Formula unit Formula unit A formula unit in chemistry is the empirical formula of any ionic or covalent network solid compound used as an independent entity for stoichiometric calculations. It is the lowest whole number ratio of ions represented in an ionic compound. Examples include ionic NaCl and KO and covalent networks such as SiO and C (as diamond or graphite). Ionic compounds do not exist as individual molecules; a formula unit thus indicates the lowest reduced ratio of ions in the compound. A "chemical formula" shows the kinds and numbers of atoms in the smallest representative unit of a substance. In
Chemical compound microarray Polymer microarrays have been developed to allow screening for new polymeric materials to direct different tissue lineages. Research has also been directed towards studying the surface chemistry of these arrays to determine which surface chemistries control cell adhesion, although concerns have been raised as to the influence of the substrate on measurements and the questionable statistical interpretation of results. The lack of control in the production of many of these polymer arrays suggests that any practical application of these technologies will be limited. This is particularly true for the in situ polymerisation of acrylate monomers in minute volumes. Chemical compound