Post-transition metal packing structure. Tin forms Zintl phases such as NaSn, BaSn, KSn and CaSn. It has good corrosion resistance in air on account of forming a thin protective oxide layer. Pure tin has no structural uses. It is used in lead-free solders, and as a hardening agent in alloys of other metals, such as copper, lead, titanium and zinc. Lead is a soft metal (MH 1.5, but hardens close to melting) which, in many cases, is unable to support its own weight. It has a close-packed structure (BCN 12) but an abnormally large inter-atomic distance that has been attributed to partial
Electrical connector called fork or split ring terminals). Electrical contact is made by the flat surface of the ring or spade, while mechanically they are attached by passing a screw or bolt through them. The spade terminal form factor facilitates connections since the screw or bolt can be left partially screwed in as the spade terminal is removed or attached. Their sizes can be determined by the size of the conducting wire AWG and the screw/bolt diameter size designation. In North American building wiring, twist-on wire connectors are frequently used in low-voltage power circuits for wires up to about #10 AWG in