The crystal structure of niobium oxide diiodide NbOI2

Abstract The crystal structure of NbOI 2 was determined by X-ray diffraction using single-crystal diffractometer data obtained with Mo K α radiation. The compound is monoclinic with a = 15.184(2) A ; b = 3.924(1) A ; c = 7.520(1) A ; β = 105.50(1)°. The metal is surrounded by distorted I 4 O 2 octahedra which share I-I edges and O corners with four other octahedra to form sheets parallel to (100). The metal atoms are displaced from the centers of the octahedrons to form Nb-Nb pairs (3.16 A ). It could not be decided whether the metal atoms lie in the mirror planes of the I 4 O 2 octahedra (MoOCl 2 type, space group C2 m ) or whether they are slightly (0.13 A) displaced from these planes (NbOCl 2 type, space group C 2).