Question

9. Rhenium oxide has a cubic structure with the Re atoms sitting at the eight corners of the cube and the (O) atoms half way along the 12 edges of the cube: (a) Draw the structure and place the Re and O atoms in their positions (b) What is the molecular formula? contributions Explain your answer using fractional Re and O (c) What is the oxidation number of Re? (d) How many formula units per cell?, (e) Is the unit cell primitive or non-primitive? Explain. (f) What is the coordination of the Re atom (how many O anions surround the Re atom)? What in the coordination of the O anions? Does the answer make chemical sense? Explain (g) (h) Estimate the average Re-O bond length given that the unit cell parameter is: a 3.742 Å

Answer 1

cas o o I (by contribution of - 'Rel atom ? 188=1 of ou contribution a tom = formula 2 x 12 =3 = Re O₃

(C) oxidation Number 1. Of Re = +6 co: oxidation Number o in Ó =-2) of 2- (d) Number of formula units = 1 ces unit all is Non-Primitive fi coordination Number of pe=12 (g, coordination Number of 0=4 (h) 2 x 8 + 2x2 = a Petr a = 3:742 Aº 0 2 2 = 1:871 AO Re