An investigation into some important properties of transition metals (densities, resistivities, coefficients of expansion and enthalpies of formation of M x+ ions)

Applying the soft sphere model to improve the understanding of bonding in transition metals

“…The "ions in a sea of electrons" model was developed some time ago when there was much less experimental data available. From previous work [6,10,11,12] it is evident that the ions in a sea of electrons model or any similar model of metallic bonding cannot clarify many of the properties of the transition metals nor can any equations be derived from it which can replicate values such as enthalpies of formation (atomisation), densities, heat capacities, electrical resistivities etc. The soft/flexible sphere model can be used to explain many metallic properties.…”

“…However these electrons are not "free" or completely delocalized but can move within the midpoint positions between ions in a unit cell. Transition metal properties are well known [13] and a more detailed description of and how the model can account for various properties of metals can be found in prior work [6,12] and not repeated here.…”

“…Different transition metals have different electron configurations and so the number of detached electrons is liable to be different for different elements. As has already been described previously [12] Table 1 lists the number of detached electrons per atom for the transition metals which affects the bonding in the individual metal solids. In some instances, the maximum number of detached electrons may not be reached because of the many defects in the solid state.…”

“…Recently published work [6] has provided overwhelming evidence that the "electron sea" model is a misleading and poor representation of metallic bonding. The aim of this work is to apply the soft sphere model [7,8,9] to help further improve understanding of bonding in transition metals in addition to the results of previous work already published [10,11,12].…”

Is a Metal “Ions in a Sea of Delocalized Electrons?”

“…For example, a metal with the bcc structure has only eight nearest neighbors, and therefore, each atom in the unit cell can have a maximum of only four detached electrons and a minimum of one detached electron (or half an electron in the case that only one of the two atoms has an electron detached and occupying a midpoint site). As already mentioned in earlier work, the model also assumes that only a very small proportion of electrons in any atom take part in current flow when a potential difference exists across the metal solid, or else numerous “free” electrons will collide with each other, releasing energy in the process and causing the temperature of the solid to increase rapidly. Some further details of the model are given in previous work. , …”