Stabilization of a Tetrahedral (Mn5+O4) Chromophore in Ternary Barium Oxides as a Strategy toward Development of New Turquoise/Green-Colored Pigments

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• 作者：Sourav Laha ; Subramani Tamilarasan ; Srinivasan Natarajan ; Jagannatha Gopalakrishnan
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：April 4, 2016
• 年：2016
• 卷：55
• 期：7
• 页码：3508-3514
• 全文大小：574K
• ISSN：1520-510X

文摘

An experimental investigation of the stabilization of the turquoise-colored chromophore Mn⁵⁺O₄ in various oxide hosts, viz., A₃(VO₄)₂ (A = Ba, Sr, Ca), YVO₄, and Ba₂MO₄ (M = Ti, Si), has been carried out. The results reveal that substitution of Mn⁵⁺O₄ occurs in Ba₃(VO₄)₂ forming the entire solid solution series Ba₃(V_1–xMn_xO₄)₂ (0 < x ≤ 1.0), while with the corresponding strontium derivative, only up to about 10% of Mn⁵⁺O₄ substitution is possible. Ca₃(VO₄)₂ and YVO₄ do not stabilize Mn⁵⁺O₄ at all. With Ba₂MO₄ (M = Ti, Si), we could prepare only partially substituted materials, Ba₂M_1–xMn⁵⁺_xO_4+x/2 for x up to 0.15, that are turquoise-colored. We rationalize the results that a large stabilization of the O 2p-valence band states occurs in the presence of the electropositive barium that renders the Mn⁵⁺ oxidation state accessible in oxoanion compounds containing PO₄^3–, VO₄^3–, etc. By way of proof-of-concept, we synthesized new turquoise-colored Mn⁵⁺O₄ materials, Ba₅(BO₃)(MnO₄)₂Cl and Ba₅(BO₃)(PO₄)(MnO₄)Cl, based on the apatite—Ba₅(PO₄)₃Cl—structure.