Niobium(V) oxalate is the hydrogen oxalate salt of niobium(V). The neutral salt has not been prepared.[2]
Complexes
Niobium(V) can form complexes with hydroxy acids, as well as oxalic acid. The salt formed is more complex than tartaric acid for niobium (as opposed to tantalum).[3] NH4[NbO(C2O4)2(H2O)2]·3H2O starts to lose water at 125°C, and at 630°C, it fully decomposes, forming a compound known as niobium pentoxide;[4] Heating this complex and sodium citrate at 650°C can form sodium niobate (NaNbO3).[5]
Rb3[NbO(C2O4)3]·2H2O is a colourless crystal, which includes the [NbO(C2O4)3]3- anion.[6] Sr3[NbO(C2O4)3]2·8H2O is a compound containing the same anion, forming the anhydrous at 200°C, starting to decompose at 260°C, and at 875°C it decomposes to SrCO3 and SrNb2O6.[7]
References
^John A Dean. Lange's Handbook of Chemistry, 11th ed. McGraw-Hill Book Company, 1973. pp 4-87
^A Textbook of Inorganic Chemistry. Vol VI, Part III. Vanadium, Niobium and Tantalum. Charles Griffin & Company Ltd, 1929. pp 166. Oxalo-niobic Acid.
^Shen, Panwen; et al. Series of Inorganic Chemistry. Vol 8. Titanium group, vanadium group, chromium group. Science Press, 2011. pp 279-280.
^Xu, Xiaoshu; Su, Tingting; Jiang, Heng. Study on thermal decomposition process of niobium oxalate. Fenxi Yiqi, 2009. (5): 75-77.
^Bian, Yu-bo; Jiang, Heng; Su, Ting-ting; Gong, Hong. 柠檬酸钠与草酸铌合成NaNbO3粉体的反应机理 (lit. Study on the synthesis mechanism of NaNbO3 powder from sodium citrate and niobium oxalate). Huaxue Gongchengshi (Chemical Engineer), 2011 (3): 56-58
^Šestan, M., Perić, B., Giester, G. et al. Another Structure Type of Oxotris(oxalato)niobate(V): Molecular and Crystal Structure of Rb3[NbO(C2O4)3]⋅2H2O. Struct Chem (2005) 16: 409. doi:10.1007/s11224-005-3111-7
^Marta, L., Zaharescu, M. & Macarovici, C.G. Thermal and structural investigation of some oxalato-niobium complexes. Journal of Thermal Analysis (1983) 26: 87. doi:10.1007/BF01914092
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