Krom

24
Cr
Golongan
6
Periode
4
Blok
d
Proton
Elektron
Neutron
24
24
28
Sifat Umum
Nomor atom
24
Massa atom
51,9961
Nomor massa
52
Kategori
Logam transisi
Warna
Perak
Radioaktif
Tidak
From the Greek word chroma, color
Struktur kristal
Kubik Berpusat-badan
Sejarah
In 1797, Louis Nicolas Vauquelin received samples of crocoite ore.

In 1798, Vauquelin discovered that he could isolate metallic chromium by heating the oxide in a charcoal oven, making him the discoverer of the element.

Vauquelin was also able to detect traces of chromium in precious gemstones, such as ruby or emerald.
Elektron per kulit
2, 8, 13, 1
Konfigurasi elektron
[Ar] 3d5 4s1
Cr
Chromium oxide was used by the Chinese in the Qin dynasty over 2,000 years ago
Sifat Fisika
Fase
Solid
Kepadatan
7,15 g/cm3
Titik lebur
2180,15 K | 1907 °C | 3464,6 °F
Titik didih
2944,15 K | 2671 °C | 4839,8 °F
Kalor peleburan
20,5 kJ/mol
Kalor penguapan
339 kJ/mol
Kapasitas kalor molar
0,449 J/g·K
Kelimpahan di kerak bumi
0,014%
Kelimpahan di alam semesta
0,0015%
High
Kredit Gambar: Wikimedia Commons (Alchemist-hp)
High purity chromium crystals, produced by chemical transport reaction through decomposition of chromium iodides, as well as a high purity chromium cube for comparison
Nomor CAS
7440-47-3
PubChem CID Number
23976
Sifat Atom
Jari-jari atom
128 pm
Jari-jari kovalen
139 pm
Elektronegativitas
1,66 (Skala Pauling)
Potensi Ionisasi
6,7665 eV
Volume atom
7,23 cm3/mol
Kondusivitas termal
0,937 W/cm·K
Bilangan oksidasi
-2, -1, 1, 2, 3, 4, 5, 6
Aplikasi
Chromium is used to harden steel, manufacture stainless steel, and form many useful alloys.

It is mostly used in plating to produce a hard, beautiful surface and to prevent corrosion.

The metal is also widely used as a catalyst.

Chromium compounds are valued as pigments for their vivid green, yellow, red and orange colors.
In larger amounts, chromium can be toxic and carcinogenic
Isotop
Isotop stabil
50Cr, 52Cr, 53Cr, 54Cr
Isotop tidak stabil
42Cr, 43Cr, 44Cr, 45Cr, 46Cr, 47Cr, 48Cr, 49Cr, 51Cr, 55Cr, 56Cr, 57Cr, 58Cr, 59Cr, 60Cr, 61Cr, 62Cr, 63Cr, 64Cr, 65Cr, 66Cr, 67Cr