The main physical properties of rare earth metals

MIRAMAR, Fla. - April 10, 2020 - PRLog -- Rare earth metals (https://www.edgetechree.com/) as additives to magnesium, aluminum and their alloys, the first thing to consider is their density. The density depends on the relative atomic mass, atomic radius, and crystal structure of the rare earth metal. The density of Yttrium is 4.46g/cm3, which is larger than that of Scandium (https://www.edgetechree.com/rare-earth-metals/scandium-metal/), but it has a smaller atomic weight than that of lanthanide, and is intermediate between scandium and lanthanide metals (from Lanthanum to Lutetium). Among all lanthanide metals, due to the shrinkage of the lanthanide series and the increase in atomic weight, their density generally increases with the increase of the atomic number, which increases by about 60% from Lanthanum to Lutetium (https://www.edgetechree.com/rare-earth-metals/lutetium-metal/). Europium and Ytterbium being exceptions, they have an unusually large atomic radius, and their density is smaller than that of their neighboring rare earth metals.

The rule that the melting point of lanthanide metals changes with atomic number is similar to the rule that the density of lanthanide metals increases with increasing atomic number, except for lanthanum metal (https://www.edgetechree.com/rare-earth-metals/lanthanum-m...). Starting from cerium, the melting point of lanthanide metals increases with increasing atomic number. The melting point from Cerium (https://www.edgetechree.com/rare-earth-metals/cerium-metal/) to Lutetium has increased by approximately 110%. However, this rule does not suitable for Europium and Ytterbium (https://www.edgetechree.com/rare-earth-metals/ytterbium-metal/). The melting points of these two metals are lower than that of their neighboring rare earth metals. The melting point of yttrium is close to the middle value of the yttrium (https://www.edgetechree.com/rare-earth-metals/yttrium-metal/) subgroup element. The melting point of Erbium (https://www.edgetechree.com/rare-earth-metals/erbium-metal/) is 1529°C, yttrium is 1522°C, and the melting point of scandium is 1541 ° C.

The melting heat and elastic modulus of lanthanide metals also show a similar law, which changes with the change of atomic number. The heat of fusion and the modulus of scandium and yttrium are within the limits of the yttrium subgroup element. However, there are cases that do not meet the above rules. The elastic modulus of Samarium is even lower than that of Promethium and Neodymium, and the heat of fusion of Europium (https://www.edgetechree.com/rare-earth-metals/europium-metal/) is between of Promethium and Gadolinium (https://www.edgetechree.com/rare-earth-metals/gadolinium-metal/).