A new Zintl phase NaGaSn2 is obtained pure from stoichiometric reactions of the elements in sealed Ta at similar to 450 degrees C. Its orthorhombic framework structure (space group C222(1), 6.309(3) x 10.986(4) x 6.162(4) Angstrom) contains one-dimensional helical pores similar to 6 Angstrom in diameter along (c) over right arrow (6 atoms/turn) that bind relatively well-ordered sodium countercations at 50% occupancy. The structure can also be described in terms of interlinked puckered double layers normal to (b) over right arrow and parallel to the channels. Gallium is disordered over both tetrahedral framework sites, the gallium-richer and more negative site having closer sodium neighbors. The potassium compound cannot be made. Among analogous phases reported by others, NaInSn2 has a lower symmetry and ordered cations, while NaGaSn5 cannot be reproduced.