Electrical Properties of Niobium Tetrachloride

The role of d orbitals on phosphorus in the bonding of trimethylphosphine and tris(trifluoromethyl)phosphine

“…Thus our study shows that the role of phosphorus d orbitals in P(CH3)3 and P(CF3)3 is not counterintuitive but normal, in agreement with the observation of Collins et al 5 In accounting for the long P-C bond of P(CF3)3, the concept of counterintuitive orbital interaction remains valid since it provides a mechanism by which electron density shifts from the electropositive region of P-C bond to the electronegative region of C-F bond.4 However, this electron shift is not due to phosphorus d orbitals as indicated by the extended Hückel calculations.1 Use of the weighted Hformula is found to greatly reduce the extent of counterintuitive orbital interaction in extended Hückel calculations on P(CF3)3, as in the case of molecules containing transition-metal atoms.2 Tight-binding band calculations were performed on NbOCl2 net to examine the effect of Nb-Nb-Nb and Nb-O-Nb alternations on the electronic structure of NbOCl2 net. The out-of-plane Nb displacement is found as crucial as the pairing distortion of Nb atoms for the semiconducting property of NbOX2 net.…”

TaI2Cl2, eine neue Verbindung vom MX4-Typ (M=Nb, Ta; X=Cl, Br, I) / TaI2Cl2, A New Compound of the MX4-Type (M=Nb, Ta; X=Cl, Br, I)

“…B. in Z rl3 [1] und NbCl4 [2][3][4][5] lange diskutiert. Von den Niobtetrahalogeniden sind inzwischen die K ristallstrukturen von a-N bI4 [6] und NbCl4 [5] (N bF 4 kristallisiert in einer Schichtstruktur) aufgeklärt und hinsichtlich ihrer Leitungseigenschaften [7][8][9] und ihrer Elektronen struktur [10][11][12] intensiv untersucht worden. Die entsprechenden Tantaltetrahalogenide gelten als isotyp [13] mit NbCl4.…”