Formula: B
Element, metalloid, does not occur in the native state on Earth, although it has been identified from the moon
Specific gravity: 2.34
Colour: Black
Solubility: Insoluble in nitric and hydrochloric acids
Melting point: 2075oC
Boiling point: 3727oC
Abundance in the Earth’s crust: 10 parts per million by mass, 1 part per million by moles
Abundance in the Solar System: 2 parts per billion by mass, 0.2 parts per billion by moles
Boron compounds are usually found in sediments and sedimentary rock formations. The chief sources of boron are
kernite, borax and
colemanite. In compounds boron almost always occurs as trivalent
B3+
(ChC)
Boron-bearing minerals include:
Oxides
touretite
Borides - borides are usually covalent rather than ionic
jingsuiite
Chlorides - the chloride anion is Cl-
vladkrivovichevite
Fluorides - the fluoride anion is F-
avogadrite
barberiite
ferruccite
Monoborates - with a single boron anion (BO3)3- or B(O,OH)4
bandylite
berborite
bonaccordite
chiyokoite
fluoborite
folvikite
fredrikssonite
frolovite
gaudefroyite
hambergite
hulsite
hydroxylborite
jacquesdietrichite
jeremejevite
jimboite
kotoite
ludwigite
lüneburgite
nordenskiöldine
pseudosinhalite
rhabdoborite-(Mo)
rhabdoborite-(V)
rhabdoborite-(W)
sakhaite
sassolite
savelievaite
sibirskite
sinhalite
takedaite
tusionite
vonsenite
warwickite
Diborates - with double boron triangles and/or tetrahedra
calciborite
parasibirskite
pentahydroborite
suanite
sussexite
szaibélyite
wiserite
Triborates
colemanite
howlite
hydroboracite
inderborite
inderite
inyoite
kurnakovite
meyerhofferite
nifontovite
olshanskyite
Tetraborates
borax
borcarite
kernite
tincalconite
uralborite
Pentaborates
calcioveatchite
gowerite
hilgardite
kurgantaite
priceite
probertite
ulexite
volkovskite
Hexaborates
ginorite
strontioborite
strontioginorite
tunellite
Heptaborates
boracite
congolite
ericaite
trembathite
Nonaborates
penobsquisite
studenitsite
Megaborates
pringleite
Sulphates - the sulphate anion is (SO4)2-
tatarinovite
Phosphates - the phosphate anion is (P5+O4)3-
seamanite
Nesosilicates
arrheniusite-(Ce)
cappelenite-(Y)
grandidierite
hellandite-(Y)
melanocerite-(Ce)
ominelite
stillwellite-(Ce)
Sorosilicate - (Si4+2O7)6- groups
boralsilite
kornerupine
tinzenite
werdingite
Cyclosilicates - (Si4+nO3n)2n- groups
alumino-oxy-rossmanite
chromium-dravite
darrellhenryite
dravite
fluor-buergerite
fluor-dravite
fluor-liddicoatite
fluor-schorl
fluor-uvite
itsiite
magnesio-foitite
maruyamaite
oxy-chromium-dravite
oxy-dravite
oxy-schorl
princivalleite
schorl
tienshanite
titantaramellite
Inosilicates - single chain - (Si4+nO3n)2n- groups
hellandite-(Ce)
serendibite
Phyllosilicates - (Si4+2O5)2- groups
leucosphenite
oyelite
searlesite
Tectosilicate - [Al3+xSi4+OyO(2x+2y)]x−
lisitsynite