Cerium
Cerium (Ce), chemical element, the most abundant of the rare-earth metals. Commercial-grade cerium is iron-gray in colour, silvery when in a pure form, and about as soft and ductile as tin. It oxidizes in air at room temperature to form CeO2. The metal slowly reacts with water, and it quickly dissolves in diluted acids, except hydrofluoric acid (HF) that leads to the formation of the protective fluoride (CeF3) layer on the surface of the metal. Cerium turnings (from when the metal is filed, ground, or machined) easily self-ignite in air, burning white-hot. Its pyrophoric nature accounts for one of its important metallurgical applications in lighter flints. The metal should be stored either in vacuum or in an inert atmosphere. The metal is a moderately strong paramagnet both below and above room temperature and becomes antiferromagnetic below 13 K (−260 °C, or −436 °F). It becomes superconducting in the millikelvin range at pressures exceeding 20 kbar.
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Beryllium is a toxic bivalent element, steel gray, strong, light-weight, primarily used as hardening agent in alloys. Beryllium has one of the highest melting points of the light metals. It has excellent thermal conductivity, is nonmagnetic, it resists attack by concentrated nitric acid and at standard temperature and pressures beryllium resist oxidation when exposts to …
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Francium (Fr), heaviest chemical element of Group 1 (Ia) in the periodic table, the alkali metal group. It exists only in short-lived radioactive forms. Natural francium cannot be isolated in visible, weighable amounts, for only 24.5 grams (0.86 ounce) occur at any time in the entire crust of Earth. The existence of francium was predicted …
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Arsenic is a chemical element with the symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. Allotropes: grey (most common), yellow, black … Atomic number (Z): 33 CAS Number: 7440-38-2 Natural occurrence:
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An ironstone (76) is a sedimentary rock that contains more than 15% iron, which may be present as variable proportions of iron-bearing minerals such as goethite, siderite, and berthierine. Sedimentary ironstones may be hard and calcareous and contain quartz grains, ooliths, pebbles, and a wide variety of macrofossils. The Frodingham Ironstone bed comprises a lenticular …
