Structural characterization of dimercury(1+) pentacyanonitrosylferrate(2-), Hg2[Fe(CN)5NO]

New powder X-ray diffraction data for magnesio-, ferro-, and manganaxinite, obtained from samples closely corresponding to the three end-members of the axinite mineral group, were obtained using a conventional Bragg-Brentano diffractometer. Space group is P 1. Powder patterns were indexed using Peacockʹs normal orientation, which gave: a = 7.1381(3), b= 9.1626(4), c =8.9421(4)A, (alpha)=91.903(4), (beta)=98.105(3), (gamma)=77.468(4)° for magnesioaxinite; a =7.1479(4), b=9.1962(5), c=8.9576(4)A, (alpha)=91.857(4), (beta)=98.177(4), (gamma)=77.359(4)° for ferroaxinite, and a=7.1849(4), b=9.2152(5), c=8.9765(4)A, (alpha)=91.761(4), (beta)=98.153(4), (gamma)= 77.150(4)° for manganaxinite. Peacockʹs orientation has been adopted in all recent structural and crystal chemical studies of axinite, but it differs from that reported on the JCPDS cards (29-344, 27-076 and 27-084, respectively). New data include an increased number of indexed peaks.