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.