Scientists have endeavored to explain chemical bond in order to delineate the force between atoms in molecules. The theory, however, is highly complicated and who frequently modified. One important concept that is universally true is that the more bonds between two atoms, the closer the two atoms are to each other and thus the greater force between them. In the forty years before 2005, metal-metal quadruple bond complex is as far as scientists could synthesize. After the physics and chemistry of quadruple-bond complex is fully understood, scientists began to turn to synthesizing complexes with more bonds. During this time, some have discovered metal-metal sextuple bonds under low temperature and pressure using spectrums. From synthetic point of view, synthesis of sextuple bonded metal-metal complexes is rather impractical. Scientists thus have instead placed their hopes on synthesizing quintuple bonded metal-metal complexes. A breakthrough came three years ago in synthesizing a quintuple bonded metal-metal compound, and suddenly it has emerged as a hot research subject and a new field.

As metal-metal quintuple bonds could lead to a more comprehensive understanding of the force between atoms, it has been one of the focuses in the fields of theoretical chemistry and inorganic chemistry in the past decades. It is remarkable that Tsing Hua chemistry professor Yi-Chou Tsai's research team has synthesized two types and a total of five quintuple-bonded dichromium complexes. More importantly their synthesized complexes of 1.74 angstrom (1 angstrom =10^-10 m) broke the world record of the shortest metal-metal distance. Tsai's team has recently published a correspondent paper in Germany's leading journal Angewandte Chemie. Due to its significance in the field and its publication during the Beijing Olympics, the research result was featured as a cover story in the American Science and British Nature and Nature Chimistry journals under the title, "Yi-Chou Tsai Wins the Olympic Gold Medal in The Global Race to Find The Shortest Metal-Metal Bond in Chemistry."