Holmium

Symbol	Ho
Atomnummer	67
Gruppe	-
Periode	6
Blok	f
Klassifikation	Lanthanider

Udseende	Silvery white
Farve	Sølv

Antal protoner	67 p+
Antal neutroner	98 n0
Antal elektroner	67 e-

Fra Wikipedia, den gratis encyklopædiHolmium (efter Stockholms latinske navn Holmia) er det 67. grundstof i det periodiske system, og har det kemiske symbol Ho: Under normale temperatur- og trykforhold optræder dette lanthanid som et blødt, sølvskinnende metal. Holmium er nogenlunde modstandsdygtigt overfor iltning ("rust") i tør atmosfærisk luft, men i fugtig luft eller ved højere temperaturer angribes det hurtigt, og danner et gulligt oxid. Ved temperaturer over 150 °C antændes metallet, og danner holmiumsesquioxid (Ho₂O₃). Holmium reagerer med vand under dannelse af gasformig brint samt holmiumhydroxid, og kan opløses i uorganiske syrer hvorved der også dannes brint. I vandige opløsninger danner holmium en kation, Ho+++, som farver opløsningen gul. Holmium har en række usædvanlige magnetiske egenskaber, bl.a. det højeste magnetiske moment blandt alle naturligt forekommende grundstoffer. Sammen med yttrium danner det stærk magnetiske stoffer.

Fase ved STP	Fast
Massefylde	8.79 g/cm3
Atommasse	164.93 u

Smeltepunkt	1734 K 1460.85 °C 2661.53 °F
Kogepunkt	2873 K 2599.85 °C 4711.73 °F
Fordampningsvarme	251.04 kJ/mol

Elektronegativitet (Pauling Scale)	1.23
Elektronaffinitet	32.61 kJ/mol
Oxidationstrin	0, +1, +2, +3 (a basic oxide)
Ioniseringsenergier	581 kJ/mol 1140 kJ/mol 2204 kJ/mol 4100 kJ/mol

Elektronkonfiguration Kortfattet konfiguration	[Xe] 4f11 6s2
Elektronkonfiguration Fuld konfiguration	1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f11 5s2 5p6 6s2
Elektronkonfigurationsdiagram	1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f11 5s2 5p6 6s2
Elektroner pr. Skal	2, 8, 18, 29, 8, 2
Outer shell electrons	2
Valency-elektroner	3
Bohrs atommodel	Figur: Skaldiagram af Holmium (Ho) atom.
Orbital diagram 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 6s

Opdaget	Jacques-Louis Soret, Marc Delafontaine (1878)
Første isolation	Per Teodor Cleve (1879)
Navngivet af	Per Teodor Cleve (1879)
Opdagelse af holmium Holmium was discovered through isolation by Swedish chemist Per Theodor Cleve and independently by Jacques-Louis Soret and Marc Delafontaine, who observed it spectroscopically in 1878. Its oxide was first isolated from rare-earth ores by Cleve in 1878. The element's name comes from Holmia, the Latin name for the city of Stockholm. As well, Per Teodor Cleve independently discovered the element while he was working on erbia earth (erbium oxide), and was the first to isolate it. Using the method developed by Carl Gustaf Mosander, Cleve first removed all of the known contaminants from erbia. The result of that effort was two new materials, one brown and one green. He named the brown substance holmia (after the Latin name for Cleve's home town, Stockholm) and the green one thulia. Holmia was later found to be the holmium oxide, and thulia was thulium oxide. Like many other lanthanides, holmium is found in the minerals monazite and gadolinite and is usually commercially extracted from monazite using ion-exchange techniques.

Original word	Holmia
Language of origin	Latin
Name source	Sted
Meaning	“Holmia (Stockholm)”
Land	Sweden
Naming The name is derived from the Latin word for the city of Stockholm, Holmia.

CAS Number	7440-60-0
ChemSpider ID	22424
EC number	231-169-0
PubChem CID Number	23988