GRUPO 15

GRUPO 15

Elementos: N, P, As, Sb, Bi

Posição na tabela periódica

configuração eletrônica: [...] n s2 n p3 n = 2 a 6

estados de oxidação: As- ±3; Sb- ±3; Bi- 3, 5;

P- ±3, 5; N- ±1, 2, 3; +4, +5

raio

covalente

(A)

energia de

ionização*

(kJ mol-1

)

eletronegati

vidade

abundância

na terra

(ppm)

N 0,74 8838 3,0 46,3

P 1,10 5819 2,1 1180

As 1,21 5629 2,0 5

Sb 1,41 4864 1,9 1

Bi 1,52 4780 1,9 0,2

*- soma das 3 energias

Ocorrência e obtenção

N- atmosfera terrestre (78%), nitratos (NaNO3). Obtido por

destilação fracionada do ar.

em laboratório:

NH4Cl + NaNO2 NH4NO2 N2 + 2 H2O

4NH3 + 3Ca(OCl)2 3CaCl2 + 6H2O + 2N2

2NaN3 2Na + 3N2

N:

used in ammonia, NH3, production (Haber process). This is the greatest use of nitrogen. Ammonia is used for fertilizer production and to produce nitric acid (Ostwald process)

used by the electronics industry, which uses the gas as a blanketing medium during production of such components as transistors, diodes, etc.

used as a refrigerant (PE= -195,8 0C) both for the immersion

freezing of food products and for transportation of foods

liquid nitrogen is used by the oil industry to build up pressure in wells to force crude oil upward

used as an inert atmosphere in explosive liquid storage tanks, both in ground-based tanks and in ships

Nitrogen is a key component of biological molecules such as proteins (which are made from amino acids), and nucleic acids.

~26g/kg no corpo humano.

fertilizantes: (NH4)2SO4, uréia- (NH2)2CO

amônia: processo Haber

esta reação é exotérmica! Por que usar então 450 0C?

!

!

Nature 427, 527 - 530 (05 February 2004); doi:10.1038/nature02274

Hydrogenation and cleavage of dinitrogen to

ammonia with a zirconium complexJAIME A. POOL, EMIL LOBKOVSKY & PAUL J. CHIRIK

P- rochas fosfatadas. Obtido por redução com carbono e

silício, em forno elétrico a 1300 0C

• 2Ca3(PO4)2 + 6SiO2 6CaSiO3 + P4O10

P4O10 + 10C P + 10CO

•2Ca3(PO4)2(s) + 10C(s) + 6SiO2(s) P4(s) + 10CO

+6CaSio3(s)

used in the manufacture of safety matches, pyrotechnics, incendiary shells, smoke bombs

fertilisers

Na3PO4 is important as a cleaning agent, as a water softener, and for preventing boiler scale and corrosion of pipes and boiler tubes

pesticides

Phosphorus is a key component of biological molecules such as DNA and RNA. Phosphorus is a component of bones, and teeth, and many other compounds required for life.

Chronic poisoning of people working unprotected with white phosphorus leads to necrosis of the jaw

~11g/kg no corpo humano.

superfosfato e superfosfato triplo:

•Ca2H2(PO4)2 + CaSO4

•Ca3H3(PO4)3

•produção de ácido fosfórico (maior consumo)

As: realgar (As4S4), orpiment (As2S3), arsenolita (As2O3), arsenopirita (FeAsS) e loelingita (FeAs2)

FeAsS (700°C) FeS + As(g) As(s)

doping agent in solid-state devices such as transistors

the arsenide is used as a laser material to convert electricity directly into coherent light

despite its poisonous reputation, may be a necessary ultratrace element for humans. It is a necessary ultratrace element for red algae, chickens, rats, goats, and pigs. A deficiency results in inhibited growth.

•combate à malária: arsenatos orgânicos

C&EN

Bi: bismita (Bi2O3), bismutinita (Bi2S3), e

bismutita [(BiO)2CO3 ].

Subproduto das plantas de produção de cobre, chumbo, estanho, prata, ouro e zinco.

A etapa final envolve redução do óxido por carvão mineral.

used in producing malleable irons

as a catalyst for making acrylic fibres

as a thermocouple material

cosmetics

Bismuth has no biological role.

However it has been used for some time as a medicine (tripotassium dicitratobismuthate) for treatment of stomach upsets.

In combination with antibiotics it is now used for treatment of some stomach ulcers.

Sb: Stibinita (Sb2S3) e ulmanita (NiSbS).

