1. A microporous crystalline zeolite having a three-dimensional framework of at least AlO2 and SiO2 tetrahedral units and an empirical composition on an anhydrous basis in terms of mole ratios of the elements of:
M1an+Al(1−x)ExSiy′Oz″ where M1 is at least one exchangeable cation selected from the group consisting of alkali metals, alkaline earth metals, rare
earth metals, ammonium ion, hydrogen ion and mixtures thereof, a is the mole ratio of M1 to (Al+E) and varies from 0 to about
50, E is an element selected from the group consisting of gallium, iron, boron, chromium, indium and mixtures thereof, x is
the mole fraction of E and vanes from 0 to about 0.5, n is the weighted average valence of M1 and has a value of about +1
to about +3, y′ is the mole ratio of Si to (Al+E) and is greater than about 5 and z″ is the mole ratio of O to (Al+E) and
has a value determined by the equation:
z″=(a·n+3+4·y′)/2
the zeolite characterized in that it has at least two x-ray diffraction peaks, one at a d-spacing of 3.84±0.07 Å and one at
a d-spacing of 8.55±0.25 Å, and has a tetragonal unit cell.
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