The key is long

The average distance between the nucleus of two bonded atoms in a molecule is called bond length. The shorter the key length, the stronger the chemical bond is when the atoms bind more firmly. The key length can be measured by
spectroscopy
method or
X-ray
structural analysis, or by quantum chemical calculation method. Metal atoms of metal crystals form crystals by dense accumulation, analyze and measure their cell parameters by X-ray structure, and then combine their dot matrix form to calculate the distance between the adjacent metal atoms, that is, the length of the metal bonds. There is no single molecule in the ion crystal, and the arrangement of ions is related to the radius ratio of positive and negative ions, so the bond length of the ion bond is regarded as the nuclear spacing when the unequal diameter sphere of positive and negative ions is cut. They also take the method of dense accumulation, the same according to the X-ray structure analysis method to determine its cell type, size, dot matrix form, by calculation. Co-priced crystal atoms are combined with co-priced bonds, and co-priced key length is related to the co-price radius of atoms, but also to the binding method between atoms. The bond length of the same bond type varies slightly
the
of the compound, mainly due to the influence of neighboring atoms or groups.