Structure Matters!

Welcome to the American Crystallographic Association. The American Crystallographic Association, Inc. (ACA) is a non-profit, scientific organization of over a thousand members in more than thirty-five countries. The ACA was founded in 1949 through a merger of the American Society for X-Ray and Electron Diffraction (ASXRED) and the Crystallographic Society of America (CSA). The objective of the ACA is to promote interactions among scientists who study the structure of matter at atomic (or near atomic) resolution. These interactions will advance experimental and computational aspects of crystallography and diffraction. Understanding the nature of the forces that both control and result from the molecular and atomic arrangements in matter will help shed light on chemical interactions in nature.


Membership in the ACA is open to any person who is actively interested in the purposes of the Association. The ACA welcomes everyone from students to retirees. All of our members contribute to the life and vigor of the Association.

Your membership helps the ACA share our scientific passions and accomplishments through different approaches, including the annual conference, our publications and educational outreach.

The ACA was established to connect scientists and anyone interested in crystallography and the ACA strives to continue to reach that goal today. As we progress forward the ACA remembers and memorializes our past crystallographic discoveries and achievements. It is with our history and achievements that the ACA hopes to inspire future generations of explorers, scientists and crystallographers.

As a student, let the ACA inspire you to dive into physics, math and chemistry. As a grad or undergrad let the ACA help you establish your professional network. Regular members share research, accomplishments and curate industry connections. Retired members help remember our history and encourage future crystallographers.


Call for Nominations!

New Deadline: May 1st!

The ACA recognizes distinguished achievement in the field of crystallography to both mature and early career crystallographers through the presentation of various annual awards and prizes.

The ACA relies on its experienced membership to recognize and bring attention to the accomplishments and contributions of their fellow members and colleagues. Complete and submit a nomination today:

2021 Buerger Award
2021 Warren Award
2021 Etter Award
Nominate an ACA Fellow



Special Article: Crystallography & COVID-19

With new cases of the coronavirus disease 2019 (COVID-19) climbing steeply across the globe, everyone has an interest in solving COVID-19 challenges, but crystallography has a special role to play.  Read an overview about structural science and COVID in a special article published through the ACA: Through the Crystal Ball: The role of Crystallography and other Structural Science in COVID-19 therapies by ACA Vice President, David Rose.  

The Future of the ACA:

This year we would like to put together a collage of YSIG members for the cover of our summer RefleXions issue! If you would like to participate please forward a selfie to Paul Swepston (Co-Editor of RefleXions) at [email protected] by May 1st to be included.


2020 ACA Annual Meeting:


Reserve a Hotel Room
Sponsor a Session


“Training the Next Generation”  

Scientists interested in molecular and materials structure with specialties in biology, chemistry geosciences, materials science and much more will converge on the San Diego waterfront in August 2020 for exchange of scientific research and technique know-how for the 70th Annual Meeting of the ACA.