Abstract Na3B20 powder was prepared by heating amorphous B and Na in a BN crucible at 1173–1373 K. Na2B29, which was formed from Na3B20, was contained in the products obtained at and above 1453 K. Black square plate-like Na3B20 single crystals with a size of approximately 40–100 μm were grown by heating crystalline B and Na at 1223 K for 48 h. Na3B20 was relatively unstable against the moisture in air, and gradually converted into H3BO3. A polycrystalline bulk Na3B20 sample with a relative density of 73.4% was obtained by heating a compact of ball-milled amorphous B powder in Na vapor at 1223 K for 24 h. The electrical conductivity of the bulk sample was 1.15 × 106 S/m at 295 K.

中文翻译：

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Na3B20的合成及导电性

摘要 Na3B20 粉末是通过在 BN 坩埚中在 1173–1373 K 下加热无定形 B 和 Na 制备的。由 Na3B20 形成的 Na2B29 包含在 1453 K 及以上获得的产品中。黑色方形板状 Na3B20 单晶与通过在 1223 K 下加热结晶 B 和 Na 48 小时，生长了大约 40-100 μm 的尺寸。Na3B20 对空气中的水分相对不稳定，逐渐转化为 H3BO3。通过将球磨无定形 B 粉末在 Na 蒸气中以 1223 K 的温度加热 24 小时，获得了相对密度为 73.4% 的多晶块状 Na3B20 样品。大块样品在 295 K 时的电导率为 1.15 × 106 S/m。