Evidence of structural variability among synthetic and biogenic vaterite.

Recently, the results of experimental and theoretical investigations have revealed that, in vaterite, two or even more crystalline structures coexist. In this communication we report evidence of diverse vaterite structures in biogenic samples of different origin. In addition, it is shown that the synthetic vaterite precipitated in the presence of poly-l-aspartate has structures similar to those of biogenic samples.