Preparation Of Croconic Acid Single Crystals And Studying Its Dielectric Properties

In recent years, with more and more rapidly development of all kinds of newtechnology in field of microelectronics, micro-computer technology and IT, therequirement of memory performance is increasingly higher and higher, especially inthe aerospace field. The ferroelectric memory has excellent resistance to radiation,superior performance of fast reading and writing capability, low operating voltage.So it is considered to be the most potential products in the field of memories.Croconic Acid （4,5-dihydroxy-4-cyclopentene-1,2,3-trione） was preparedfrom the raw material of C₆Cl₄O₂（tetrachoro-1,4-benzoquinone） through theintermediates of C₁₀H₁₂O₆（tetramethoxy-1,4-benzoquinone） and C₆H₄O₆（tetrahydroxy-1,4-benzoquinone）. The products of every step and byproducts werecharacterized by IR, H-NMR, MS. And the preparing techniques of C₁₀H₁₂O₆andC₆H₄O₆were discussed. The result showed the maximum productivity of CroconicAcid was27.5%under the optimum conditions.Used Croconic Acid prepared as raw material, Croconic Acid single crystalwas grown by the method of evaporating solvent. The influencing factors, such asPH, in the process of growing single crystal were studied. At last, the ideal CroconicAcid single crystal was gained from1mol/L HCl solution. The single crystalstructure of Croconic acid was analyzed by X-ray single crystal diffractometer. Theresult showed: the Croconic Acid single crystal belongs to orthorhombic, pointgroup mm², crystal parameter a=8.7038（4）, b=5.1695（2）, c=10.9622（4）, Z=4.Croconic Acid single crystal is a kind of order ferroelectrics. The properties ofCroconic Acid single crystal, such as εr-T, Dielectric loss, ferroelectric hysteresisloops, J-V, were analyzed. The result showed: when E=420V/cm, f=100Hz,Croconic Acid single crystal had a good ferroelectric hysteresis loop withPs=3.54μC/cm², Pr=1.73μC/cm², and Ec=170V/cm. The reason why Croconic Acidsingle crystal had ferroelectricity was analyzed.