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v. t. e. In chemistry, a transition metal (or transition element) is a chemical element in the d-block of the periodic table (groups 3 to 12), though the elements of group 12 (and less often group 3) are sometimes excluded. The lanthanide and actinide elements (the f-block) are called inner transition metals and are sometimes considered to be ...
Aluminium sometimes is [75] or is not [76] counted as a post-transition metal. It has a well shielded [Ne] noble gas core rather than the less well shielded [Ar]3d 10, [Kr]4d 10 or [Xe]4f 14 5d 10 core of the post-transition metals. The small radius of the aluminium ion combined with its high charge make it a strongly polarizing species, prone ...
Cementite (or iron carbide) is a compound of iron and carbon, more precisely an intermediate transition metal carbide with the formula Fe 3 C. By weight, it is 6.67% carbon and 93.3% iron. It has an orthorhombic crystal structure. [4] It is a hard, brittle material, [4] normally classified as a ceramic in its pure form, and is a frequently ...
Lawrencium is a synthetic chemical element; it has symbol Lr (formerly Lw) and atomic number 103. It is named after Ernest Lawrence, inventor of the cyclotron, a device that was used to discover many artificial radioactive elements. A radioactive metal, lawrencium is the eleventh transuranium element, the third transfermium, and the last member ...
A fusible alloy is a metal alloy capable of being easily fused, i.e. easily meltable, at relatively low temperatures. Fusible alloys are commonly, but not necessarily, eutectic alloys. Sometimes the term "fusible alloy" is used to describe alloys with a melting point below 183 °C (361 °F; 456 K). Fusible alloys in this sense are used for solder.
Boron is a lustrous, barely reactive solid with a density 2.34 g/cm 3 (cf. aluminium 2.70), and is hard (MH 9.3) and brittle. It melts at 2076 °C (cf. steel ~1370 °C) and boils at 3927 °C. Boron has a complex rhombohedral crystalline structure (CN 5+). It is a semiconductor with a band gap of about 1.56 eV.
Potassium is a chemical element; it has symbol K (from Neo-Latin kalium) and atomic number 19. It is a silvery white metal that is soft enough to easily cut with a knife. [8] Potassium metal reacts rapidly with atmospheric oxygen to form flaky white potassium peroxide in only seconds of exposure.
MAX phases. The MAX phases are layered, hexagonal carbides and nitrides which have the general formula: M n+1 AX n, (MAX) where n = 1 to 4, [1] and M is an early transition metal, A is an A-group (mostly IIIA and IVA, or groups 13 and 14) element and X is either carbon and/or nitrogen. The layered structure consists of edge-sharing, distorted ...