Ray Withers,
Chair of the Commission on Aperiodic Crystals of the IUCr.

The Commission has continued to be active in the promotion of Aperiodic Crystallography, in organizing meetings as well as in co-ordinating activities between the quasi-crystalline and incommensurate structure communities.

As part of these activities, the Commission continued to promote Aperiodic crystallography at national, regional and international meetings. During 2006, the triennial flagship meeting of the Commission, Aperiodic 2006, was held at the Miyagi Zao Royal Hotel in Zao, Miyagi prefecture, Japan from the 17th to the 22nd of September. Aperiodic 2006 was very ably organized by A.Yamamoto, A.P. Tsai, K.Saitoh, Y.Gotoh, Y.Miyazaki and Y.Michiue to whom the Aperiodic community is indebted for organizing such a stimulating and enjoyable meeting. The Conference Chairpersons were An Pang Tsai and Akiji Yamamoto. 128 delegates attended the conference coming from 21 different countries. Over half the delegates were from Asia with 60 coming from Japan alone (see the attached report of this meeting for more details). It was decided at this meeting that Aperiodic 2009 will be held in Liverpool, U.K probably in mid-September 2009 and will be organized by Ronan McGrath and Uwe Grimm (see http://www.liv.ac.uk/~mcgrath/aperiodic09.htm).

Further to the activities associated with Aperiodic 2006, a microsymposium on "Structure determination of modulated and aperiodic structures" as well as a Plenary lecture on "Incommensurate high pressure and high temperature structures in Group VI elements" were given as part of the 23rd European Crystallography Meeting, ECM-23, held in Leuven, Belgium from August 6 to 11. In addition, a microsymposium on "Crystal chemistry and complex superstructures" co organized by Sander van Smaalen was held during the German Crystallographic Association meeting held in Freiburg, Germany from April 3 to April 6.

Important upcoming activities for the Commission include the "Quasicrystals - the silver jubilee" meeting to be held in Tel Aviv, Israel from October 14 to 19 in 2007 (see http://www.congress.co.il/quasicrystals07/). This meeting is organized by Ron Lifshitz (Chair), Dan Shechtman and Shlomo Ben Abraham. Other up-coming activities include the 5th Workshop on the Structural Analysis of Aperiodic Crystals organized by Sander van Smaalen to be held from March 1 to March 4, 2007 at the University of Bayreuth in Germany.

The Commission maintains internet pages at the web site of the IUCr at http://www.iucr.org/iucr-top/comm/capd/index.html. A web site on all aspects of the crystallography of aperiodic crystals is maintained by the special interest group (SIG) on aperiodic crystals of the European Crystallographic Association. It is maintained by M. Dusek (Prague, Czech Republic), and it can be found at http://www-xray.fzu.cz/sgip/aphome.html.