The particle size, morphology, crystallization, and growth of calcium carbonate have been widely studied in the presence of organics, biomacromolecules, and biopolymers. Calcium carbonate with regular surface-relief structures has been synthesized by templating methods in the absence of dual negatively charged organic additives. Although a number of attempts have been made, the large-scale synthesis of 90 wt.% aragonite microrods by a facile route has hitherto remained difficult to achieve at temperatures below 60 degrees C. By using iminodiacetic acid as a crystal growth modifier, aragonite precipitated calcium carbonate (PCC) in the form of single-crystal microrods has been successfully synthesized at lower temperatures. It has been shown that the crystallographic and morphological characteristics of aragonite PCC microrods synthesized in the presence of iminodiacetic acid at a lower temperature are the same as those of aragonite obtained at 75 degrees C without an organic additive. The stereochemical relationship between calcium ions and the arrangement around ions bound to the carboxyl groups of iminodiacetic acid is suggested as a potential factor in the oriented nucleation and selectivity for formation of aragonite PCC microrods. The morphology, size, and crystal structure have been characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). (C) 2009 Elsevier B.V. All rights reserved.