Provided is a method for preparing a stable amorphous calcium carbonate (ACC), which can be obtained either in suspension or as a powder. The method comprises stepwise combination of a soluble calcium salt, a soluble carbonate, a first and second stabilizer, and a water miscible organic solvent as described herein. The present invention further relates to stable ACC suspensions and dry powders produced by the method of the present invention.

Various embodiments may provide an electromechanical responsive film. The electromechanical responsive film may include a composition including sodium (Na), potassium (K), niobium (Nb) and oxygen (O). The composition may have a formula (Na.sub.xK.sub.y)NbO.sub.3-, wherein 0x<1, wherein 0y<1, and wherein 0<x+y<1. The composition may satisfy at least one condition selected from a group consisting of a first condition of (x+y+4)/2(3)(x+y+5)/2 and a second condition of 0<<1.