The Crystalline Constitutive Particles Dimension

In crystal chemistry, particles sizes are represented by ionic and atomic radii. Admission of such size is related to the assumption that the ions and the atoms have spherical shapes and a determined volume, impenetrable to others ions or atoms. Thus, the inter-ionic or inter- atomic distance that is established between two particles in a network, i.e., the distance between the mass centers of these particles is equal to the sum of radius of the two particles. Based on this assumption certain determinations to establish the ionic and atomic radii are therefore possible. However, aiming to determine the size of the constitutive partieles of erystalline lattiee/networks numerous experimental or ealeulation methods have been proposed the present discussion follows (Chiriac-Putz-Chiriac, 2005). 

For instance, according to Pauling, the ionic radius can be ealeulated using the formula  

applying this formula for NaF, where both ions have the electronic configuration of neon, and shielding coefficient deduced from theoretical considerations, for example. Slater mles, is S = 4.52, see Volume II of the present five-volirme set, and Borg and Diens (1992) so we obtain  

Knowing the intemodal distance (accessible to direct determinations using 

However, the obtained values by different methods departs each other due to Ihe complexity of factors considered in modeling the influence of the inter-node distance. Regardless this difference, data analysis on nodal/ structural particle size highlights some very important regularity. They are  

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