Sb2S3 + 3Fe 2Sb + 3FeS

2Sb2O3 +3C 4Sb + 3CO2

used in semiconductor technology for making infrared detectors, diodes, and Hall-effect devices

used in alloys with percentages ranging from 1 to 20 - greatly increases the hardness and mechanical strength of lead

batteries

oxides, sulphides, sodium antimonate, and antimony trichloride are used in manufacturing flame-proofing compounds

tartar emetic (hydrated potassium antimonyltartate) is used in medicine

Antimony has no biological role. In small doses it is said to stimulate the metabolism.

Combate à Leishmaniose: antimoniatos

propriedades

•caráter metálico- varia de não-metais (N, P) a metais (Bi)

•estruturas:

•N2- gás

•fósforo branco (tetraedro C4), fósforo vermelho

(polimerizada), fósforo preto

•As e Sb- forma tetraédrica e metálica

•Bi- forma metálica

•o íon M+5 não existe (Eioniz muito alta!)

•Sb e Bi podem existir como M+3, porém só formam

compostos iônicos com o fluor (SbF3, BiF3)

•o nitrogênio é capaz de formar ligações múltiplas p-p fortes (*). Seu

número de coordenação máximo é quatro.

•os outros elementos podem ter número de coordenação cinco ou seis.

compostos

óxidos•óxidos de nitrogênio vão dos neutros aos ácidos

N2O; NO; NO2 N2O4; N2O3; N2O5; NO3; N2O6

•NO- diamagnético no estado sólido, com formação de

dímeros. No estado gasoso é paramagnético. Reage com

halogênios, formando haletos de nitrosila (ex. NOCl),

atuando ainda como ligante na presença de metais de

transição.

N2

October 12, 1998

The Nobel Assembly at Karolinska Institutet has today decided

to award the Nobel Prize in Physiology or Medicine for 1998

jointly to

Robert F. Furchgott, Louis J. Ignarro and Ferid Murad

for their discoveries concerning "nitric oxide as a signalling

molecule in the cardiovascular system".

Summary

Nitric oxide (NO) is a gas that transmits signals in the

organism. Signal transmission by a gas that is produced by one

cell, penetrates through membranes and regulates the function

of another cell represents an entirely new principle for

signalling in biological systems. The discoverers of NO as a

signal molecule are awarded this year's Nobel Prize.

http://www.nobel.se/medicine/laureates/1998/

Nitric oxide protects the heart, stimulates the brain, kills bacteria, etc. It was a sensation that this simple, common air pollutant, which is formed when nitrogen burns, for instance in automobile exhaust fumes, could exert important functions in the organism. It was particularly surprising since NO is totally different from any other known signal molecule and so unstable that it is converted to nitrate and nitrite within 10 seconds. NO was known to be produced in bacteria but this simple molecule was not expected to be important in higher animals such as mammals. NO is a signal molecule of key importance for the cardiovascular system and it was also found to exert a series of other functions. We know today that NO acts as a signal molecule in the nervous system, as a weapon against infections, as a regulator of blood pressure and as a gatekeeper of blood flow to different organs. NO is present in most living creatures and made by many different types of cells. - When NO is produced by the innermost cell layer of the arteries, the endothelium, it rapidly spreads through the cell membranes to the underlying muscle cells. Their contraction is turned off by NO, resulting in a dilatation of the arteries. In this way, NO controls the blood pressure and its distribution. It also prevents the formation of thrombi. - When NO is formed in nerve cells, it spreads rapidly in all directions, activating all cells in the vicinity. This can modulate many functions, from behaviour to gastrointestinal motility. - When NO is produced in white blood cells (such as macrophages), huge quantities are achieved and become toxic to invading bacteria and parasites.

Diagnostic analyses: Inflammatory diseases can be revealed by analysing the production of NO from e.g. lungs and intestines. This is used for diagnosing asthma, colitis, and other diseases. NO is important for the olfactory sense and our capacity to recognise different scents. It may even be important for our memory. Nitroglycerin Alfred Nobel invented dynamite, a product in which the explosion-prone nitroglycerin is curbed by being absorbed in kieselguhr, a porous soil rich in shells of diatoms. When Nobel was taken ill with heart disease, his doctor prescribed nitroglycerin. Nobel refused to take it, knowing that it caused headache and ruling out that it could eliminate chest pain. In a letter, Nobel wrote: It is ironical that I am now ordered by my physician to eat nitroglycerin. It has been known since last century that the explosive, nitroglycerin, has beneficial effects against chest pain. However, it would take 100 years until it was clarified that nitroglycerin acts by releasing NO gas.

