Abstract The monoclinic α-polymorph of (VIVO)(PO3)2 is obtained reproducibly by reaction of V2O5 and H3PO4 (85%) (Au crucible, 380 °C, 4 d). Its crystal structure was refined from X-ray single-crystal data [C2/c, Z = 4, a = 15.1038(7) Å, b = 4.193(2) Å, c = 9.573(9) Å, β = 126.45(3), R 1 = 0.052, wR 2 = 0.189 for 976 unique reflections with F o > 4σ(F o ), 48 variables]. A single-phase powder of the β-polymorph is obtained by the reaction of V2O5, H3PO4 (85%) and oxalic acid, evaporating the mixture, and subsequent annealing (porcelain crucible, 800 °C in air, 2 d). Single crystals of β-(VIVO)(PO3)2 were grown in a sealed silica ampoule with chlorine as mineralizer. The crystal structure of the orthorhombic (pseudo-tetragonal) β-polymorph was refined from X-ray single-crystal data [pseudo-merohedral twin, Fdd2, Z = 8, a = 15.536(2) Å, b = 15.586(2) Å, c = 4.2611(5) Å, R 1 = 0.032, wR 2 = 0.068 for 1072 unique reflections with F o > 4σ(F o ), 50 variables]. Earlier reports on a tetragonal polymorph with unusual geometric structure of the [(V≡O)O5] polyhedron are corrected.

中文翻译：

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VO(PO3)2 的多晶型：重新审视合成和晶体结构改进

摘要 (VIVO)(PO3)2 的单斜 α-多晶型物可通过 V2O5 和 H3PO4 (85%) 的反应（金坩埚，380 °C，4 天）重复获得。其晶体结构由 X 射线单晶数据 [C2/c, Z = 4, a = 15.1038(7) Å, b = 4.193(2) Å, c = 9.573(9) Å, β = 126.45( 3), R 1 = 0.052, wR 2 = 0.189 对于 976 次独特反射，F o > 4σ(F o )，48 个变量]。通过V2O5、H3PO4（85%）和草酸反应、蒸发混合物和随后的退火（瓷坩埚，800℃空气中，2天）获得β-多晶型物的单相粉末。β-(VIVO)(PO3)2 单晶在密封的硅胶安瓿中生长，氯气作为矿化剂。正交（伪四方）β-多晶型物的晶体结构是根据 X 射线单晶数据 [伪多面体孪晶，Fdd2，Z = 8，a = 15.536(2) Å，b = 15 精炼而成的。586(2) Å, c = 4.2611(5) Å, R 1 = 0.032, wR 2 = 0.068 对于 1072 次独特的反射，F o > 4σ(F o )，50 个变量]。早先关于具有不寻常几何结构的 [(V≡O)O5] 多面体的四方多晶型物的报道已得到纠正。