Calcium chloride dihydrate

Calcium Chloride is a widely used reagent in the research of biochemistry.
Calcium play roles of great importance in physiological function, including signal transmitting, muscle contraction, and maintenance of cell morphology and stability. Chloride ions are essential in body fluids which maintain the acid/base balance and transduce nerve impulses.
Calcium Chloride is used in the preparation and transformation of competent Escherichia. Coli and in the transfection of eukaryotic cells with either plasmid DNA or high molecular weight genomic DNA. CaCl2 has been used in the stabilization and two-dimensional crystallization of the NADH-ubiquinone oxidoreductase from E. coli. The crystallization of procine pancreatic elastase in the presence of CaCl2 in the presence of sodium citrate reveals binding of calcium in the metal binding site of the protein. [1]
Calcium chloride was also assessed for its ability to bind dietary phosphorus both in vivo and in vitro. The outcome revealed that inhibition of phosphorus absorption by calcium chloride involves a complex interplay between chemical reactions and ion transport processes in the stomach and small intestine. Moreover, calcium chloride was assessed for the rapidity of reaction at pH 7 which showed 99% binding at 10 min. Calcium chloride is also a convenient and reliable reagent for creating aneurysm model. Doses of 13.6 mEq/10 ml calcium chloride solution were administrated to the abdominal aorta of nine mice daily. The diameters of vessel were measured in 7-day intervals and had significant increasing, which could be results of inflammatory infiltrates in the intima and media layers underlying mechanisms for this model include disrupting the elastic network within the media by calcium precipitations and activating the inflammatory response. [2, 3]
References:
[1] Dagert, M., and S. D. Ehrlich. "Prolonged incubation in calcium chloride improves the competence of Escherichia coli cells." Gene 6.1 (1979): 23-28.
[2] Sheikh, Mudassir S., et al. "Reduction of dietary phosphorus absorption by phosphorus binders. A theoretical, in vitro, and in vivo study." Journal of Clinical Investigation 83.1 (1989): 66.
[3] Chiou, Andy C., Bill Chiu, and William H. Pearce. "Murine aortic aneurysm produced by periarterial application of calcium chloride." Journal of Surgical Research 99.2 (2001): 371-376.

Calcium chloride rhenate(VII) dihydrate.[Pubmed:17762100]

Acta Crystallogr C. 2007 Sep;63(Pt 9):i77-9.

The crystal structure of calcium chloride rhenate(VII) dihydrate, CaCl(ReO4).2H2O, investigated at 85 K, consists of calcium cations, chloride anions, rhenate(VII) anions and water molecules. In the nearly tetrahedral rhenate(VII) anion, all constituent atoms lie on special positions of m2m (Re) and m (O) site symmetries. The Cl- anion and water O atom lie on special positions of m2m and 2 site symmetries, respectively. The Ca2+ ion, also on a special position (m2m), is eight-coordinated in a distorted square-antiprismatic coordination mode. The crystal has a layered structure stabilized by Ca-O coordination bonds and O-H...Cl hydrogen bonds.

Structure of the X-phase of 38% brominated betaine calcium chloride dihydrate.[Pubmed:11373387]

Acta Crystallogr B. 2001 Jun;57(Pt 3):296-302. Epub 2001 Jun 1.

The structures of the high- and low-temperature phases of 38% brominated BCCD [betaine (trimethylammonioacetate) Calcium chloride dihydrate], the latter being known as the X-phase, have been determined by single-crystal neutron diffraction at 295 and 20 K, respectively. The symmetry of the X-phase is described by the P2(1)2(1)2(1) space group. The distortion with respect to the high-temperature Pnma phase is characterized by anti-symmetric displacements of the betaine molecules as well as of the Ca octahedra. On the basis of a symmetry-mode analysis, we propose an interpretation of the direct phase transition that occurs around 80 K between these two phases.