Hf
[医] 铃(72号元素)



hf
[ noun ]

1. a grey tetravalent metallic element that resembles zirconium chemically and is found in zirconium minerals; used in filaments for its ready emission of electrons

<noun.substance>

2. 3 to 30 megahertz

<noun.attribute>

Hydrofluoric \Hy`dro*flu*or"ic\, a. [Hydro-, 2 + fluoric.]
(Chem.)
Pertaining to, or containing, hydrogen and fluorine;
fluohydric; as, hydrofluoric acid.

{Hydrofluoric acid} (Chem.), a colorless, mobile, volatile
liquid, {HF}, very corrosive in its action, and having a
strong, pungent, suffocating odor. It is produced by the
action of sulphuric acid on fluorite, and is usually
collected as a solution in water. It attacks all
silicates, as glass or porcelain, is the agent employed in
etching glass, and is preserved only in vessels of
platinum, lead, caoutchouc, or gutta-percha.