There is no chemical difference between biologically produced and chemically produced alcohols. Other organolead compounds are less chemically stable. Proteins can be biotinylated chemically or enzymatically. Oligonucleotides are chemically synthesized from protected phosphoramidites of natural or chemically modified nucleosides. Taconite tailings are mostly the mineral quartz, which is chemically inert. This tubing provides adequate chemical compatibility and life to be used in chemically challenging applications. Lithium fluoride is exceptionally chemically stable and LiF-BeF mixtures have low melting points. Biochromes are colors chemically formed microscopic, natural pigments. Radical species contain unpaired electron atoms and are very chemically active. Rayon is a semi-synthetic fiber made by chemically reshaping cellulose. For binary mixtures of two chemically independent components, so that . Others work by chemically or physically removing or sequestering the impurity. Carbon monoxide is the primary ingredient of chemically stripping oxygen from iron. Carbonate minerals are extremely varied and ubiquitous in chemically precipitated sedimentary rock. Minerals are chemically pure solids found in nature.