Calcium hexaboride

Calcium hexaboride

Names
IUPAC name Calcium hexaboride
Other names Calcium boride
Identifiers
CAS Number	12007-99-7 Y
3D model (JSmol)	Interactive image
ChemSpider	24765176 Y
ECHA InfoCard	100.031.374
EC Number	234-525-3
PubChem CID	16212529
InChI InChI=1S/B6.Ca/c1-2-3(1)5(1)4(1,2)6(2,3)5;/q-2;+2 Y Key: PXRBHCKHCRNGSE-UHFFFAOYSA-N Y InChI=1/B6.Ca/c1-2-3(1)5(1)4(1,2)6(2,3)5;/q-2;+2
SMILES [B-]123B45B16[B-]47B52B376.[Ca+2]
Properties
Chemical formula	CaB6
Molar mass	104.94 g/mol
Appearance	black powder
Density	2.45 g/cm3
Melting point	2,235 °C (4,055 °F; 2,508 K)
Solubility in water	insoluble
Structure
Crystal structure	Cubic
Space group	Pm3m ; Oh
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

Calcium hexaboride (sometimes calcium boride) is a compound of calcium and boron with the chemical formula CaB₆. It is an important material due to its high electrical conductivity, hardness, chemical stability, and melting point. It is a black, lustrous, chemically inert powder with a low density. It has the cubic structure typical for metal hexaborides, with octahedral units of 6 boron atoms combined with calcium atoms. CaB₆ and lanthanum-doped CaB₆ both show weak ferromagnetic properties, which is a remarkable fact because calcium and boron are neither magnetic, nor have inner 3d or 4f electronic shells, which are usually required for ferromagnetism.

CaB₆ has been investigated in the past due to a variety of peculiar physical properties, such as superconductivity, valence fluctuation and Kondo effects. However, the most remarkable property of CaB₆ is its ferromagnetism. It occurs at unexpectedly high temperature (600 K) and with low magnetic moment (below 0.07 ${\displaystyle \mu _{\mathrm {B} }}$ per atom). The origin of this high temperature ferromagnetism is the ferromagnetic phase of a dilute electron gas, linkage to the presumed excitonic state in calcium boride, or external impurities on the surface of the sample. The impurities might include iron and nickel, probably coming from impurities in the boron used to prepare the sample.