perspective6) view.Large boron lump: B12 icosahedron unit. large circle: L (Li or Na), middle circle: Al, small circle: BFig. 2 XRD patterns of AlLB14 (L= Li or Na) obtained from LiF or NaF and B powders as starting materials and Mg0.78Al0.75B14 (ICDD Card No.39-0459). Fig. 3 Photographs for stereoscopic microscopy of AlLiB14 (A) and AlNaB14 (B) crystals obtained by LiF or NaF and B powders as the starting materials. (C) α-AlB12 and (D) β-AlB12-type crystals obtained from KF and B powders as the raw materials. Soaking temperature; 1673 K, Soaking time; 5 hFig. 4 DTA-TG analyses of (a) AlLiB14 and (b) AlNaB14 crystals heated in air. Sample was heated in air at a constant rate of 10 K·min-1.　　　　a-plane perspective　　　　 three-dimensional perspective6)Fig. 1 Crystal structure of AlLB14 compound: a-plane perspective and three-dimensional perspective6) view.Large boron lump: B12 icosahedron unit, large circle: L (Li or Na), middle circle: Al, small circle: BICDD CardNo.39-0459Fig. 2 XRD patterns of AlLB14 (L= Li or Na) obtained from LiF or NaF and B powders as starting materials and Mg0.78Al0.75B14 (ICDD Card No.39-0459). 　(A) AlLiB14 crystals (B) AlNaB14 crystals(C) α-AlB12 crystals (D) β-AlB12-type crystalsFig. 3 Photographs for stereoscopic microscopy of AlLiB14 (A) and AlNaB14 (B) crystals obtained by LiF or NaF and B powders as the starting materials. (C) α-AlB12 and (D) β-AlB12-type crystals obtained from KF and B powders as the raw materials. Soaking temperature; 1673 K, Soaking time; 5 hDTA curveTG curve(a) DTA-TG curve of AlLiB14 TG curveDTA curve(b) DTA-TG curve of AlNaB14 Fig. 4 DTA-TG analyses of (a) AlLiB14 and (b) AlNaB14 crystals heated in air. Sample was heated in air at a constant rate of 10 K·min-1.image2.pngimage3.svg L (Na or Mg) Al B B icosahedron unitimage4.pngimage5.svg Intensity ［ a. u. ］ 2 θ ［ ° ］（Cu - K α ） AlNaB 14 AlLiB 14 ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ： Al 2 O 3image6.jpegimage7.emf0.5 mmimage8.jpegimage9.jpegimage10.emf-2000-1500-1000-50005001000020406080100500 750 1000 1250 1500Heat Flow ( μV/mol )Temperature ( K )Weight increase rate ( % )image11.emf-800-600-400-2000200400600800020406080100500 750 1000 1250 1500Temperature ( K )Heat Flow ( μV/mol )Weight increase rate ( % )image1.png