$(a)\;M_{\large\frac{x}{n}}\;[(AlO_{2})_{x}(SiO_{2})_{y}]mH_{2}O\qquad(b)\;M_{\large\frac{x}{n}}\;[(Al)_{x}(SiO_{2})_{3y}]mH_{2}O\qquad(c)\;M_{\large\frac{x}{n}}\;[(AlO_{2})_{x}(Si)_{y}]mH_{2}O\qquad(d)\;M_{\large\frac{x}{n}}\;[(AlO_{2})_{x}(SiO_{2})_{y}]$