1. Structural Chemistry and Berzelii Centre, EXSELENT on Porous Materials, Stockholm University, SE-106 91, Stockholm, Sweden


2. Instituto de Tecnología Química (UPV-CSIC), Av. Naranjos s/n, E-46022 Valencia, Spain

Correspondence to: Avelino Corma²Xiaodong Zou¹ Correspondence and requests for materials should be addressed to A.C. (Email: acorma@itq.upv.es) or X.Z. (Email: zou@struc.su.se).

The synthesis of crystalline molecular sieves with pore dimensions that fill the gap between microporous and mesoporous materials is a matter of fundamental and industrial interest^{1, 2, 3}. The preparation of zeolitic materials with extralarge pores and chiral frameworks would permit many new applications. Two important steps in this direction include the synthesis⁴ of ITQ-33, a stable zeolite with 18  10  10 ring windows, and the synthesis⁵ of SU-32, which has an intrinsically chiral zeolite structure and where each crystal exhibits only one handedness. Here we present a germanosilicate zeolite (ITQ-37) with extralarge 30-ring windows. Its structure was determined by combining selected area electron diffraction (SAED) and powder X-ray diffraction (PXRD) in a charge-flipping algorithm⁶. The framework follows the SrSi₂ (srs) minimal net⁷ and forms two unique cavities, each of which is connected to three other cavities to form a gyroidal channel system. These cavities comprise the enantiomorphous srs net of the framework. ITQ-37 is the first chiral zeolite with one single gyroidal channel. It has the lowest framework density (10.3 T atoms per 1,000 Å³) of all existing 4-coordinated crystalline oxide frameworks, and the pore volume of the corresponding silica polymorph would be 0.38 cm³ g^-1.