Two corrections are made to a previous paper on the subject. The proposed space group is changed from Am2m to Cm2m and atoms with x co-ordinates of 3/5, 4/5 and 2/3 in a super unit cell are eliminated, The changes have no effect on the conclusion that the

X. Meng-Burany ، نويسنده , , A. E. Curzon، نويسنده ,

356674