Copying pencil the wound. Such risks are not associated with ordinary graphite pencils. While these symptoms may appear after a couple of days they often develop only after weeks have passed since the injury was sustained. Surgery is required to remove the dye and the infected tissue and "the necrotizing action may be so severe and extensive amputation is necessary". Copying pencil A copying pencil, also indelible pencil or chemical pencil, is pencil whose lead contains a dye. The lead is fabricated by adding a dry water-soluble permanent dye to powdered graphite—used in standard graphite pencils—before binding the mixture with clay. Copying
Lead tetrachloride Lead tetrachloride Lead tetrachloride, also known as lead(IV) chloride, has the molecular formula PbCl. It is a yellow, oily liquid which is stable below 0 °C, and decomposes at 50 °C. It has a tetrahedral configuration, with lead as the central atom. The Pb–Cl covalent bonds have been measured to be 247 pm and the bond energy is 243 kJ⋅mol. Lead tetrachloride can be made by reacting lead(II) chloride PbCl, and hydrochloric acid HCl, in the presence of chlorine gas (Cl), leading to the formation of chloroplumbic acid HPbCl. It is then converted to the ammonium salt (NH)PbCl by adding