NO2- gás castanho-avermelhado

em laboratório:

2Pb(NO3)2 2PbO + 4NO2 + O2

Cu + 4HNO3 Cu(NO3)2 + 2NO2 + 2H2O

N2O5- anidrido do ácido nítrico

Processo Ostwald para produção de ácido nítrico

N2 + 3H2 2NH3200 atm

Fe, 500 0C

2NH3 + O2 NO NO2* HNO3

5-10 atm

Pt/Rh ~900 0C

(processo Haber)

* 3NO2 + H2O 2HNO3 + NO

reação muito exotérmica*

http://www.carlton.srsd119.ca/chemical/mtom/contents/chapter3/fritzhaber_2.htm

•óxidos de fósforo- formados pela combustão direta em presença de

ar ou oxigênio

oxiácidos:

ácidos fosfóricos: P(V); ácidos oxidantes

H3PO4- ácido ortofosfórico

Ca3(PO4)2 + 3H2SO4 2H3PO4 + 3CaSO4

P4O10 + 6H2O 4H3PO4

P + HNO3 H3PO4

H3PO4 H4P2O7 (HPO3)n

aquec. aquec. forte

ác. pirofosfórico ác. metafosfórico

P4O10

P4O6

•ácidos fosforosos: P(III)

H3PO3- ácido ortofosforoso

H3PO3 H4P2O5 (HPO2)n

ác. pirofosforoso ác. metafosforoso

óxidos de As, Sb e Bi:

As4O6, As4O10, Sb4O6, Sb4O10, Bi2O3

haletos

•trialetos (MX3)- todos os trialetos são conhecidos, sendo o de

nitrogênio o menos estável. Têm estruturas tetraédricas, com um dos

vértices ocupados por um par de elétrons livres. São

predominantemente covalentes.

•pentaletos (MX5)- o único que não pode formá-los é o nitrogênio

(por que?)

PF5, PCl5, PBr5, AsF5, SbF5

hidretos

•todos os elementos formam hidretos voláteis, com fórmula geral

AH3.

•a formação de ligações com o par de elétrons livres diminui do N

para o Bi.

•a estabilidade dos hidretos decresce de cima para baixo, com a

diminuição da energia de ligação A-H.

pKa=9,25

sp3

FERTILIZANTES

NITROGENADOS

FIXAÇÃO INDUSTRIAL

ALIMENTAÇÃO

E EXCREÇÃO ANIMAL

NITRATOS

( NO3- )

SAIS DE AMÔNIO

( NH4+ )

BACTÉRIAS NO SOLO

BACTÉRIAS NO SOLO

FIXAÇÃO BIOLÓGICA

POR LEGUMINOSAS

E CIANOBACTÉRIAS

CULTIVARES

NÃO LEGUMINOSAS

PLANTAS NÃO FIXADORAS

DE NITROGÊNIO

DESNITRIFICAÇÃO

ADUBO

ALIMENTAÇÃO

E EXCREÇÃO ANIMAL

NITROGÊNIO ( N2 )

GASOSO NO AR

FIXAÇÃO

ATMOSFÉRICA

FERTILIZANTES

NITROGENADOS

FIXAÇÃO INDUSTRIAL

ALIMENTAÇÃO

E EXCREÇÃO ANIMAL

NITRATOS

( NO3- )

SAIS DE AMÔNIO

( NH4+ )

BACTÉRIAS NO SOLO

BACTÉRIAS NO SOLO

FIXAÇÃO BIOLÓGICA

POR LEGUMINOSAS

E CIANOBACTÉRIAS

CULTIVARES

NÃO LEGUMINOSAS

PLANTAS NÃO FIXADORAS

DE NITROGÊNIO

DESNITRIFICAÇÃO

ADUBO

ALIMENTAÇÃO

E EXCREÇÃO ANIMAL

NITROGÊNIO ( N2 )

GASOSO NO AR

FIXAÇÃO

ATMOSFÉRICA

Ciclo do nitrogenio

Eventos recentes

Los Angeles - primeiras observações do

“Smog” fotoquímico são feitas

ainda nos anos 40

Sun

NOx (nitrogen oxides)Organic compounds

(hydrocarbons)

Concentrated

photochemical smog

(brown air)

Solar radiation

in urban area

With the presence of an inversion

layer, trapping pollutants

+

O2H H

C C

R1 R2

+ OH. C C

R1

H H

R2

.OH

C C

R1

H H

R2

OHOO.

OHO C C

R1

H H

R2

.

NO2.

+

C

H

R2

O

.OOH

C

R1

H

O + OHC

H

R2

.O2 +

NO

v

+

NO2 .

+

+ O

O O2 O3

HO. +

NO2 . NO .

HNO3

HO. NO . HONO

hv

hv

NO2 . + O3 NO3 + O2

HNO3, R

NO2., H2O