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
Hard and soft C spelling, as shown in the title of one of his books, "Đường kách mệnh". Hard and soft C In the Latin-based orthographies of many European languages (including English), a distinction between hard and soft occurs in which represents two distinct phonemes. The sound of a hard (which often precedes the non-front vowels , and ) is that of the voiceless velar stop, (as in "car") while the sound of a soft (typically before , and ), depending on language, may be a fricative or affricate. In English, the sound of soft is (as in "citrus"). There was no soft in