Chemical properties are only observable during a chemical reaction. Thermal conductivity: 150 W m ‑1 K ‑1; Coefficient of linear thermal expansion: 2.6 × 10 ‑6 K ‑1; Optical properties. Pure silicon is a hard, dark gray solid with a metallic lustre and with a octahedral crystalline structure the same as that of the diamond form of carbon, to which silicon shows many chemical and physical similarities. At red heat, silicon is attacked by water vapour or by oxygen, forming a surface layer of silicon dioxide. Physical properties include things like the freezing point and density. The image above is a virtual representation of silicon metal calculated by Patrick Callet using the complex diectric function of the element only. For use in electronic devices, single crystals are grown by slowly withdrawing seed crystals from molten silicon. Elemental silicon is produced commercially by the reduction of silica (SiO2) with coke in an electric furnace, and the impure product is then refined. The Physical properties of Silicon are the characteristics that can be observed without changing the substance into another substance. The limited number of silicon atoms that can catenate, however, greatly reduces the number and variety of silicon compounds compared with those of carbon. Certainly, many of the naturally occurring compounds called silicates were used in various kinds of mortar for construction of dwellings by the earliest people. Compared with the maximum of about 8.7 million electron volts for the nucleus of iron, almost twice as massive as that of silicon, this figure indicates the relative stability of the silicon nucleus. Only the 0 and +4 oxidation states of silicon are stable in aqueous systems. https://www.britannica.com/science/silicon, Science Kids - Fun Science and Technology for Kids - Silicon Facts, Amethyst Galleries' Mineral Gallery - The Mineral Silicon, silicon - Student Encyclopedia (Ages 11 and up). In compounds, silicon dioxide occurs both in crystalline minerals (e.g., quartz, cristobalite, tridymite) and amorphous or seemingly amorphous minerals (e.g., agate, opal, chalcedony) in all land areas. The name silicon derives from the Latin silex or silicis, meaning “flint” or “hard stone.” Amorphous elemental silicon was first isolated and described as an element in 1824 by Jöns Jacob Berzelius, a Swedish chemist. The Physical and Chemical Properties are the characteristics of a substance, like Silicon, which distinguishes it from any other substance. Its compounds also occur in all natural waters, in the atmosphere (as siliceous dust), in many plants, and in the skeletons, tissues, and body fluids of some animals. When silicon and carbon are combined at electric furnace temperatures (2,000–2,600 °C [3,600–4,700 °F]), they form silicon carbide (carborundum, SiC), which is an important abrasive. Refer to the article on Silicon for additional information and facts about this substance. Only hydrogen, helium, oxygen, neon, nitrogen, and carbon exceed silicon in cosmic abundance. Allotropes are the element forms which have various chemical and physical properties. Inhalation of dusts containing alpha SiO2, however, produces a serious lung disease called silicosis, common among miners, stonecutters, and ceramic workers, unless protective devices are used. One allotrope is in the form of shiny, grayish-black, needle-like crystals, or flat plates. As is true with carbon, the bonds in elemental silicon are strong enough to require large energies to activate, or promote, reaction in an acidic medium, so it is unaffected by acids except hydrofluoric. It is a non-metallic element occurring extensively in the earth's crust in silica and silicates, having both an amorphous and a crystalline allotrope. In the form of rock crystal, however, silicon was familiar to the predynastic Egyptians, who used it for beads and small vases; to the early Chinese; and probably to many others of the ancients. Indeed, human tissue often contains 6 to 90 milligrams of silica (SiO2) per 100 grams dry weight, and many plants and lower forms of life assimilate silica and use it in their structures. Electrical properties. Tables of Physical & Chemical Constants, Kaye & Laby Online, 16th edition, 1995. What are the Physical Properties of Silicon? Physical properties Silicon is a metalloid, an element with properties of both metals and non-metals. Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree.... Overview of silicon, including mining and processing.