Synthesis, Structure, and Properties of Two Zintl Phases around the Composition SrLiAs

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• 作者：Xian-Juan Feng ; Yurii Prots ; Marcus Peter Schmidt ; Stefan Hoffmann ; Igor Veremchuk ; Walter Schnelle ; Ulrich Burkhardt ; Jing-Tai Zhao ; Yuri Grin
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：August 5, 2013
• 年：2013
• 卷：52
• 期：15
• 页码：8971-8978
• 全文大小：508K
• 年卷期：v.52,no.15(August 5, 2013)
• ISSN：1520-510X

文摘

Two atomic arrangements were found near the equiatomic composition in the strontium鈥搇ithium鈥揳rsenic system. Orthorhombic o-SrLiAs was synthesized by reaction of elemental components at 950 掳C, followed by annealing at 800 掳C and subsequent quenching in water. The hexagonal modification h-SrLi_1鈥?i>xAs was obtained from annealing of o-SrLiAs at 550 掳C in dynamic vacuum. The structures of both phases were determined by single-crystal X-ray diffraction: o-SrLiAs, structure type TiNiSi, space group Pnma, Pearson symbol oP12, a = 7.6458(2) 脜, b = 4.5158(1) 脜, c = 8.0403(3) 脜, V = 277.61(2) 脜³, R_F = 0.028 for 558 reflections; h-SrLi_1鈥?i>xAs, structure type ZrBeSi, space group P6₃/mmc, Pearson symbol hP6, a = 4.49277(9) 脜, c = 8.0970(3) 脜, V = 141.54(1) 脜³, R_F = 0.026 for 113 reflections. The analysis of the electron density within the framework of the quantum theory of atoms in molecules revealed a charge transfer according to the Sr^1.3+Li^0.8+As^{2.1鈥?/sup>, in agreement with the electronegativities of the individual elements. The electron localizability indicator distribution indicated the formation of a 3D anionic framework [LiAs] in o-SrLiAs and a rather 2D anionic framework [LiAs] in h-SrLi_1鈥?i>xAs. Magnetic susceptibility measurements point to a diamagnetic character of both phases, which verifies the calculated electronic density of states.}