Studies on the Relationship between Structural Parameter F and △_fH_m^Φ of Some Gaseous Compounds

The structural parameter F is defined as by multiplication of three matrices L. W. X.F=LWX, From the multplication of the matrices we can see that F is the sum of the contributions of each atom in a molecule,F=\sum_i=1^n\left(\delta_i \sum_j=1^r X_j\right)=\sum_i=1^n C_i, \quad \delta_i=\fracZ_in_i^*, \quad X_j=\frac1+\Delta I_jR_j Z_i is the number of valence electrons （oxidation number is negative） or the number of bonded electrons （oxidation number is positive） of atoms, n_i* is the highest effective main quantum number of atom i, R_j is bond length or the sum of covalent radius of bond j, △I_j is the difference of pauling’s electronegativity of the atoms which are linked up by bond j. The values of F for the molecules of SiH_mX_n, TiX_n, CH_mX_n （X=F, CI, Br, I） are calculeted. It is satisfactory that the good relationships between F and △_fH_m^Φ of the compounds are obtained obtained:SiH_mX_n+TiX_n △_fH_m^Φ= 367.0125 - 37.7598F, R =0.9703, n =48,CH_mX_n: △_fH_m^Φ= 518.2873 - 23.7316F, R =0.9925, n=44.