Silicon biogenic silicate, silica

Silicon isotope variations in the ocean are caused by biological Si-uptake through siliceous organisms like diatoms. Insofar strong similarities exist with C-isotope variations. Diatoms preferentially incorporate Si as they form biogenic silica. Thus, high 5 °Si values in surface waters go parallel with low Si-concentrations and depend on differences in silicon surface water productivity. In deeper waters dissolution of sinking silica particles causes an increase in Si concentration and a decrease of 5 °Si-values. 

Summary The possibility of direct synthesis of silicon oi anic compounds based on hydrolysis-resistant organic derivatives of silicon by using biogenic silica (from siliceous rocks) as a new raw material is discussed. The complex triethylphosphate with silica, the ammonium salts of tricatechol, and humic acids of monosilicic acids were obtained. Products were identified by proton magnetic resonance spectroscopy, IR spectrophotometry, or elemental analysis. 

To conclude, it is necessary to note that the reaction ability of biogenic silica depends on its structure and solubility, determined by various factors. It has been found that soluble forms of silica could be stabilized by S - 7% of glycerin and catechol. It has been determined that the amorphous part of the biogenic silica of siliceous rocks formed the complex with triethylphosphate and actively reacts with polyphenols (the simple one, catehol and complex ones, humic acids), with formation of ethers. The silicon organic derivatives and complexes formed are inert to hydrolysis. 

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