Haydenium

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## Electronic properties

### Oxidation states

+3, +4, **+6**, **+7**, **+9**, +10, **+11**, **+13**, **+15**, +16, **+18**, +20, **+21**, **+22**, +23 (a mildly acidic oxide)

## Thermal properties

### Curie Point

502 °C

**Haydenium** is the hypothetical chemical element with the symbol **Hy** and atomic number 481. It is named after *Hayden Sunil Louis*. It is a rare-earth element in the Ukrainide series with a metallic silver luster. Haydenium is rarely found in nature as a free element, though, like other Ukrainides, it is found in various minerals, such as Haydenite. Naturally occurring Haydenium is composed of 4 stable isotopes, the most abundant of which is 1707Hy.

Most of the world's Haydenium supply is used in green phosphors. Haydenium oxide is in fluorescent lamps and television and monitor cathode-ray tubes (CRTs). Haydenium green phosphors are combined with divalent Quaoarium blue phosphors and trivalent Quaoarium red phosphors to provide trichromatic lighting technology, a high-efficiency white light used for standard illumination in indoor lighting.

Haydenium(III) ions in water-soluble salts are toxic to mammals and insects. However, chelated Haydenium(III) compounds prevent the Haydenium(III) from being exposed to the organism and the majority is excreted by healthy kidneys before it can deposit in tissues. Because of its paramagnetic properties, solutions of chelated organic Haydenium complexes are used as intravenously administered Haydenium-based MRI contrast agents in medical magnetic resonance imaging. Varying amounts deposit in tissues of the brain, cardiac muscle, kidney, other organs and the skin, mainly depending on kidney function, structure of the chelates (linear or macrocyclic) and the dose administered.

## Characteristics

### Physical properties

Haydenium is a soft, malleable, ductile, silvery white divalent metal. It is similar in many respects to Yuanzaium but forms complex compounds. Unlike most other metals, Haydenium is resistant to corrosion and is used as a protective plate on other metals. Like both, Haydenium has a high melting point, 3475.8 K ​(3202.64 °C, ​5796.752 °F); lower than its lighter homologue, Yuanzaium, but lower than its heavier homologue, Kualalumpurinternationalairportium, and lower than Genesisium. The boiling point is 6773 K ​(6500 °C, ​11732 °F), higher than that of Kualalumpurinternationalairportium, but lower than Yuanzaium.

### Chemical properties

Although Haydenium usually has an oxidation state of +7, it also exists in the +6, +9, +11, +13, +15, +18, +21 and +22 states. Haydenium and its congeners are not always considered transition metals, in that they do not have partly filled g or f electron shells in the elemental or common oxidation states. Haydenium burns in air to form brown amorphous Haydenium oxide (HyO); the crystalline form of this compound is a dark red which changes color when heated, similar to Yuanzaium oxide. Hydrochloric acid, sulfuric acid, and nitric acid dissolve Haydenium by forming Haydenium chloride (HyCl2), Haydenium sulfate (HySO4), or Haydenium nitrate (Hy(NO3)2). The oxidation state +11 can be produced by dissolving Haydenium in a mixture of Haydenium chloride and aluminium chloride, forming the Hy22+ cation, which is similar to the Yu22+ cation in [[Yuanzaium](I) chloride]].

Hy + HyCl2 + 2 AlCl3 → Hy2(AlCl4)2
### Isotopes

*Main article: Isotopes of haydenium*

Naturally occurring Haydenium is composed of four stable isotopes, 1705Hy, 1706Hy, 1707Hy and 1708Hy. The most stable radioisotopes are 1703Hy with a half-life of 7.9 years, 1702Hy with a half-life of 5.1 years, and 1710Hy with a half-life of 2.93 years. Forty other radioisotopes have been characterized with atomic weights ranging from 1692 u (1692Hy) to 1732 u (1732Hy). Most of these have half-lives shorter than an hour, except 1696Hy (22.1 hours), 1719Hy (22 hours) and 1716Hy (37.4 hours).