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The research team led by Professor Zou Bo, the State Key Laboratory of Superhard Materials of Jilin University, made a breakthrough in the research of negative compression materials. The researchers found that the metal-organic framework material InH(BDC)2 is one of the materials with the largest negative compression ratio known so far, and is safer and cheaper than traditional large negative compression ratio materials. The result was titled "Large Negative Linear Compressibility in InH (BDC) 2 from Framework Hinging" and was published on October 25, 2017 in the American Chemical Society. Conventional materials will be compressed in all directions of the crystal under the action of increasing hydrostatic pressure, and the negatively compressed material will elongate in a certain direction with increasing pressure, that is, pressure-induced expansion. The singular characteristics of this pressure-induced expansion make the negative compression material extremely important potential application in many fields such as high-sensitivity sensors, submarine cables and artificial intelligent prostheses. Compared to positive compression, the number of known negative compression materials is currently very small and the absolute value of negative compression is relatively small (usually below −20 TPa-1), which greatly limits the practical application of such materials. Finding materials with large negative compressibility has become a hot topic in the fields of physics, chemistry and materials. In this paper, the researchers used indium hydrogen isophthalate (InH(BDC)2) as the research object, and determined by high-pressure in-situ synchrotron radiation X-ray diffraction technology: the material extends along the crystal axis in the range of 0 to 0.53 GPa. The material has a negative c-axis compression ratio of −62.4 TPa-1, which is the material with the largest negative compression ratio except silver cobalt cyanide (negative compression ratio −76 TPa-1). Because it does not contain highly toxic cyano groups and high precious metal components, indium hydrogen phthalate is safer and cheaper than cobalt cobalt cyanide, and silver cobalt cyanide occurs at very low pressure (0.19 GPa). The phase change is accompanied by a volume collapse of 16.25%, so that indium hydrogen phthalate has a higher application value than silver cobalt cyanate. Synchrotron radiation X-ray diffraction data indicates that the negative compressibility of indium hydrogen isophthalate is due to the six-membered ring-β quartz structure composed of its special metal-organic chain. This particular crystal geometry contains two important parameters: the organic chain length r and the angle θ between the chains. When the pressure is increased, r is substantially constant and θ is gradually decreased, so that the projection of r becomes longer in the c-axis direction and shortens in the ab-axis direction, that is, the crystal is elongated along the ab axis and elongated along the c-axis when the pressure is increased. In combination with the previously reported large negative compressive material zinc citrate, a researcher believes that more materials with greater negative compressibility can be found in the metal-organic framework materials of the beta quartz structure. The research team led by Professor Zou Bo has long been engaged in the research of negative compression materials. Previously, a new mechanism of negative compression, layer slip, was proposed through the study of cobalt thiocyanate. “Negative Linear Compressibility Due To Layer Sliding in a Layered Metal−Organic Frameworkâ€, published in the Physical Chemistry Letters. The research was supported by the National Natural Science Foundation of China, the National Science Fund for Distinguished Young Scholars, the Education Minister Jiang Scholars Award Program, and the Jilin Province Changbai Mountain Scholars Award Program. The first author of the thesis is Zeng Qingxin, a doctoral student at the State Key Laboratory of Superhard Materials.