Einsteinium(III) oxide is an

oxide An oxide () is a chemical compound containing at least one oxygen atom and one other element in its chemical formula. "Oxide" itself is the dianion (anion bearing a net charge of −2) of oxygen, an O2− ion with oxygen in the oxidation st ...

of the

synthetic Synthetic may refer to: Science * Synthetic biology * Synthetic chemical or compound, produced by the process of chemical synthesis * Synthetic elements, chemical elements that are not naturally found on Earth and therefore have to be created in ...

actinide The actinide () or actinoid () series encompasses at least the 14 metallic chemical elements in the 5f series, with atomic numbers from 89 to 102, actinium through nobelium. Number 103, lawrencium, is also generally included despite being part ...

einsteinium Einsteinium is a synthetic chemical element; it has symbol Es and atomic number 99 and is a member of the actinide series and the seventh transuranium element. Einsteinium was discovered as a component of the debris of the first hydrogen bomb ...

which has the

molecular formula A chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as paren ...

Es₂O₃. It is a colourless solid. Three modifications are known. The

body-centered cubic In crystallography, the cubic (or isometric) crystal system is a crystal system where the Crystal structure#Unit cell, unit cell is in the shape of a cube. This is one of the most common and simplest shapes found in crystals and minerals. There ...

form has

lattice parameter A lattice constant or lattice parameter is one of the physical dimensions and angles that determine the geometry of the unit cells in a crystal lattice, and is proportional to the distance between atoms in the crystal. A simple cubic crystal has ...

''a'' = 1076.6 ± 0.6 pm; this allows the

ionic radius Ionic radius, ''r''ion, is the radius of a monatomic ion in an ionic crystal structure. Although neither atoms nor ions have sharp boundaries, they are treated as if they were hard spheres with radii such that the sum of ionic radii of the cati ...

of the Es³⁺

ion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...

to be calculated as 92.8 pm. The other two forms are

monoclinic In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three Vector (geometric), vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in t ...

and

hexagonal In geometry, a hexagon (from Greek , , meaning "six", and , , meaning "corner, angle") is a six-sided polygon. The total of the internal angles of any simple (non-self-intersecting) hexagon is 720°. Regular hexagon A regular hexagon is d ...

: the hexagonal form has the

lanthanum(III) oxide Lanthanum(III) oxide, also known as lanthana, chemical formula , is an inorganic compound containing the rare earth element lanthanum and oxygen. It is used in some ferroelectric materials, as a component of optical materials, and is a feedstock ...

structure.R. G. Haire, L. Eyring, in: ''Handbook on the Physics and Chemistry of Rare Earths'', Vol. 18 ''Lanthanoids and Actinides Chemistry'' (hrsg. von K. A. Gscheidner, Jr., L. Eyring, G. R. Choppin, G. H. Lander), North-Holland, New York 1994, S. 414–505. Einsteinium(III) oxide can be obtained by annealing einsteinium(III) nitrate in sub-

microgram In the metric system, a microgram or microgramme is a unit of mass equal to one millionth () of a gram. The unit symbol is μg according to the International System of Units (SI); the recommended symbol in the United States and United Kingdom wh ...

quantities.R. G. Haire, R. D. Baybarz: "Identification and Analysis of Einsteinium Sesquioxide by Electron Diffraction", in: ''

Journal of Inorganic and Nuclear Chemistry ''Polyhedron'' is a peer-reviewed scientific journal covering the field of inorganic chemistry. It was established in 1955 as the ''Journal of Inorganic and Nuclear Chemistry'' and is published by Elsevier. Abstracting and indexing ''Polyhedron' ...

'', 1973, ''35'' (2), S. 489–496; .

References

Further reading