CRYSTAL-STRUCTURE, ELECTRICAL-TRANSPORT, AND MAGNETIC-PROPERTIES OF NIOBIUM MONOPHOSPHIDE

Citation
J. Xu et al., CRYSTAL-STRUCTURE, ELECTRICAL-TRANSPORT, AND MAGNETIC-PROPERTIES OF NIOBIUM MONOPHOSPHIDE, Inorganic chemistry, 35(4), 1996, pp. 845-849
Citations number
21
Categorie Soggetti
Chemistry Inorganic & Nuclear
Journal title
ISSN journal
00201669
Volume
35
Issue
4
Year of publication
1996
Pages
845 - 849
Database
ISI
SICI code
0020-1669(1996)35:4<845:CEAMON>2.0.ZU;2-2
Abstract
Large single crystals of NbP have been prepared. A single-crystal X-ra y diffraction study shows that it crystallizes in tetragonal symmetry with space group I4(l)md (No. 109) and lattice parameters a = 3.3324(2 ) Angstrom, c = 11.3705(7) Angstrom, and Z = 4. A full matrix least-sq uares refinement based on a unique data set of 285 reflections (I > 2 sigma(I)) yielded R(F) = 0.017 and R(w)(F-2) = 0.046 for nine variable s. The unit cell consists of one unique Nb and one P, each in trigonal prismatic coordination with the other element. There are two short an d four long bond distances of Nb-P. The Nb-Nb bond distances are signi ficantly shorter than R(c) = 4.09 Angstrom, the critical distance requ ired for good Nb-Nb 4d orbital overlap for niobium metal-metal bonds. NbP shows metallic behavior with rho = 4.5 x 10(-5) Omega cm at room t emperature. Magnetic susceptibility measurements on a collection of ra ndomly oriented single crystals indicate very weak Pauli paramagnetism (similar to 10(-5) emu/mol). A discussion of the structure as well as the physical properties of NbP compared with those of previous result s are presented. The band structure of NbP based on the extended Hucke l (tight-binding) calculations is presented along with an, analysis th at reveals that the valence band is built up from three center bonds l ocalized within Nb-3 triangles.