Ceriu

Ceriu
Lantan ← Ceriu → Praseodim -     58 Ce                                                                                                                                                                                                                                           Ce Th Tabelul complet • Tabelul extins
Informații generale
Nume, Simbol, Număr	Ceriu, Ce, 58
Serie chimică	lantanide
Grupă, Perioadă, Bloc	La, 6, l
Densitate	6689 kg/m³
Culoare	Argintiu
Număr CAS	7440-45-1[1][2]
Număr EINECS
Proprietăți atomice
Masă atomică	140,116 u
Rază atomică	185 pm
Rază de covalență	pm
Rază van der Waals	pm
Configurație electronică	[Xe]4f26s2
Electroni pe nivelul de energie	2, 8, 18, 19, 9, 2
Număr de oxidare	3, 4
Oxid
Structură cristalină	cubică
Proprietăți fizice
Fază ordinară	solidă
Punct de topire	798°C ; 1081 K
Punct de fierbere	3426°C ; 3699 K
Energie de fuziune	kJ/mol
Energie de evaporare	414 kJ/mol kJ/mol
Temperatură critică	K
Presiune critică	Pa
Volum molar	m³/kmol
Presiune de vapori
Viteza sunetului	2100 m/s la 293,15 K m/s la 20 °C
Forță magnetică
Informații diverse
Electronegativitate (Pauling)	-2,483 V (Ce3+ + 3e- → Ce) Scala Pauling1,12
Capacitate termică masică	J/(kg·K)
Conductivitate electrică	S/m
Conductivitate termică	=11,4 W/(m · K) W/(m·K)
Prima energie de ionizare	534,4 kJ/mol kJ/mol
A 2-a energie de ionizare	1050 kJ/mol kJ/mol
A 3-a energie de ionizare	1949 kJ/mol kJ/mol
A 4-a energie de ionizare	3547 kJ/mol kJ/mol
A 5-a energie de ionizare	{{{potențial_de_ionizare_5}}} kJ/mol
A 6-a energie de ionizare	{{{potențial_de_ionizare_6}}} kJ/mol
A 7-a energie de ionizare	{{{potențial_de_ionizare_7}}} kJ/mol
A 8-a energie de ionizare	{{{potențial_de_ionizare_8}}} kJ/mol
A 9-a energie de ionizare	{{{potențial_de_ionizare_9}}} kJ/mol
A 10-a energie de ionizare	{{{potențial_de_ionizare_10}}} kJ/mol
Precauții
NFPA 704
Unitățile SI și condiții de temperatură și presiune normale dacă nu s-a specificat altfel.
Modifică text

Ceriul este un element chimic din tabelul periodic care are simbolul Ce și numărul atomic 58.

Computed Tomography Solution for Automotive Components

A narrow x-ray beam is quickly spun around a patient’s body during a procedure known as “computed tomography,” or CT. This produces signals that are then analyzed by the machine’s computer to create cross-sectional images, or “slices,” of the patient’s body. These sections, which are known as tomographic pictures, can provide a clinician with more specific information than traditional x-rays. A three-dimensional (3D) image of the patient can be created once a number of successive slices have been collected by the machine’s computer. This makes it easier to identify the patient’s basic anatomy as well as any potential tumors or anomalies.

How does CT work? A CT scanner employs a motorized x-ray source that spins around the circular opening of a donut-shaped frame called a gantry, in contrast to a traditional x-ray, which uses a stationary x-ray tube. In a CT scan, the patient is lying on a bed that gently rotates across the gantry as a narrow beam of x-rays is shot into the body by the x-ray tube. Special digital x-ray detectors, which are placed immediately across from the x-ray source, are used in CT scanners in place of film. The detectors catch the x-rays as they leave the patient and send them to a computer.

Each time the x-ray source completes one full rotation, the CT computer uses sophisticated mathematical techniques to construct a two-dimensional image slice of the patient. The thickness of the tissue represented in each image slice can vary depending on the CT machine used but usually ranges from 1-10 millimeters. When a full slice is completed, the image is stored and the motorized bed is moved forward incrementally into the gantry. The x-ray scanning process is then repeated to produce another image slice. This process continues until the desired number of slices is collected.

The computer can either display the image slices separately or stack them to create a 3D image of the patient that displays the skeleton, organs, tissues and any anomalies the doctor is hoping to spot. This approach has various benefits, including the ability to rotate the 3D image in space or to see slices one after the other, which makes it simpler to pinpoint the precise location of a potential problem.