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.

Call for Mentors

The ACA Speed Mentoring Sessions is an annual networking session hosted by the YSIG. The goal of this session is to provide ongoing mentorship for young scientists within the ACA and assist graduate students and postdocs who are preparing to start a new career. 

Interested?  Let us know by May 7th 


Call for Nominations

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 is now inviting nominations for its 2022 awards.  Find out how to submit a nomination and view past winners.

Bau Neutron Diffraction Award

Fankuchen Memorial Award

Kenneth N. Trueblood Award

Margaret C. Etter Early Career Award

Nominations are also being accepted for the ACA Fellows program.   View current ACA fellows and find details on how to submit a nomination.



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.



Get Involved at the ACA!

The ACA Nominating Committee is searching for candidates interested in running for election.  Read more...


Spring 2021 RefleXions


71st ACA Annual Meeting

Scientists interested in molecular and materials structure with specialties in biology, chemistry, geosciences, materials science and more will converge virtually for the 71st Annual Meeting of the ACA. The theme for the 2021 meeting is “Structural Science Awakens,” which celebrates the ACA’s new tagline “The Structural Science Society.” Scientific sessions and workshops will highlight new developments in single-crystal and powder diffraction, scattering, cryo-EM, micro-electron diffraction, and advanced capabilities at national x-ray, neutron, and EM facilities.




ACA Check-in & Chat

The next ACA Check-in & Chat is scheduled for April 29, 2021 @ 2:00 PM ET. Catch up with your colleagues and Council at our monthly ‘ACA Check-in & Chat’ over Zoom. Register today!