Mechanical pencil applied at an angle. When excess vertical pressure is applied on the lead, the lead is automatically retracted inwards. Higher-end mechanical pencils often feature a lead hardness grade indicator and sometimes feature a retractable lead guide pipe. This allows the lead guide pipe to retract back into the pencil body, which will keep it protected in storage and during transit and makes it 'pocket-safe'. In spite of the name, pencil leads do not contain the toxic chemical element lead, but are typically made with graphite and clay, or plastic polymers. Compared to standard pencils, mechanical pencils have a smaller range
Lead(II) thiocyanate has not been confirmed by other sources than the author of this article, experiments show that even if there is no precipitation of lead(II) thiocyanate in the solution, crystals of the salt may form. Lead(II) thiocyanate can be formed from the acidification of Lead Nitrate Pb(NO) with nitric acid (HNO) in the presence of Thiocyanic acid (HSCN) Lead(II) thiocyanate may be made by reacting lead(II) acetate (Pb(CHCOO)) solved in water with either potassium thiocyanate (KSCN) or ammonium thiocyanate (NHSCN), thus causing a white precipitation of solid lead(II) thiocyanate. Ion reaction: When exposed to UV or visible light lead thiocyanate will