 |
|
| A B C D E F G H I J K L M N O P Q R S T U V W X Y Z |
| • HOME • ABOUT • CATEGORIES • COPYRIGHT • NEWSLETTER   
|
hydride
A binary compound of hydrogen with another, more electropositive element or group (one that loses electrons and forms positive ions). Hydride ions and hydride ionic compounds react instantly and sometimes violently with water.
There are several different types of hydrides.
- Salt-like. These are the hydrides of the most electropositive elements (e.g. sodium) and contain ions. They are crystalline solids and react violently with water to give hydrogen.
- Covalent. These are formed by most of the non-metals and transition metals, in groups IB–VIIA of the periodic table. They are mainly volatile, reactive compounds, though those of groups IB and IIB, and aluminum, are nonvolatile polymers. Covalent hydrides include such diverse compounds as methane and iron carbonyl hydride, H2Fe(CO)4. In many compounds the hydrogen atoms act as a bridges. Where there are more than one hydride sites there is often hydrogen exchange between the sites.
- Complexes. These derivatives contain complex anions which may be considered as derived from co-ordination of an H- ion to a metal or non-metal. Examples are the BH4- and ReH92- ions.
- Transition metal hydrides. These are formed by hydrogen uptake by transition elements (groups IIIB–VIII). The phases are often non-stoicheiometric and electrically conducting. They resemble alloys and some have interstitial structures.
Related category
• INORGANIC CHEMISTRYAlso on this site:
Encyclopedia of Alternative Energy & Sustainable Living
Encyclopedia of History