Ne. Ghermani et al., ELECTROSTATIC PROPERTIES IN ZEOLITE-TYPE MATERIALS FROM HIGH-RESOLUTION X-RAY-DIFFRACTION - THE CASE OF NATROLITE, Physical review. B, Condensed matter, 53(9), 1996, pp. 5231-5239
High-resolution x-ray-diffraction data of natrolite at room temperatur
e give by multipolar refinement an analytical expression of the electr
on density which permits the calculation of net atomic charges and ele
ctrostatic potential. The observed net charges show that the structura
l formula of natrolite may be written Na2Al2Si2O8(SiO2),2H(2)O. The el
ectrostatic energy of one sodium ion inside the crystal is estimated t
o -21.6 eV. Calculation of the electrostatic potential excluding one s
odium shows that the minimum is precisely at the removed Na position.